CN110591047A

CN110591047A - Degradable polyether polyurethane and preparation method thereof

Info

Publication number: CN110591047A
Application number: CN201910852980.0A
Authority: CN
Inventors: 赵俊鹏; 陈烨; 张广照
Original assignee: South China University of Technology SCUT
Current assignee: South China University of Technology SCUT
Priority date: 2019-09-10
Filing date: 2019-09-10
Publication date: 2019-12-20

Abstract

The invention belongs to the field of polyurethane materials, and discloses degradable polyether polyurethane and a preparation method thereof. Performing controllable ring-opening polymerization on an epoxy monomer by utilizing a carboxylic acid type catalysis/initiation system to synthesize esterified polyether polyol, and then mixing and reacting the esterified polyether polyol with isocyanate to prepare degradable polyether polyurethane; the obtained degradable polyether polyurethane can be degraded at a controllable rate under acidic, alkaline and biological conditions. Compared with the method of introducing ester bonds or acetals into isocyanate or a micromolecular chain extender, the method of the invention has the advantage that no extra micromolecular pre-synthesis step is needed.

Description

Degradable polyether polyurethane and preparation method thereof

Technical Field

The invention belongs to the field of polyurethane materials, and particularly relates to degradable polyether polyurethane and a preparation method thereof.

Background

Polyurethanes are collectively called Polyurethanes (PUs), and are a generic name for high molecular compounds having a repeating carbamate (-NHCOO-) group in the main chain. It is a multi-block copolymer prepared by gradually polymerizing organic diisocyanate or polyisocyanate and dihydroxy or polyhydroxy compound, and has the characteristics of easy molecular structure design and adjustable performance.

The molecular chain of polyurethane can be generally divided into a soft segment and a hard segment, wherein the soft segment is composed of soft segments with the glass transition temperature lower than room temperature, and the hard segment is composed of rigid segments with the glass transition temperature higher than room temperature. Soft segments are typically macromolecular polyethers, polyesters, polycarbonates, and the like. The performances of high elasticity, wear resistance, weather resistance and the like of the polyurethane material are determined by the flexibility of a soft molecular chain. The hard polyurethane segment is composed of isocyanate and diol/diamine with small molecular weight, usually has strong polarity, and a large number of hydrogen bonds can be formed among molecular chains, and exist in an aggregation state, so that the hardness, strength, heat resistance and the like of the polyurethane material are controlled. The characteristics of diversified structures, excellent performance, easy processing and forming and the like enable the polyurethane to be widely applied in various fields, and the polyurethane is generally used as plastics, rubber, fibers, adhesives, synthetic leather, waterproof materials and the like. The yield of polyurethane is the sixth place in the global polymer material, but most of the currently used polyurethane is not degradable under natural conditions, so that the recycling is difficult and the problem of environmental pollution is serious. Legislation has been legislated in many countries around the world to restrict the use of disposable non-degradable plastics, greatly facilitating the research and development of degradable polyurethanes. The development of degradable polyurethane can be divided into several stages of blending with natural substances, blending after modification, copolymerization with natural substances, molecular chain design and the like according to the time sequence and the technical development degree. The molecular chain design is a method for preparing degradable polyurethane by respectively carrying out degradable design on a soft segment (polyether (ester) polyol) and a hard segment (isocyanate and a chain extender) in a polyurethane molecular chain. It is well known that the controlled introduction of ester bonds, in particular aliphatic ester bonds, in the main chain of a polymer can confer to the material a degradability under specific (acidic, basic or biological) conditions. However, polyether urethanes are limited by the strong alkaline environment used in the current polyether synthesis process, and introduction of ester bonds into the polyether backbone can induce a severe transesterification reaction, so that the polyether chains grow slowly and the structural controllability is reduced. Thus, the main reliance on the achievement of degradability of polyether urethanes is the use of block copolymers of polyether-polyesters (polycaprolactone, polypentanolactone, polylactide), or isocyanates, chain extenders with ester/acetal groups. However, the synthesis of polyether-polyester block copolymers requires ring-opening polymerization of lactone monomers initiated by conventional polyether diols, or macromolecular coupling reactions of polyethers with polyesters. The synthesis of polyether-polyester block copolymer requires more solvents, consumes more energy and has low yield because of the low terminal group reactivity of macroinitiator/monomer. More seriously, the introduction of the polyester block at the end of the polyether chain can reduce the flexibility of the molecular chain, thereby causing influence on the performances of high elasticity and the like of the polyurethane. On the other hand, the special isocyanate and the chain extender with ester bonds/acetals can be obtained only by multi-step small molecule reaction, and the method is complex in process, high in price and not suitable for large-scale production. The Chinese invention patent (CN 201910004162.5) discloses a method for preparing polyether controllably by using carboxylic acid as an initiator, and provides a method for preparing esterified polyether polyol by performing controllable ring-opening polymerization on an epoxy monomer by using a carboxylic acid type catalysis/initiation system. The carboxylic acid type catalysis/initiation system takes a carboxylic acid compound as an initiator and a Lewis acid-base pair constructed by organic base and alkyl boron as a catalysis system, can effectively inhibit ester exchange reaction, and controllably introduces aliphatic ester bonds into the chain ends/chains of polyether. But it is not used for further preparation of degradable polyether urethanes.

