PL193700B1 - Biodegradable shape memory polymers, and their use - Google Patents

Abstract

Degradable shape memory polymer composition characterized in that it comprises at least one hard segment whose transition temperature Ttrans is in the range from - 40 to 270 ° C, and at least one segment associated with at least one hard segment soft, the transformation temperature of which Ttrans is at least 10 ° C lower than the transformation temperature The Ttrans of the hard segment (s), and further at least one of the hard or soft segments has a degradable region, or at least one pair of hard and soft segments has a bond degradable. 19. Use of the degradable shape memory polymer composition according to claim 1 for the production of technical, pharmaceutical, biomedical and cosmetic articles and equipment and care products, such as, for example, capsules, surgical threads, orthodontic materials, rails, rods, screws, nails and plates used in bone surgery, tissue engineering scaffolds, films, drainage tubes, catheters, prostheses, transplants and implants, contact lenses, pumps and meshes, dosing devices light gauges and thermal sensors, diapers, sanitary napkins and packaging, contrast agents, used, among others, in tomographic, resonance and x-ray examinations.

Description

Description of the invention

Object of the invention

The present invention relates to a shape memory degradable polymer composition. Furthermore, the invention relates to the use of a degradable polymer composition with a shape memory, in particular for the production of technical, pharmaceutical, biomedical, cosmetic and beauty articles and devices.

State of the art

Shape memory is the ability of a material to remember its original shape after mechanical deformation, which is a unidirectional effect, or after thermal deformation due to cooling and heating, which is a two-way effect. This phenomenon is based on the transformation of the structural phase.

The first known materials with the above-mentioned properties were shape memory metal alloys (SMA), including TiNi (Nitinol), CuZnAl and FeNiAl alloys. The transformation of the structural phase of these materials is referred to as the martensitic transformation. These materials are used in a variety of applications including vascular drainage tubes, medical guide tubes, orthodontic wires, vibration dampers, tubular connectors, electrical connectors, thermostats, actuating members, spectacle frames, and bra wires. However, it should be noted that the use of the above-mentioned alloys is limited, especially due to their high price.

However, shape memory polymers (SMPs) are increasingly used to replace or complement the use of SMA, in part because these polymers are lighter in weight, have much higher shape recoverability, are easy to handle, and more economical to use. In the literature, SMPs are generally characterized as phase segregated, linear copolymers having a hard segment and a soft segment. The hard segment is typically crystalline with a defined melting point and the soft segment is typically amorphous with a defined glass transition temperature. However, in some embodiments, the hard segment is amorphous and has a glass transition temperature rather than a melting point. In other embodiments, the soft segment is crystalline and has a melting point rather than a glass transition temperature. The melting point or glass transition temperature of the soft segment is significantly lower than the melting point or glass transition temperature of the hard segment.

When the SMP is heated above the melting point or glass transition temperature of the hard segment, the material can be shaped. This (original) shape can be remembered by cooling the SMP below the melting point or glass transition temperature of the hard segment. When the shaped SMP is cooled to below the melting point or glass transition temperature of the soft segment during which the shape is deformed, the (temporary) shape is established. The original shape is recovered by heating the material above the melting point or glass transition temperature of the soft segment but below the melting point or glass transition temperature of the hard segment. In another method to establish a temporary shape, the material is deformed at a temperature lower than the melting point or glass transition temperature of the soft segment, resulting in stress and deformation being absorbed by the soft segment. When the material is heated above the melting point or glass transition temperature of the soft segment but below the melting point (or glass transition temperature) of the hard segment, stresses and strains are relieved and the material returns to its original shape. The recovery of the original shape, which is caused by the increase in temperature, is called the thermal shape memory effect. The properties that describe the shape memory capacity of a material are the shape recovery of the original shape and the shape setting of the temporary shape.

Several of the physical properties of SMP, other than shape memory, are significantly altered in response to external changes in temperature and stress, particularly with the melting point or glass transition temperature of the soft segment. These properties include elastic modulus, hardness, compliance, vapor permeability, damping, refractive index, and dielectric constant. The modulus of elasticity (ratio of body stress to corresponding strain) of the SMP can vary by a factor of up to 200 when heated above the melting point or glass transition temperature of the soft segment. Also, the hardness of the material changes dramatically when the soft segment is at or above its melting point or glass transition temperature. When the material is heated to a temperature above the melting point or glass transition temperature of the soft segment, the damping capacity can be up to five times

PL 193 700 B1 higher than that of a conventional rubber product. The material can easily regain its original shaped shape after numerous thermal cycles and can be heated above the melting point of the hard segment and be altered in shape and have a new original shape established upon cooling.

Conventional shape memory polymers are generally segmented polyurethanes and have hard segments containing aromatic specific portions. For example, US Patent No. 5,145,935 to Hayashi discloses a shape memory article formed of a polyurethane elastomer polymerized from a difunctional diisocyanate, a difunctional polyol, and a difunctional chain extender.

Examples of polymers used to prepare the hard and soft segments of the known SMPs include various polyethers, polyacrylates, polyamides, polysiloxanes, polyurethanes, polyether amides, polyurethane / ureas, polyether esters and urethane / butadiene copolymers. See, for example, US Patent No. 5,506,300 to Ward et al; U.S. Patent No. 5,145,935 to Hayashi; U.S. Patent No. 5,665,822 to Bitler et al; and Gorden, "Applications of Shape Memory Polyurethanes, Proceedings of the First Internationa Conference on Shape Memory and Superelastic Technologies, SMST International Committee, pp. 115-19 (1994).

While these polymers have been proposed for a number of applications, their medical uses have been limited to devices that are not implanted or left in the body. It is desirable to have shape memory polymers that are biodegradable. Many applications of biodegradable shape memory polymers are obvious, for example, in making diapers and sanitary napkins or medical surgical liners, or in food packaging or other materials wherever disposal measures are indicated. It is not obvious from the characteristics of known commercially available polyurethane materials that biodegradable materials can be incorporated into the shape memory polymer and retain the structural and other physico-chemical properties that are characteristic of shape memory polymers and their applications. . Moreover, the components of the known shape memory polyurethane polymers contain aromatic groups which would be expected to be biocompatible.

In view of the above, it was an object of the invention to develop and implement biodegradable shape memory polymers.

Yet another goal was to obtain a qualitatively new type of shape memory polymers with different, more useful physico-chemical and structural properties as compared to the prior art.

The essence of the invention

The essence of the first invention consists in the fact that the polymer composition comprises at least one hard segment, the transformation temperature of which Ttrans is in the range of -40 to 270 ° C, and at least one soft segment associated with at least one hard segment, the transformation temperature Ttrans is at least 10 ° C lower than the transformation temperature Ttrans of the hard segment (s), in addition, at least one of the hard or soft segments has a degradable region, or at least one pair of hard and soft segments has a degradable bond degradation.

It is preferred that the composition comprises shape memory polymers that are exposed to external stimuli, especially temperature or light.

It is also advantageous if the transformation temperature Ttrans of the hard segment is in the range from 30 to 150 ° C, preferably up to 100 ° C.

It is furthermore preferred that the transformation temperature Ttrans of the soft segment (s) is at least 20 ° C lower than the transformation temperature Ttrans of the hard segment (s).

It is also advantageous if at least one of the hard and soft segments is a thermoplastic polymer.

Moreover, it is advantageous if cyclic parts are present in the hard segment.

It is also preferred that the weight ratio of the hard and soft segments is in the range from about 5: 95 to 95: 5, preferably from 20: 80 to 80: 20.

Furthermore, it is preferred that the shape memory polymer belongs to the group consisting of graft, linear and dendritic polymers.

It is also significantly advantageous if the degradable region of the polymer belongs to the group consisting of polyhydric acids, ether polyesters, polyorthoesters, polyamino acids.

Words, synthetic polyamino acids, polyanhydrides, polycarbonates, polyhydroxyalkanoates, and polyphaprolactones).

It is preferred that the polymer contains a biodegradable bond which belongs to the group consisting of ester, carbonate, amide, anhydride and orthoester subgroups.

It is also advantageous if the composition comprises a completely biodegradable polymer.

It is significantly preferred that the composition comprises a degradable thermosetting polymer which in turn comprises a crystallizing soft segment having a cross-linked covalent structure having a melting point Tm ranging from 250 ° C to (-) 40 ° C, preferably from 200 ° C to 0 ° C. ° C, or a cross-linked covalent soft segment having a transition temperature Ttrans ranging from 250 ° C to (-) 60 ° C, preferably from 200 ° C to 0 ° C.

It is also advantageous if the composition comprises at least two segments:

a) the first segment, the transformation temperature of which Ttrans is in the range from -40 to 270 ° C,

b) a second segment which is associated with at least one first segment and which is an ionic interaction of sufficient strength that the second segment is capable of forming a physical cross-link other than at the melting or glass transition temperature, at least one of the segments having a melting point. the biodegradable region or at least one of the first segments is bound to at least one of the second segments through a biodegradable bond.

Furthermore, it is preferred that the ionic interaction is polyelectolytic segments, or polyelectolytic segments and ions, or polyanionic and polycationic segments, or supramolecular effects based on highly organized hydrogen bonds.

It is also advantageous if the polymer has an inverse temperature effect whereby the shape of the composition is recovered upon cooling below the shape recovery temperature.

It is furthermore preferred that the composition comprises polymer compositions comprising two-, three- or four-block copolymers and one homo- or copolymer.

It is significantly preferred that the composition comprises a polymer set belonging to the group consisting of physical polymer mixtures, polymer sets containing hard segments with different transformation temperatures Ttrans and soft segments with the same transformation temperature Ttrans, sets of multi-block copolymers in which at least one of the first copolymer segments it is miscible with at least one of the segments of the second copolymer, and sets of at least one multiblock copolymer and at least one homo- or copolymer.

It is also preferred that the composition includes a coating that modifies the degradation of the shape memory polymer.

The essence of the second invention is the use of the polymer composition according to the invention for the production of technical, pharmaceutical, biomedical, cosmetic and care articles and devices, such as capsules, surgical threads, orthodontic materials, splints, rods, screws, nails and plates used in bone surgery, scaffolding for tissue engineering, films, drainage tubes, catheters, prostheses, transplants and implants, contact lenses, pumps and meshes, light dosing devices, indicators and thermal sensors, diapers, sanitary napkins and packaging, contrast agents, used, inter alia, in tomography, resonance and X-rays.

The above biocompatible polymer compositions contain one or more hard segments and one or more soft segments, wherein at least one polymer contained therein or at least one segment bond is biodegradable.

In contrast, shape memory polymers contain at least one physical cross-link (physical interaction of the hard segment) or contain a covalent cross-link in place of the hard segment. These polymers can also be networks that interpenetrate - wholly or partially.

In addition to changes from solid to liquid (melting point or glass transition point), the hard and soft segments can undergo solid to solid changes, they can also be subject to ionic interactions involving polyelectrolytic segments or supramolecular phenomena based on highly organized hydrogen bonds.

Polymer products can be obtained from the shape memory polymer composition by, for example, injection molding, blowing, extrusion, and laser removal. To prepare a memory shaped article, the product may be formed at a temperature below the Ttrans

Of the hard segment and cooled to a temperature below the Ttrans of the soft segment. The original shape can be restored by heating the article above the Ttrans of the soft segment and below the Ttrans of the hard segment.

Thermosetting polymers can be prepared by preforming macromoners, for example by extrusion, and setting the original shape at a temperature above the Ttrans of the thermosetting polymer, for example by photo-curing the active groups on the macromonomer.

Examples

The invention will be presented on the basis of exemplary embodiments shown in the drawing, in which:

Fig. 1 is an illustration of a one-way shape memory effect;

Fig. 2 is an illustration of a two-way (thermal) shape memory effect;

Fig. 3 is an illustration of a combination of suitable classes of thermoplastic materials;

Fig. 4 is a reaction sequence diagram for the synthesis of a preferred crosslinking;

Fig. 5 is an illustration of a photo evoked shape memory effect.

Fig. 6 is an illustration of a thermal shape memory effect mechanism for a multi-block copolymer.

Fig. 7 is a graph showing stress versus elongation for a shape memory polymer of a multiblock copolymer.

Fig. 8 is a graph showing the melting point of diols, dimethacrylates and polyphaprolactone thermosetting materials as a function of the molar mass of M _n macromonomers.

Detailed Description of the Invention

Biodegradable shape memory polymer compositions, articles manufactured therefrom, and methods of preparing and using them are described.

Definitions

As used herein, the term "biodegradable" refers to materials that are biologically resorbed and / or degraded and / or degraded by mechanical degradation upon interaction with the physiological environment on parts that are metabolized or secreted for a period ranging from minutes to three. years, preferably less than one year, while the necessary structural integrity is maintained. As used herein with respect to polymers, the term "to degrade" refers to the cleavage of the polymer chain such that the molecular weight remains approximately constant at the oligomeric level and the polymer particles remaining after degradation. The term "to degrade completely" refers to the cleavage of the polymer at the molecular level such that there is substantially complete weight loss. The term "to degrade," as used herein, includes "complete degradation, unless otherwise indicated."

A polymer is a shape memory polymer if the original shape of the polymer is recovered by heating it above the shape recovery temperature (defined as Ttrans of the soft segment) even if the originally formed shape of the polymer is mechanically damaged at a temperature lower than the shape recovery temperature or if the remembered shape is recovered by applying a different stimulus.

As used herein, the term "segment" refers to a block or sequence of polymer forming the shape memory portion of the polymer.

As used herein, the terms hard segment and soft segment are relative terms that refer to the Ttrans of segments. The hard segment (s) have a higher Ttrans than the soft segment (s).

The shape memory polymers may include at least one hard segment and at least one soft segment, or may include at least one type of soft segment, one type of soft segment being cross-bonded without the presence of a hard segment.

The hard segments can be linear oligomers or polymers and can be cyclic compounds such as crown ethers, cyclic di-, tri- or oligopeptides and cyclic oligo (esteramides).

The physical interaction between the hard segments can be based on charge transfer complexes, hydrogen bonding, or other interactions, since certain segments have a melting point higher than the degradation temperature. In these cases, there is no melting point or glass transition point for the segment. A non-thermal mechanism, such as a solvent, is required to alter segment binding.

The weight ratio of hard segment: soft segments is between approximately 5:95 and 95: 5, preferably between 20:80 and 80:20.