Disclosure of Invention

Aiming at the defects and shortcomings of the prior art, the invention aims to provide a preparation method of degradable polyether polyurethane. The method of the invention utilizes the esterification polyether polyol synthesized by the carboxylic acid initiator to polymerize with isocyanate, and ester bonds are controllably introduced into the main chain of a macromolecule, thereby endowing the material with degradable performance.

The invention also aims to provide the degradable polyether polyurethane prepared by the method.

The purpose of the invention is realized by the following technical scheme:

a preparation method of degradable polyether polyurethane comprises the following preparation steps:

(1) under inert atmosphere, adding an epoxy monomer into a carboxylic acid type catalysis/initiation system for reaction to obtain esterified polyether polyol; the carboxylic acid type catalytic/initiation system comprises a carboxylic acid compound, an organic base, and an alkyl boron; the carboxylic acid compound is hydroxycarboxylic acid containing at least one carboxyl group or polycarboxylic acid containing at least two carboxyl groups;

(2) and (2) mixing the esterified polyether polyol obtained in the step (1) with isocyanate for reaction to obtain the degradable polyether polyurethane.

Further, the epoxy monomer comprises but is not limited to ethylene oxide, propylene oxide, butylene oxide, alkyl ethylene oxide with the alkyl carbon number of 3-20, epichlorohydrin, styrene oxide, butyl glycidyl ether, tert-butyl glycidyl ether, phenyl glycidyl ether, allyl glycidyl ether, propargyl glycidyl ether, glycidyl methacrylate and epoxy cyclohexane.

Further, the carboxylic acid compound is selected from at least one of the following compounds: (1) lactic acid or its homologue, (2) 1-hydroxycyclohexanecarboxylic acid, (3) salicylic acid, (4) malic acid, (5) 2-hydroxycyclohexanecarboxylic acid, (6) 3-hydroxycyclohexanecarboxylic acid, (7) 4-hydroxycyclohexanecarboxylic acid, (8) citric acid, (9) maleic acid, (10) fumaric acid, (11) oxalic acid or its homologue, (12) diglycolic acid or homologue, (13) glutaconic acid or its homologue, (14) diunsaturated dicarboxylic acid, (15) 2-methyllinear fatty diacid, (16) 3-methyllinear fatty diacid, (17)3, 3-dimethylglutaric acid, (18) 3-ethyl-3-methylglutaric acid, (19)2, 2-dimethylsuccinic acid, (20)2, 2-dimethylglutaric acid, salicylic acid, 4) oxalic acid or its homologue, (21) 2-oxoglutaric acid, (22)2, 4-diethylglutaric acid, (23)1, 1-cyclobutanedicarboxylic acid, (24)1, 1-cyclopentanediacetic acid, (25) cyclopentylmalonic acid, (26)1, 1-cyclohexanediacetic acid, (27)1, 2-cyclohexanedicarboxylic acid, (28)1, 3-cyclohexanedicarboxylic acid, (29)1, 4-cyclohexanedicarboxylic acid, (30) bicyclo [2.2.2] octane-1, 4-dicarboxylic acid, (31) norbornenedioic acid, (32) decahydro-1, 4-naphthalenedicarboxylic acid, (33) phthalic acid, (34) isophthalic acid, (35) terephthalic acid, (36) tricarballylic acid or a homologue thereof, (37)1,2, 3-propanetricarboxylic acid or a homologue thereof, (38)1,2, 4-benzenetricarboxylic acid, (39)1,3, 5-benzenetricarboxylic acid, (40) butanetetracarboxylic acid. The specific representative structural formula is as follows:

further, the organic base is selected from tertiary amines (DABCO, PMDETA, ME)₆TREN, sparteine), amidines (DBN, DBU), guanidines (MTBD, TMG, PMG), triaminophosphines (HMTP, HETP, TMAP, TIPAP) or phosphazene bases (BEMP, t-BuP)₁，t-BuP₂，EtP₂，t-BuP₄) And the like. The specific structural formula is as follows:

further, the alkyl boron is selected from B-isopinocampheyl-9-borabicyclo [3.3.1]Nonane (S-Alphine-Borane), tri-sec-butylborane (T)^sBuB), triisopropylborane (T)ⁱPrB), Trimethylborane (TMB) or tri-linear alkylborane (TAB) having an alkyl group having 2 to 8 carbon atoms. The specific structural formula is as follows:

further, the isocyanate includes, but is not limited to, m-phenylene diisocyanate, 1, 4-phenylene diisocyanate, 2, 4-toluene diisocyanate, 2, 6-toluene diisocyanate, 1, 6-hexamethylene diisocyanate, isophorone diisocyanate, tetramethylxylene diisocyanate, tetramethylene diisocyanate, 1, 4-diisocyanate cyclohexane, hexahydrotoluene diisocyanate, 1, 5-naphthalene diisocyanate, 1-methoxyphenyl-2, 4-diisocyanate, 2 '-diphenylmethane diisocyanate, 2, 4' -diphenylmethane diisocyanate, 4 '-biphenylene diisocyanate, 3' -dimethoxy-4, 4 ' -biphenylylene diisocyanate, 3 ' -dimethyldiphenylmethane-4, 4 ' -diisocyanate, 4 ' -triphenylmethane triisocyanate, 2,4, 6-triisocyanate toluene, 4 ' -dimethyldiphenylmethane-2, 2 ' -5,5 ' -tetraisocyanate, polymethylpolyphenylenepolyisocyanate.

Further, a small molecular chain extender or a curing agent is further added in the mixing reaction process in the step (2) for reaction.

Further, the chain extender includes, but is not limited to, small molecular alcohol compounds such as ethylene glycol, 1, 3-propanediol, 1, 4-butanediol, 2, 3-butanediol, 1, 5-pentanediol, 1, 6-hexanediol, 1, 4-tetramethylglycol, 1, 4-dihydroxy-1, 2,3, 4-tetrahydronaphthalene, hydroquinone diether (HQEE), glycerin, trimethylolpropane, diethylene glycol, triethylene glycol, neopentyl glycol, sorbitol, diethylaminoethanol, etc.; the curing agent includes, but is not limited to, 3' -dichloro-4, 4-diaminodiphenylmethane (MOCA), ethylenediamine (DA), N-dihydroxy (diisopropyl) aniline (HPA), diaminobenzene, diaminobiphenyl, dimethyldiaminobiphenyl, dimethoxydiaminobiphenyl, dichlorodiaminobiphenyl, and other small molecule amine compounds.

Further, at least one of auxiliary materials such as a reinforced composite material, an accelerator, a diluent, a plasticizer, a toughening agent, a thickening agent, a coupling agent, a foaming agent, a defoaming agent, a leveling agent, an ultraviolet absorbent, an antioxidant, a brightening agent, a fluorescent reagent, a pigment, a filler and the like is further added in the mixing reaction process in the step (2).

A degradable polyether polyurethane is prepared by the method.