PL 193 700 B1

Shape memory polymer compositions

Thermoplastic shape memory materials are shaped / formed into a desired shape above the Ttrans of the hard segment (s) and cooled to a temperature below the shape recovery temperature where the polymer may undergo mechanical deformation and deformations are generated in the polymer. The original shape of deformed polymers can be recovered by heating them to a temperature higher than their shape recovery temperature. Above this temperature, strains in the polymer are relaxed, allowing the polymer to return to its original shape. In contrast, shape memory thermosetting materials are shaped / molded into a desired shape before the macromonomers used to form the thermosetting polymers are polymerized. The macromonomers are polymerized after setting the shape.

The polymer compositions are preferably compressible by at least one percent or expandable by at least five percent of their original thickness at a temperature below the shape recovery temperature, deformation being set by the application of a stimulus such as heat, light, ultrasound, magnetic fields, or electric fields. In some embodiments, the materials exhibit a recovery ratio of 98% (compare experimental examples).

When considerable stress is applied, resulting in forced mechanical deformation at a temperature lower than the shape recovery temperature, the deformation is retained in the soft segments or amorphous regions and a large change in shape is maintained even after the stress is partially relieved by polymer elasticity. If the molecular chain configuration is disturbed by the effect of the regulated ordering of the molecular chains at a temperature lower than the glass transition temperature, the molecular chain reordering is assumed to occur by increasing the volume size and reducing the free volume content. The original shape is recovered by shrinking the hard segment aggregates by raising the temperature according to stringent chain conformation control and the polymer shape is restored to the remembered shape.

In addition to the changes from solid to liquid (melting point or glass transition temperature), the hard and soft segments may undergo solid to solid transformation and may be subject to ionic interactions involving polyelectrolytic segments or supermolecular effects based on highly organized hydrogen bonds. SMP can undergo solid-state transformations (e.g. change in morphology). Solid to solid conversions are well known to those skilled in the art, for example, as in poly (styrene-butadiene block).

Various changes to the structure of an object formed using shape memory polymers can take place. If the objects are three-dimensional, the shape changes can be two-dimensional. If the objects are essentially two-dimensional objects, such as fibers, then the shape variations will be one-dimensional, such as along the length. The thermal and electrical conductivity of materials can also change in response to changes in temperature.

The moisture permeability of the composition can be varied, especially when the polymer is formed into a thin film (ie, less than about 10 µm). Certain polymer compositions, in their original shape, have sufficient permeability such that the water vapor molecules can be transmitted through the polymer film, while the water molecules are not large enough to penetrate the polymer film. The resulting materials have low moisture permeability at temperatures below room temperature and high moisture permeability at temperatures above room temperature.

Stimuli other than temperature may be used to induce shape changes. As described below in relation to certain embodiments, the changes in shape can be induced by exposure to light or an agent such as an ion that changes the interpolymer bonds.

I. Polymer segments

The segments are preferably oligomers. As used herein, the term "oligomer" refers to a linear chain molecule having a molecular weight up to 15,000 Daltons.

The polymers are selected based on the desired glass transition temperature (s) (if at least one segment is amorphous) or melting point (s) (if at least one segment is crystalline), which in turn is based on the desired applications, taking into account the environment application. Preferably, the average molecular weight number of the polymer segment is greater than 400, and preferably ranges between 500 and 15,000.

PL 193 700 B1

The transition temperature at which the polymer suddenly softens and deforms can be controlled by changing the monomer composition and the type of monomer, allowing the shape memory effect to be adjusted at the desired temperature.

The thermal properties of the polymers can be detected, for example, by dynamic mechanical thermoanalysis or differential scanning calorimetry (DSC) studies. In addition, the melting point can be determined using standard melting point apparatus.

1. Thermosetting or thermoplastic polymers

The polymers can be thermosetting or thermoplastic polymers, although thermoplastic polymers may be preferred for their ease of molding.

Preferably, the degree of crystallinity of the polymer or polymer block (s) is between 3 and 80%, more preferably between 3 and 60%. When the degree of crystallinity is greater than 80%, while all the soft segments are amorphous, the resulting polymer composition has unsatisfactory shape memory characteristics.

The tensile strength of polymers below Ttrans is typically between 50 Mpa and 2 Gpa (gigapascals), while the tensile strength of polymers above Ttrans is typically between 1 and 500 Mpa. Preferably, the ratio of modulus of elasticity above and below Ttrans is 20 or more. The higher the ratio, the better the shape memory of the resulting polymer composition.

The polymer segments can be natural or synthetic, although synthetic polymers are preferred. The polymer segments may or may not be biodegradable, although the resulting SMP composition is biodegradable, biocompatible polymers are particularly preferred for medical applications. Generally, these materials degrade by hydrolysis, by exposure to water or enzymes under physiological conditions, by surface erosion, by mass erosion, or combinations thereof. The non-biodegradable polymers used in medical applications preferably do not include aromatic groups other than those present in the naturally occurring amino acids.

Representative natural polymer segments or polymers include proteins such as zein, modified zein, casein, gelatin, gluten, serum albumin, and collagen, and polysaccharides such as alginate, celluloses, dextrans, pullulan, and polyaluronic acid, as well as chitin, poly (3-hydroxyalkanoate). ) y, especially poly (e-hydroxybutyrate), poly (3-hydroxyoctanoate) and poly (3-hydroxy fatty acids).

Representative natural biodegradable polymer segments or polymers include polysaccharides such as alginate, dextran, cellulose, collagen, and chemical derivatives thereof (substitutions, additions of chemical groups, e.g., alkyl, alkylene, hydroxylations, oxidations, and other modifications routinely performed by those skilled in the art. in this field) and proteins such as albumin, zein, copolymers and combinations thereof, alone or in combination with synthetic polymers.

Representative synthetic polymer blocks include polyphosphazenes, polyvinyl alcohols, polyamides, polyester amides, poly (amino acid (s)), synthetic poly (amino acids), polyanhydrides, polycarbonates, polyacrylates, polyalkylenes, polyacrylamides, polyalkylene glycols, polyalkylene oxides , polyorthoesters, polyvinyl ethers, polyvinylesters, polyvinyl halides, polyvinylpyrrolidone, polyesters, polylactides, polyglycolides, polysiloxanes, polyurethanes and their copolymers.

Examples of suitable polyacrylates include poly (methyl methacrylate), poly (ethyl methacrylate), poly (butyl methacrylate), poly (isobutyl methacrylate), poly (hexyl methacrylate), poly (isodecyl methacrylate), poly (lauryl methacrylate), poly (phenyl methacrylate) ), poly (methyl acrylate), poly (isopropyl acrylate), poly (isobutyl acrylate), poly (octadecyl acrylate).

Synthetically modified natural polymers include cellulose derivatives such as alkyl celluloses, hydroxyalkyl celluloses, cellulose ethers, cellulose esters, nitrocelluloses, and chitosan. Examples of suitable cellulose derivatives include methyl cellulose, ethyl cellulose, hydroxypropyl cellulose, hydroxypropyl methyl cellulose, hydroxybutyl methyl cellulose, cellulose acetate, cellulose propionate, cellulose acetate butyrate, cellulose acetate phthalate, sodium carboxymethyl cellulose and cellulose tri cellulose. They are collectively referred to herein as "celluloses."

Representative synthetic degradable polymer segments include polyhydric acids such as polylactides, polyglycolides, and copolymers thereof; poly (ethylene terephthalate); poly (hydroxybutyric acid); poly (hydroxyvaleric acid); poly [lactide-co-feta-caprolactone)]; poly [glycolide- (ε-caprolactone)]; polycarbonates, poly (pseudoamino acids); poly (amino acids); poly (hydroxyalkanoate) y; polyanhydrides; polyorthoesters and their kits and copolymers.

PL 193 700 B1

Examples of non-biodegradable synthetic polymer segments include ethylene vinyl acetate, poly (meth) acrylic acid, polyamides, polyethylene, polypropylene, polystyrene, polyvinyl chloride, polyvinylphenol, and copolymers and mixtures thereof.

Rapidly bioerodible polymers such as poly (lactide-co-glycolide) y, polyanhydrides and pliorthoesters, which have carboxyl groups exposed to the exterior surface when the smooth surface of the polymer erodes, may also be used. Moreover, polymers containing labile bonds such as polyanhydrides and polyesters are well known for their hydrolytic reactivity. Their rates of hydrolytic degradation can essentially be altered by simple changes to the polymer backbone and their sequence structure.

Various polymers such as polyacetylene and polypyrrole are conductive polymers. These materials are particularly preferred for applications where electrical conductivity is important. Examples of these applications include tissue engineering and biomedical applications where cell growth is to be stimulated. These materials can find particular utility in the field of computing as they are better able to absorb heat without increasing temperature than SMA. Conductive shape memory polymers are useful in the field of tissue engineering for promoting the growth of tissue, e.g., nervous tissue.

2. Hydrogels

The polymer may be in the form of a hydrogel (typically absorbing up to about 90% by weight of water) and may optionally be ionically crosslinked to polyvalent ions or polymers. Ionic crosslinks between soft segments can be used to maintain a structure that, when deformed, can be reformed by breaking the ionic crosslinks between soft segments. The polymer may also be in the form of a gel in solvents other than water or in aqueous solutions. In these polymers, the temporary shape can be set by the hydrophilic interaction between the soft segments.

Hydrogels can be formed from polyethylene glycol, polyethylene oxide, polyvinyl alcohol, polyvinyl pyrrolidone, polyacrylates, polyethylene terephthalate, polyvinyl acetate, and copolymers and kits thereof. Some polymer segments, for example acrylic acid, are elastomeric only when the polymer is hydrated and hydrogels are formed. Other polymer segments, e.g., methacrylic acid, are crystalline and capable of melting even when the polymers are not hydrated. Any polymer block can be used depending on the desired application and the conditions of use.

For example, shape memory is observed in acrylic acid copolymers only in the hydrogel state because the acrylic acid units are substantially hydrated and behave like a soft elastomer with a very low glass transition temperature. Dry polymers are not shape memory polymers. When dry, the acrylic acid units behave like a hard plastic even above the glass transition temperature and show no sudden change in mechanical properties when heated. In contrast, copolymers containing methyl acetate polymer segments as soft segments exhibit shape memory properties even when dry.

3. Polymers capable of forming gels at elevated temperatures.

Certain polymers, for example poly (ethylene oxide-propylene co-oxide) (PLURONICS ™), are water-soluble at temperatures lower than body temperature and become hydrogels at temperatures higher than body temperature. Incorporating these polymers as segments into shape memory polymers enables shape memory polymers to respond to temperature changes in a manner contrary to conventional shape memory polymers. These materials regain their shape when cooled below their shape recovery temperature rather than being heated above their shape recovery temperature. This effect is called the inverse thermal shape memory effect. Shape memory polymer compositions including these polymer segments are useful in a variety of biomedical applications where the polymer may be inserted as a liquid and cooled to recover its intended shape on site. The inverse thermal shape memory effect can be obtained by including in the polymer two different segments which are miscible at temperatures lower than the Tmisc (Tmisc) but are immiscible at higher temperatures. Phase separation at higher temperatures stabilizes the temporary shape.

The polymers can be obtained from commercial sources such as Sigma Chemical Co., St. Louis, MO .; Polysciences, Warrenton, PA; Aldrich Chemical Co., Milwaukee, WI; Fluka, Ronkonkoma, NY and BioRad, Richmond, CA. Alternatively, the polymers can be synthesized from monomers obtained from commercial sources using standard techniques.

PL 193 700 B1

II. Installation of polymer segments

The shape memory polymer comprises one or more hard segments and one or more soft segments, at least one of the segments being biodegradable or at least one of the segments being linked to another segment by a biodegradable bond. Representative biodegradable linkages include ester, amide, anhydride, carbonate, or ortho ester linkages.

1. Polymer structures.

The shape memory effect is based on the morphology of the polymer. With regard to thermoplastic elastomers, the original shape of the object is determined by the physical crosslinks caused by the hard segment. With regard to thermosetting polymers, the soft segments are covalently cross-linked instead of having hard segments. The original shape is set by a transverse linkage process.

Unlike prior art segmented polyurethane SMPs, the segments of the compositions described herein need not be linear. The segments may be partially grafted or attached to the dendritic side groups.

A. Thermoplastic and thermoelastic polymers

The polymers can be in the form of linear two-block, tri-block, four-block or multi-block polymers, branched or grafted polymers, thermoplastic elastomers that contain dendritic structures, and combinations thereof. Fig. 3 illustrates some combinations of the respective classes of thermoplastic materials to form hard and soft segments. The shape memory thermoplastic polymer composition may also be a batch of one or more homo or co-polymers with one or more diblock, triblock, fourblock or multiblock copolymers, branched or grafted polymers. These types of polymers are well known to those skilled in the art.

As used herein, the term "degradable thermosetting material" refers to (i) thermosetting SMPs that contain cleavable bonds and (ii) thermosetting materials containing more than one soft segment with at least one soft segment being degraded or different soft segments. they are connected by cleavable bonds. There are four different types of thermosetting polymers that have shape memory capability. These include polymer networks, interpenetrating networks, interpenetrating networks, and mixed interpenetrating networks.

i. Polymer networks

The polymer network is prepared by a covalent crosslink of macromonomers, i.e. polymers that contain polymerizable end groups such as carbon-carbon double bonds. The polymerization process can be triggered by the use of light or heat sensitive initiators or by curing with ultraviolet light without an initiator. The shape memory polymer networks are prepared by cross-linking one or more soft segments that respond to one or more thermal transitions.

In an embodiment recommended for medical applications, the crosslinking is accomplished using a transverse linkage and does not require any chemical initiator. The photo crosslink advantageously eliminates the need for initiator molecules which may be toxic. Fig. 4 is a reaction sequence diagram for the synthesis of a preferred cross photo linkage which produces a total reaction yield of about 65%.

ii. Intertwining networks

Intersecting Networks ("IPNs") are defined as networks where the two components are cross-linked but not related to each other. The original shape is determined by the network with the highest cross-link density and the highest mechanical strength. The material has at least two Ttrans corresponding to different soft segments of both networks.

iii. Mixed networks interpenetrating each other

A mixed ALS comprises at least one physically cross-linked polymer network (thermoplastic polymer) and at least one covalently cross-linked polymer network (thermosetting polymer), which cannot be separated by any physical means. The original shape is fixed by a covalently cross-linked lattice. The temporary shapes correspond to the Ttrans of the soft segments and the Ttrans of the hard segment of the thermoplastic elastomer component.