Further, the degradable polyether polyurethane can be degraded under acidic conditions, alkaline conditions or biological conditions; the acidic condition is at least one of inorganic acids such as perchloric acid, hydroiodic acid, hydrobromic acid, hydrochloric acid, sulfuric acid, sulfurous acid, iodic acid, nitric acid, nitrous acid, acetic acid, oxalic acid, phosphoric acid and the like; the alkaline condition is potassium hydroxide (KOH), sodium hydroxide (NaOH), barium hydroxide (Ba (OH)₂) Calcium hydroxide (Ca (OH)₂) And at least one of inorganic bases such as phosphazene base, amidines (DBN, DBU), and guanidines (MTBD, TMG, and PMG); said raw material isThe condition refers to Lipase such as Lipase PS and the like or microbial degradation.

The preparation method and the obtained product have the following advantages and beneficial effects:

(1) the method utilizes the carboxylic acid initiator to synthesize the esterified polyether polyol, has the advantages of simple and easily obtained raw materials, low price and rich stock in nature, and accords with the concepts of green chemistry and sustainable development.

(2) The method utilizes the carboxylic acid initiator to synthesize the esterified polyether polyol, and has the advantages of high and controllable reaction, small solvent consumption and definite product structure.

(3) The method utilizes carboxylic acid initiator to synthesize esterified polyether polyol, and the Lewis acid-base pair catalytic system constructed by the used organic base and alkyl boron can efficiently catalyze the polymerization reaction of polyether glycol and isocyanate without purification and removal, and can selectively add or not add step-by-step polymerization catalyst or micromolecule chain extender, curing agent and the like.

(4) The method of the invention firstly proposes that esterified polyether polyol is polymerized with isocyanate, chain extender and other small molecules, and ester bonds are introduced into the main chain of polyurethane, thereby endowing the polyurethane with degradability.

(5) Compared with a polyether-polyester segmented copolymer method, the method has the advantages that the degradable soft segment is simple and convenient to synthesize, designability is strong, and molecular chain flexibility is high; on the premise of not influencing the performance of polyurethane, the material can be endowed with obvious degradability by introducing a small amount of ester bonds.

(6) Compared with the method of introducing ester bonds or acetals into isocyanate or a micromolecular chain extender, the method of the invention has the advantage that no extra micromolecular pre-synthesis step is needed.

(7) The method utilizes the esterified polyether polyol synthesized by blending polycarboxylic acid initiator to prepare degradable polyurethane, can directly introduce a cross-linked network structure, and improves the mechanical property of the material; after the crosslinking points are degraded, the crosslinking structure disappears, and the polyurethane degradation product can be recycled.

(8) The method of the invention utilizes the mixture of the esterified polyether polyol and the conventional polyether polyol (polyether blending method or alcohol blending and carboxylic acid initiator method) to prepare the degradable polyurethane, can adjust the ester bond density in the main chain of the macromolecule, and further realizes the controllable degradation rate.

Detailed Description

The present invention will be described in further detail with reference to examples, but the embodiments of the present invention are not limited thereto.

Example 1

In this example, hydroxy acid is used as an initiator to perform ring-opening polymerization of ethylene oxide to synthesize polyethylene oxide glycol (ester-bonded PEG 1, the number of ester bonds is 1, and hereinafter referred to as ePEG 1) having a single ester bond in the middle of a polymer chain.

The specific operation is as follows:

in an inert atmosphere, 1 part (molar part) of lactic acid was added to a dry glass reactor, and dried tetrahydrofuran was added to dissolve. Continuing to add t-BuP containing 0.005 part phosphazene base₁And 0.025 parts of triethylborane in tetrahydrofuran, and uniformly mixing the mixture by stirring. The glass reactor was connected to a vacuum line, and part of the gas in the bottle was vented and cooled with an ice-water bath. Adding 45 parts of dry ethylene oxide at 0-4 ℃, sealing the glass reactor and reacting for 4 hours at room temperature (20-30 ℃). After the ethylene oxide reaction was complete, it was observed that a solid product precipitated within the glass reactor. Opening the reactor under an inert atmosphere (in a glove box or during inert gas introduction), taking out a small amount of reaction products, adding the reaction products into deuterated chloroform for nuclear magnetic resonance hydrogen spectrum test (a¹H NMR) and further diluted with tetrahydrofuran for volume exclusion chromatography (SEC). Theoretical number average molecular weight M of polyethylene oxide_n,thIt was 2.0 kg/mol. The molecular weight is 2.1kg/mol by SEC, with a dispersity of 1.10.