A particularly preferred mixed interpenetrating network is prepared by polymerizing a reactive macromonomer in the presence of a thermoplastic polymer, for example,

By photopolymerization of carbon-carbon double bonds. In this embodiment, the weight ratio of thermosetting polymer to thermoplastic polymer is preferably between 5:95 and 95: 5, more preferably between 20:80 and 80:20.

iv. Mutually interpenetrating networks

Interconnecting networks ("semi-IPNs) are defined as two independent components, where one component is a cross-linked polymer (polymer network) and the other component is a non-cross-linked polymer (homopolymer or copolymer), and the components cannot be separated by methods. physical. The interpenetrating network has at least one thermal transition corresponding to the soft segment (s) and the homo- or copolymer components. The cross-linked polymer preferably comprises between about 10 and 90% by weight of the interpenetration network composition.

v. Polymer kits

In a preferred embodiment, the shape memory polymer compositions described herein are formed from a biodegradable polymer composition. As used herein, "a biodegradable polymer kit is a kit having at least one biodegradable polymer.

Shape memory polymers can exist as physical mixtures of thermoplastic polymers. In one embodiment, the shape memory polymer composition can be prepared by interacting or blending two thermoplastic polymers. The polymers can be semi-crystalline homopolymers, semi-crystalline copolymers, thermoplastic elastomers with linear chains, thermoplastic elastomers with side chains or any type of dendritic structural elements and branched copolymers, and they can be assembled in any combination thereof.

For example, a hard segment copolymer with a relatively high Ttrans and a soft segment with a relatively low Ttrans may be blended or blended with a second multiblock copolymer with a hard segment with a relatively low Ttans and the same soft segment as the first multiblock copolymer. The soft segments in both multi-block copolymers are identical, so the polymers are miscible with one another when the soft segments are melted. There are three transition temperatures in the resulting set, that of the first hard segment, that of the second hard segment, and that of the soft segment. Accordingly, the materials are capable of remembering two different shapes. The mechanical properties of these polymers can be controlled by varying the weight ratio of the two polymers.

Other types of batch of at least two multi-block copolymers can be prepared in which at least one of the segments is mixed with at least one of the segments of the other multi-block copolymers. If two different segments are miscible and constitute one domain together, then the thermal transition of that domain depends on the weight content of the two segments. The maximum number of shapes saved is derived from the number of thermal transitions in the set.

Shape memory kits may have better shape memory capabilities than the kit components alone. Shape memory blends are composed of at least one multi-block copolymer and at least one homo- or copolymer. In principle, two-, three- or four-block copolymers can be used in place of the multi-block copolymer.

Shape memory blends are highly useful in industrial applications because a wide range of mechanical, thermal and shape memory capabilities can be obtained from only two or three primary polymers by blending them at different weight ratios. A twin screw extruder is an example of standard process equipment that can be used to mix ingredients and process the batch.

III. Ways of making SMP

The polymers described above are either commercially available or can be synthesized using methods known to those skilled in the art. Examples 1 and 2 below show the experimental procedures for the preparation of SMP.

IV. Ways of shaping SMP compositions

These compositions may be formed into a first shape according to suitable conditions, for example at a temperature above the Ttrans of the hard segment (s), and cooled below the Ttrans of the soft segment (s). Standard techniques are extrusion and injection molding. Optionally, the item may be remoulded into a second shape. Under the influence of heat or some other appropriate set of factors, the object returns to its original shape.

PL 193 700 B1

Thermosetting polymers can be prepared by extruding the pre-polymerized material (macromonomers) and setting the original shape at a temperature above the Ttrans of the thermosetting polymer, for example by photo-curing reactive groups on the monomer.

The temporary shape is fixed by cooling the material below Ttrans after deforming the material.

The Fig. Illustrates the photo-induced shape memory effect.

The crosslinking can also be performed in a macromonomer solution, with the solvent being removed from the gel formed in the next operation.

Compositions made from thermoplastic polymers can be blown, extruded into sheets, or shaped by injection molding, for example, to form fibers. These compositions can also be shaped by other methods known to those skilled in the art to shape solid objects, for example, laser removal, micromachining, machining, hot wire and CAD / CAM (computer aided design / manufacturing) processes. These processes are recommended for the shaping of thermosetting polymers.

V. Therapeutic, prophylactic and diagnostic applications

Any of a wide variety of therapeutic, prophylactic, and diagnostic agents can be incorporated within the polymer compositions that can deliver the incorporated agents locally or systemically when administered to a patient.

Examples include synthetic inorganic and organic compounds or molecules, proteins and peptides, polysaccharides and other sugars, lipids, and nucleic acid molecules having therapeutic, prophylactic, and diagnostic effects.

Nucleic acid molecules include genes, plasma DNA, bare DNA, anti-sensory molecules that bind to complementary DNA to suppress transcription, ribozymes, and ribozyme guide sequences. Due to the variety of biological activities, we can distinguish active vascular agents, neuroactive agents, hormones, growth factors, cytokines, anesthetics, steroids, anticoagulants, anti-inflammatory agents, immunomodulating agents, cytotoxic agents, prophylactic agents, antibiotics, antiviral agents, antisensory agents, antigens and antibodies. In some instances, the proteins may be antibodies or antigens that would otherwise need to be administered by injection to elicit an appropriate response.

Proteins are defined as consisting of the remaining 100 amino acids or more; peptides are residues of less than 100 amino acids. Unless otherwise stated, the term protein refers to both proteins and peptides. Polysaccharides such as heparin may also be administered. Compounds with a wide range of molecular weights, for example between 10 and 500,000 grams per mole, can be encapsulated.

Also mention may be made of commercially available imaging agents that can be used in positron emission tomography (PET), computer assisted tomography (CAT), computerized single-photon emission tomography, x-rays, fluoroscopy, magnetic resonance imaging (MRI) and ultrasound media.

VI. Articles, devices and coatings

The SMP compositions may also be used in biomedical and other applications.

1. Articles and devices for medical use

Examples of such applications are sutures, orthodontic materials, bone screws, nails, plates, catheters, tubes, films, patency tubes, orthopedic braces, splints, cast preparation tape, tissue engineering scaffolds, contact lenses, drug delivery devices, implants and indicators thermal.

SMP compositions are preferably made of biocompatible polymers and, for most applications, biodegradable polymers, the rate of degradation may be controlled depending on the nature of the composition and the crosslinking of the polymer. Biodegradable polymer implants eliminate the need for implant recovery and can be used concurrently to deliver therapeutic agents.

These materials can be used in a variety of applications requiring load bearing capacity and controlled degradation.

The polymer compositions can also be molded to the shape of the implant to be implanted inside the body to perform a mechanical function. Examples of such implants include rods, pins, screws, plates, and anatomical shapes.

PL 193 700 B1

A particularly preferred use of the compositions is in the preparation of sutures that are quite stiff to allow easy insertion, but which soften upon reaching body temperature and form a second shape that is more comfortable for the patient during further treatment.

Another preferred use is for catheters, which should be rigid below body temperature for easier insertion and softened when warmed to body temperature to provide patient comfort.

The polymer compositions can also be combined with fillers, reinforcement materials, radioimaging materials, excipients or other materials as needed for a particular implant application. Examples of fillers include sodium calcium metaphosphate, which is described in US Patent No. 5,108,755. Those skilled in the art can readily determine the appropriate amount of these materials to be included in a composition.

The articles may incorporate a variety of therapeutic and / or diagnostic agents, as described above.

2. Non-medical applications

There are numerous applications for shape memory polymer compositions other than biomedical applications.

Examples of non-medical type applications for biodegradable polymers include items where disposal is a concern, such as disposable diapers and sanitary napkins, and packaging materials.

3. Coatings with controlled degradation

Shape memory polymers can be designed so that the rate of degradation is variable. For example, in one embodiment, the hydrolytically degradable polymer may be selectively protected by applying a hydrophobic SMP coating to temporarily prevent water from entering the hydrolytically cleavable bonds of the polymer mass. The protective feature of the coating can then be modified as desired by applying an external stimulus such that the diffusion properties of the coating are altered allowing water and other aqueous solutions to permeate through the coating and initiate the degradation process. If the rate of hydrolysis is relatively high compared to that of water, then the rate of water diffusion through the coating determines the rate of degradation. In another embodiment, a hydrophobic coating consisting of densely cross-linked soft segments can be used as a diffusion barrier for water or aqueous solutions. The soft segments should be at least partially cross-linked by bonds that can be cleaved by the application of a stimulus. The diffusion rate of water can be increased by lowering the cross-link density.

VII. Application methods

Certain articles are manufactured to maintain their intended shape as long as they do not function incompatible with their normal use. For example, a car bumper will maintain its intended shape until it is struck. These manufactured articles are to be used as intended and repaired, for example by applying heat, once they have been damaged.

Other articles of manufacture are designed to be used such that the first shape is intended for primary use and the second shape is intended for subsequent use. Examples of these articles include biomedical devices that can form a second shape when body temperature is reached or when an external stimulus is applied that warms the device above body temperature.

Still other articles produced are designed to be used such that their shape changes in response to or regulated according to changes in temperature, such as thermal sensors in medical devices.

The present invention will be better understood on the basis of the following non-limiting examples.

Example 1: Copolyestrethane shape memory polymers

A group of biocompatible and biodegradable multi-block copolymers exhibiting a thermal shape memory effect has been synthesized. These polymers were composed of a crystallizable hard segment (Tm) and a soft segment having a thermal transition temperature Ttrans between room temperature and body temperature. Unlike prior art segmented polyurethanes, the hard segment was an oligoester or oligoether ester and did not contain an aromatic component.

PL 193 700 B1

The mechanism for programming the temporary shape and recovering the shape of the solid block copolymer is shown in Fig. 6. The solid shape of the materials was established by melting the polymer and cooling the above Ttrans (Fig. 6 top position). The polymer was then formed into its temporary shape (Fig. 6, pos. Right), which was fixed by cooling below Ttrans (Fig. 6, pos.

lower). After unloading, the solid shape was recovered by heating above Ttrans.

Synthesis of telechels, oligomers with functional groups at both ends

Telechelic macrodiol was synthesized by ring-opening polymerization of cyclic monomers with di (n-butyl) tin oxide as a transesterification catalyst under N2 atmosphere.

The hard segment α, O-dihydroxy [oligo (ethylene glycol glycolate) ethylene oligo (ethylene glycol glycolate)] - (PDS1200 and PDS1300) was prepared as follows. The p-dioxane-2-one monomer was obtained by distillation (thermal depolymerization) of the oligomer prior to use. 57 g (0.63 mol) of monomer, 0.673 g (10.9 mmol) of ethylene glycol and 0.192 g (0.773 mmol) of di (n-butyl) tin oxide was heated to 80 ° C for 24 h. End of reaction (equilibrium) was determined by GPC. The product was dissolved in hot 1,2-dichloroethane and filtered hot through a Buechner funnel filled with silica gel.

The product was obtained by precipitation in hexanes and dried in vacuo for 6 h.

Soft segment

i. Crystalline

Polyphaprolactone) diols with different M _n are commercially available from e.g. Aldrich and Polysciences. Here, PCL-2000 was used.

ii. Amorphous α, β-dihydroxy [oligo (L-lactane-co-glycolate) ethylene oligo (L-lactane-co-glycolate) - (abbreviation: PLGA2000-15) was prepared as follows. In a 1000 mL double-necked round bottom flask, 300 g (2.08 mol) L, L-diclactide, 45 g (0.34 mol) diglycolide, and 4.94 g (0.80 mol) ethylene glycol were heated to melt in 40 ° C and mixed. 0.614 g (2.5 mmol) of di (n-butyl) tin oxide was added. After 7 h the reaction had equilibrated as determined by GPC. The reaction mixture was dissolved in 1,2-dichloroethane and purified on a silica gel column. The product was obtained by precipitation in hexanes and dried in vacuo for 6 h.

Properties of telechelikes

The molecular weight Mn and the thermal properties of the macrodiols were determined as shown in Table 1 below.

T a b e l a 1:

Molecular mass and thermal properties of macrodiols

Label Mn GPC [g-mol ^-1 ] MnVPO [g-mol ^-1 ] Tm [° C] ΔΗ [Jg ^-1 ] 1 st ΔCp [Jg ^-1 ] PCL2000 1980 1690 43 73.5 <-40 - PDS1300 1540 1340 97 74.5 <-20 - PDS1200 2880 1230 95 75.0 <-20 - PLGA2000 2020 1960 - - 29.0 0.62

Synthesis of thermoplastic elastomers (multi-block copolymer)

In a 100 ml two-necked round bottom flask connected to a Soxhlet extractor filled with a 0.4 nm molecular sieve, two different macrodiols (one hard segment and one soft segment) as described in Table 2 below were dissolved in 80 ml of 1,2-dichloroethane . The mixture was flowed back to dry by azeotropic extraction from the solvent. Freshly distilled trimethylhexane-1,6-diisocyanate was added via syringe and the reaction mixture was heated to 80 ° C for at least 10 days. At regular intervals, samples of the mixture were taken to determine the molecular weight of the polymer by GPC. At the end of the reaction, the product was obtained by precipitation of the polymer in hexanes and purification by redissolving in 1,2-dichloroethane and precipitation in hexanes.

The multi-block copolymers were prepared from the following two types of polymers.

(I) PDC polymers contain polyphaprolactone). T _trans for the soft segment is the melting point.

(ii) PDL polymers contain α, ff > -dihydroxy [oligo (L, -lactane-co-glycolate) ethylene oligo (? -lactane-co-glycolate). Ttrans for the soft segment is the glass transition temperature.

T a b e l a 2:

Synthesis of multi-block copolymers

Polymer 1. Diol m [g] n [mmol] 2. Diol m [g] n [mmol] TMDI [mmol] time [days] PDC22 PDS1200 3.0245 2.653 PCL2k 6.0485 3.024 5.738 10 PDL23 PDS1200 2.2787 2,000 PLGA2k 6.1443 3.070 5.163 10 PDC27 PDS1300 2.5859 1.724 PCL2k 5.3611 2.681 4.368 14 PDC40 PDS1300 3.6502 2.433 PCL2k 3.9147 1.957 4.510 13 PDC37 PDS1300 3.2906 2,194 PCL2k 4.8619 2.431 4,500 16 PDL30 PDS1300 3.7115 2.474 PLGA2k 4.0205 2.011 4.480 16

Properties of thermoplastic elastomers

The physical, mechanical, and degradation properties determined for the compositions are given in Tables 3-9 below.

The hydrolytic degradation behavior of the new materials was tested in a pH 7 buffer solution at 37 ° C. It has been shown that the polymers are completely degradable and the rate of their degradation can be controlled by the concentration of easily hydrolysable ester bonds. Relative mass loss values mr = m (t0) / m (t) in% at 37 ° C and relative molecular weight loss Mr = Mw (t) / M (t0) in% at 37 ° C.

The toxicity of two different multi-block copolymers was tested using the chicken egg test. It was shown that the blood vessels developed regularly and the polymer samples did not affect their condition.