Example 2

In this example, glutaric acid was used as an initiator to perform ring-opening polymerization of ethylene oxide to synthesize polyethylene oxide glycol (ester bond number 2, hereinafter referred to as ePEG 2) having a double ester bond in the middle of a polymer chain. In this example, the carboxylic acid initiator was replaced with 1 part (mol) of glutaric acidOtherwise, the same as in example 1. Sealing the reactor and reacting for 4h at room temperature to obtain the product. Theoretical number average molecular weight M of polyethylene oxide_n,thIt was 2.0 kg/mol. The molecular weight is 2.1kg/mol by SEC, with a dispersity of 1.12.

Example 3

In this example, hydroxy acid is used as an initiator to perform ring-opening polymerization of propylene oxide to synthesize polypropylene oxide glycol (esterified PPG 1, the number of ester bonds is 1, hereinafter referred to as ePG 1) having a single ester bond in the middle of a polymer chain.

The specific operation is as follows:

in an inert atmosphere, 1 part (molar part) of lactic acid was added to a dry glass reactor, and dried tetrahydrofuran was added to dissolve. Continuing to add t-BuP containing 0.05 part of phosphazene base₂And 0.15 part of triethylborane in tetrahydrofuran was mixed with stirring. 30 parts of dry propylene oxide were added further, the glass reactor was sealed and reacted at room temperature for 6 h. Opening the reactor under inert atmosphere (in a glove box or during inert gas introduction), taking out a small amount of reaction solution, adding the reaction solution into deuterated chloroform for nuclear magnetic resonance hydrogen spectrum test (a¹H NMR) and further diluted with tetrahydrofuran for volume exclusion chromatography (SEC).¹The conversion of propylene oxide monomer was determined by H NMR to be 100%, the theoretical number average molecular weight M of the polypropylene oxide_n,thIt was 1.9 kg/mol. The molecular weight is 2.5kg/mol, determined by SEC, and the dispersity is 1.07.

Example 4

In this example, a dicarboxylic acid was used as an initiator to perform ring-opening polymerization of propylene oxide to synthesize polypropylene oxide glycol (esterified PPG2, the number of ester bonds is 2, hereinafter referred to as ePG 2) having a double ester bond in the middle of a polymer chain. In this example, the carboxylic acid initiator was replaced with 1 part (mole part) of adipic acid, and the rest was the same as in example 3. Sealing the reactor and reacting for 7h at room temperature to obtain the product.¹The conversion of propylene oxide monomer was determined by H NMR to be 100%, the theoretical number average molecular weight M of the polypropylene oxide_n,thIt was 1.9 kg/mol. The molecular weight is 2.6kg/mol, determined by SEC, and the dispersity is 1.06.

Example 5

The true bookIn the examples, a ring-opening polymerization of propylene oxide was carried out using a tricarboxylic acid as an initiator to synthesize a branched polypropylene oxide triol (esterified PPG3, the number of ester bonds is 3, hereinafter referred to as ePG 3) having a three-ester bond in the middle of a polymer chain. In this example, the carboxylic acid initiator was replaced with 1 part (mol part) of tricarballylic acid and the epoxy monomer was replaced with 50 parts of dry propylene oxide, and the rest was the same as in example 3. Sealing the glass reactor and reacting for 8h at room temperature to obtain the product.¹The conversion of propylene oxide monomer was determined by H NMR to be 100%, the theoretical number average molecular weight M of the polypropylene oxide_n,thIt was 3.0 kg/mol. The molecular weight is 3.5kg/mol by SEC, dispersity 1.05.

Example 6

In this example, a carboxylic acid mixture was used as an initiator to perform ring-opening polymerization of propylene oxide to synthesize an esterified polypropylene oxide polyol. This example was conducted in the same manner as example 3 except that adipic acid and malonic acid were mixed in a certain molar ratio (0.5/0.5) and used as an initiator and the epoxy monomer was replaced with 40 parts of dry propylene oxide. Sealing the reactor and reacting for 6h at room temperature to obtain the product. The product obtained is esterified polypropylene oxide diol (theoretical number average molecular weight M)_n,th2.0kg/mol) and esterified polypropylene oxide triol (theoretical number average molecular weight M)_n,th3.0kg/mol) in a molar ratio of 0.5/0.5 (hereinafter referred to as ePG 2+ 3).