T a b e l a 3:

The composition of the copolyester urethanes defined spektroskopią- ¹ H-NMR 400 MHz

Label Hard segment Mass content [%] * Soft segment Mass content [%] * PDL23 PDS 23.0 PLGA 54.2 PDL30 PDS 30.0 PLGA 52.1 PDC22 PDS 22.0 PCL 64.5 PDC27 PDS 27.0 PCL 61.1 PDC37 PDS 31.1 PCL 55.4 PDC40 PDS 40.4 PCL 46.2

* There is a difference of up to 100% in urethane content

PL 193 700 B1

T a b e l a 4:

Molecular mass Mm of copolyester urethane films determined by multidetector-GPC

Label Polymer film Mw (LS) [g-mol ^-1 ] Mw (Visc) [g-mol ^-1 ] dn / dc [g-mol ^-1 ] PDL23 161,500 149,000 0.065 PDL30 79,100 83,600 0.057 PDC22 119.900 78,500 0.078 PDC27 72,700 61,100 0.080 PDC31 110,600 108,600 0.065 PDC40 93,200 86.300 0.084

T a b e l a 5:

Transition temperatures Tm and Tg, melting enthalpies \ H _TI and change in heat capacity Δcp of the polymer film from DSC

Measurements (values given from the second heating process) Label Έ o and- ΔHm1 [Jg ^-1 ] Tg [° C] ΔCp [Jg ^-1 ] Tm ² [ ^o C] \ Hm2 [Jg ^-1 ] PDL23 - - 34.5 0.38 - - PDL30 - - 33.5 0.25 85.0 8.5 PDC22 35.0 26.0 - - - - PDC27 37.0 25.0 - - 75.5 3.5 PDC31 36.5 28.5 - - 76.5 5.5 PDC40 35.0 7.0 - - 77.5 7.0

T a b e l a 6:

Mechanical properties of polymer films at 50 ° C from tensile tests

Code Module E [Mpa] Or [%] σρ [Mpa] smax [%] cmax [Mpa] PDL27 1.5 1,350 2.1 1,300 2.3 PDC31 1.5 1,400 4.9 1,300 5.4 PDC40 4.0 1,250 5.8 1,300 5.9 PDL30 2.0 1,400 2.1 1,250 2.3

T a b e l a 7: Degradability of PDL22

Degradation time [days] Mr (viscometry) [%] Mr (light scattering) [%] 14 81.3 85.7 21 67.1 74.6 29 62.9 65.6 42 43.6 47.7 56 54.4 41.9

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T a b e l a 8: Degradability of PDL23

Degradation time [days] Mr (viscometry) [%] Mr (light scattering) 14 61.1 87.3 21 40.7 76.7 29 32.8 62.2 42 17.4 46.7 56 16.9 18.7

T a b e l a 9: Loss of relative mass

PDC22 PDL23 Degradation time [days] m _y [%] m _y [%] 14 99.2 98.1 21 99.3 97.5 29 98.6 97.2 42 98.3 96.9 56 97.3 93.3

Shape memory properties

Fig 7 shows the results of tensile tests performed on multi-block copolymers as a function of thermolytic cycles. The average rate of formation of the shape of thermocyclic treated polymers and the relationship of the strain removal rate as a function of the number of cycles are shown below in Tables 10 and 11, respectively. The polymers have high shape fixation and equilibrium was achieved after only two cycles.

T a b e l a 10:

Average rate of fixing the shape of Rf

Label Rf [%] PDC27 97.9 PDC40 96.2 PDL30 97.7

T a b e l a 11:

The dependence of the number of cycles on the rate of deformation removal Rr

PDC27 PDC40 PDL23 Number of cycles Yy [%] Yy [% 1] Yy [%] 2 77.3 73.7 93.8 3 93.2 96.3 98.8 4 98.5 98.7 98.9 5 98.5 98.7 98.8

Example 2: Degradable Shape Memory Thermoset Material with Soft Crystallizable Segment

A certain range of polyphe-caprolactone) dimethacrylates and thermosetting materials has been evaluated with respect to mechanical properties and shape memory.

PL 193 700 B1

Synthesis of the macromonomer

Polyphe-caprolactone) dimethacrylates (PCLDMA) were prepared as follows. To a solution of polyphe-caprolactone) diol with M _n = 2'000 mol ^-1 (20.0 g, 10 mmol) and triethylamine (5.3 ml, 38 mmol) in 200 ml of dry THF, chloride was added dropwise at 0 ° C methacryloyl (3.7 mL, 38 mmol). The solution was stirred at 0 ° C for 3 days and the precipitated salt was filtered off. After concentrating the mixture at room temperature under reduced pressure, 200 mL of ethyl acetate was added and the solution was filtered again and precipitated into a tenfold excess of a mixture of hexanes, diethyl ether and methanol (18: 1: 1). The colorless precipitation was collected, dissolved in 200 ml of dichloroethane, precipitated again and dried thoroughly at room temperature under reduced pressure.

Synthesis of thermosetting materials

The macromonomer (or monomer mixture) was heated to 10 ° C above its melting point (Tm) and placed in a mold formed by two glass plates (25mm x 75mm) and a 0.60mm Teflon spacer. To achieve good homogeneity, the mold was stored at Tm for a further hour. Photo-curing was performed on a heated plate at Tm for 15 min. The distance between the heat lamp head and the sample was 5.0 cm. After cooling to room temperature, a sample was withdrawn and swelled with a 100-fold excess of dichloromethane overnight and washed thoroughly. Finally the sample was dried at room temperature under reduced pressure.

Properties of macromonomers and thermosetting materials

Table 12 below shows the polyphaprolactone) dimethacrylates that were prepared as well as the corresponding degree of acrylation (Da) (%). The number following PCLDMA is the molecular weight Mn polyhaloC-caprolactone) diol used in the synthesis as determined using ^H-12 NMR and GPC, rounded to 500.

T a b e l a 12:

Poly (? -Caprolactone) diol and degree of acrylation

Name Da [%] PCLDMA1500 87 PCLDMA2000 92 PCLDMA3500 96 PCLDMA4500 87 PCLDMA6500 93 PCLDMA7000 85 PCLDMA10000 86

Fig. 8 shows the melting point (Tm) of diols, dimethacrylates and polyphaprolactone thermosetting materials as a function of the molar mass of M _n macromonomers. In the diagram, macrodioles are represented by ----; macromonomers by ....... and thermosetting materials by - ▲ Tensile properties of polyphe-caprolactone thermosets) C1 to C7 at room temperature are shown below in table 13, where E is the modulus of elasticity (Young's modulus), _ε,; is the elongation a σ .; is the yield stress, and _max is the maximum stress, ε _π3χ is the elongation at σ _π3χ , ε _κ is the elongation at failure and σ _β is the stress at failure. Table 14 below shows the tensile properties of the same polyphaprolactone thermosetting materials at 70 ° C.

PL 193 700 B1

T a b e l a 13:

Tensile properties of thermosetting materials at room temperature

Name E [MPa] εs [%] σs [MPa] ^ ax ^[ % ^] G’max [MPa] εR [%] σ _R [MPa] Cl 2.4 + 0.6 - - 16.1 ± 2.0 0.4 ± 0.1 16.1 ± 2.3 0.38 + 0.02 C2 35 ± 3 - - 20.6 ± 0.3 4.7 ± 0.1 20.6 + 0.3 4.7 + 0.1 C3 38 ± 1 48 ± 1 11.2 ± 0.1 180 + 20 12.1 ± 1.2 190 ± 20 11.7 ± 1.6 C4 58 ± 4 54 ± 1 12.2 ± 0.1 247 ± 4 13.6 + 1.9 248 ± 13 15.5 ± 2.7 C5 7211 56 ± 2 15.5 ± 0.2 275 ± 10 15.6 + 1.7 276 ± 6 15.0 ± 1.0 C6 71 ± 3 43 ± 2 14.2 + 0.1 296 ± 14 15.5 ± 0.2 305 ± 8 13.8 ± 2.7 C7 71 ± 2 42 ± 5 13.6 ± 0.2 290 ± 30 16.2 ± 0.5 290 ± 30 15.7 ± 0.9

T a b e l a 14:

Tensile properties of thermosetting materials at 70 ° C

Name E [MPa] G’max [MPa] εR [%] Cl 1.84 + 0.03 0.40 ± 0.08 24 ± 6 C2 2.20 ± 0.12 0.38 ± 0.05 18 ± 2 C3 6.01 + 0.12 2.05 ± 0.21 43 ± 9 C4 2.30 ± 0.16 0.96 ± 0.01 61 ± 3 C5 1.25 ± 0.08 0.97 ± 0.15 114 ± 13 C6 1.91 ± 0.11 1.18 ± 0.06 105 ± 11 C7 0.70 ± 0.09 0.79 ± 0.10 210 ± 7

Shape memory properties

It was determined that the thermosetting materials should have the thermomechanical properties indicated in Table 15. The molecular weight average number (Mn) refers to the macromonomer. The lower limit temperature, T1, is 0 ° C and the higher limit temperature, Th, is 70 ° C. The stretch of the temporary shape is 50%. Rr (2) is the second cycle strain regeneration rate, Rr, tot is the total 2 cycle strain recovery rate, Rf is the average set strain rate.

T a b e l a 15:

Thermomechanical properties of thermosetting materials

Name Mn [g-mol ^-1 ] Ry (2) [%] Rr, tot [%] Rf [%] C4 4,500 93.3 93.0 93.9 + 0.2 C5 6,500 96.3 94.5 93.9 ± 0.2 C6 7,000 93.8 92.1 92.5 ± 0.1 C7 10,000 98.6 96.8 86.3 ± 0.5

Patent claims

Claims (19)

Patent claims A degradable shape memory polymer composition comprising at least one hard segment, the transformation temperature of which Ttrans is in the range of -40 to 270 ° C, and at least one associated with the at least one hard segment, The soft segment, the transformation temperature of which Ttrans is at least 10 ° C lower than the transformation temperature Ttrans of the hard segment (s), and at least one of the hard or soft segments has a degradable region, or at least one pair of hard and soft segments has a degradable bond. 2. A degradable composition according to Claim 1; The composition of claim 1, wherein the shape memory polymers are affected by external stimuli, especially temperature or light. 3. A degradable composition according to Claim 1; The method of claim 1 or 2, characterized in that the transformation temperature Ttrans of the hard segment is in the range from 30 to 150 ° C, preferably up to 100 ° C. 4. A degradable composition according to Claim 1; The process of claim 1 or 2, characterized in that the transformation temperature Ttrans of the soft segment (s) is at least 20 ° C lower than the transformation temperature Ttrans of the hard segment (s). 5. A degradable composition according to Claim 5; The method of claim 1 or 2, characterized in that at least one of the hard and soft segments is a thermoplastic polymer. 6. A degradable composition according to Claim 6; The method of claim 1 or 2, characterized in that cyclic portions are present in the hard segment. 7. A degradable composition according to Claim 7; The method of claim 1 or 2, characterized in that the weight ratio of the hard and soft segments is in the range from about 5: 95 to 95: 5, preferably from 20: 80 to 80:20. 8. A degradable composition according to Claim 8; The shape-memory polymer as claimed in claim 1 or 2, wherein the shape memory polymer belongs to the group consisting of graft, linear and dendritic polymers. 9. A degradable composition according to Claim 9; The method of claim 1 or 2, wherein the degradable region of the polymer belongs to the group consisting of polyhydric acids, polyester ether, polyorthoesters, polyamino acids, synthetic polyamino acids, polyanhydrides, polycarbonates, polyhydroxyalkanes, and polyphaprolactones). 10. A degradable composition according to Claim 10; The method of claim 1 or 2, wherein the polymer comprises a biodegradable bond that belongs to the group consisting of ester, carbonate, amide, anhydride and orthoester subgroups. 11. A degradable composition according to Claim 11; The composition of claim 1 or 2, characterized in that the polymer is completely biodegradable. 12. A degradable composition according to Claim 1; The method of claim 1 or 2, characterized in that it comprises a degradable thermosetting polymer which in turn comprises a crystallizing soft segment with a cross-linked covalent structure having a melting point Tm in the range of 250 ° C to (-) 40 ° C, preferably of 200 ° C. ° C to 0 ° C, or a soft segment, cross-linked covalent structure, having a transition temperature Ttrans ranging from 250 ° C to (-) 60 ° C, preferably from 200 ° C to 0 ° C. 13. A degradable composition according to Claim 1; 3. The method of claim 1 or 2, characterized in that it comprises at least two segments: a) the first segment, the transformation temperature of which Ttrans is in the range from -40 to 270 ° C, b) a second segment which is associated with at least one first segment and which is an ionic interaction of sufficient strength that the second segment is capable of forming a physical cross-link other than at the melting or glass transition temperature, at least one of the segments having a melting point. the biodegradable region or at least one of the first segments is bound to at least one of the second segments through a biodegradable bond. 14. A degradable composition according to Claim 14; The method of claim 13, wherein the ionic interaction is polyelectrolyte segments, or polyelectrolyte segments and ions, or polyanionic and polycationic segments, or supramolecular effects based on highly organized hydrogen bonds. 15. A degradable composition according to Claim 15; The polymer of claim 1 or 2, wherein the polymer has an inverted temperature effect, wherein the composition is recovered in shape upon cooling below the shape recovery temperature. 16. A degradable composition according to Claim 16; 2. A composition according to claim 1 or 2, characterized in that it comprises polymer compositions containing two-, three- or four-block copolymers and one homo- or copolymer. PL 193 700 B1 17. A degradable composition according to Claim 17; A polymer composition according to claim 1 or 2, characterized in that it contains a polymer set belonging to the group consisting of physical polymer mixtures, polymer sets containing hard segments with different transformation temperatures Ttrans and soft segments with the same transformation temperature Ttrans, sets of multi-block copolymers in which at least one of The segments of the first copolymer are miscible with at least one of the segments of the second copolymer, and sets of at least one multi-block copolymer and at least one homo- or copolymer. 18. A degradable composition according to Claim 18; The shape of any of the preceding claims, wherein the coating comprises a degradation modifying coating of the shape memory polymer. 19. The use of a degradable shape memory polymer composition as in Claim 1 for the production of technical, pharmaceutical, biomedical, cosmetic and care articles and devices, such as, for example, capsules, sutures, orthodontic materials, splints, rods, screws, nails and plates used in bone surgery, tissue engineering scaffolds, films, tubes patencyers, catheters, prostheses, transplants and implants, contact lenses, pumps and nets, light metering devices and thermal sensors, diapers, sanitary napkins and packaging, contrast agents, used, inter alia, in tomographic, resonance and x-ray examinations.