Example 7

In this example, a mixture of dicarboxylic acid and small molecule diol is used as an initiator to perform ring-opening polymerization of propylene oxide, so as to synthesize partially esterified polypropylene oxide polyol. This example uses adipic acid and 1, 4-butanediol mixed in a certain molar ratio (0.5/0.5) as initiators, the other being the same as in example 3. Sealing the reactor and reacting for 5h at room temperature to obtain the product. The product obtained is esterified polypropylene oxide diol (theoretical number average molecular weight M)_n,th2.0kg/mol) and a conventional polypropylene oxide diol in a molar ratio of 0.5/0.5 (hereinafter ePPG m).

Example 8

In this example, glutaconic acid is used as initiator to carry out ring-opening polymerization of butylene oxide to synthesize polybutylene oxide with diester bond in the middle of polymer chainAlkylene glycol (esterified PBG 2, ester bond number 2, hereinafter ePBG 2). This example was conducted in the same manner as example 3 except that the carboxylic acid initiator was changed to 1 part (mole part) of glutaconic acid and the epoxy monomer was changed to 25 parts of dry butylene oxide. Sealing the glass reactor and reacting for 12h at room temperature to obtain the product.¹The conversion of butylene oxide monomer was determined by H NMR to be 100%, the theoretical number average molecular weight M of the polybutylene oxide_n,thIt was 2.0 kg/mol. The molecular weight is 2.3kg/mol, determined by SEC, and the dispersity is 1.06.

Example 9

In this example, a mono-esterified polyethylene oxide ePEG 1 is used as a macrodiol to react with an equimolar amount of isocyanate to prepare a degradable polyethylene oxide polyurethane. The specific operation is as follows:

mixing the crude product of ePEG 1, a tetrahydrofuran solvent and diphenylmethane diisocyanate (MDI) according to a mass ratio of 100/20/13, sealing the reactor, reacting at room temperature for 3 hours, and precipitating and separating out polyurethane in tetrahydrofuran. And opening the reactor, collecting the product and drying in vacuum to obtain the catalyst. The molecular weight of the polyurethane, determined by SEC, was 53.2kg/mol, with a dispersity of 2.05.

Example 10

In the embodiment, the double-esterified polyethylene oxide ePEG 2 is used as macromolecular dihydric alcohol to react with isocyanate with the same molar component to prepare degradable polyethylene oxide polyurethane. The polyethylene oxide was replaced with ePEG 2, and the procedure was otherwise the same as in example 9. Sealing the reactor and reacting for 3h at room temperature to obtain the product. The polyurethane has a molecular weight of 59.6kg/mol, determined by SEC, and a dispersity of 2.02.

Example 11

In this example, a mono-esterified polypropylene oxide ePG 1 is used as a macromolecular diol to react with an isocyanate with an equal molar component to prepare a degradable polypropylene oxide type polyurethane. Mixing the crude product of the ePG 1 and Hexamethylene Diisocyanate (HDI) according to a mass ratio of 100/9, sealing the reactor and reacting for 1h at room temperature to obtain the product. The molecular weight of the polyurethane, determined by SEC, was 5.3kg/mol, with a dispersity of 2.05.

Example 12

In this example, the double esterified polypropylene oxide ePPG 2 is used as a macromolecular diol to react with isocyanate of an equimolar component to prepare degradable polypropylene oxide based polyurethane. Mixing the crude product of ePG 2 and Toluene Diisocyanate (TDI) according to the mass ratio of 100/9, sealing the reactor and reacting for 0.5h at room temperature to obtain the product. The polyurethane has a molecular weight of 8.5kg/mol, determined by SEC, and a dispersity of 1.93.

Example 13

This example prepared degradable polyethylene oxide urethanes by reacting polypropylene oxide diols of different degrees of esterification with equimolar amounts of the isocyanate component. Mixing the crude product of ePG 1, the crude product of ePG 2 and Toluene Diisocyanate (TDI) according to the mass ratio of 100/100/18, sealing the reactor and reacting for 0.5h at room temperature to obtain the product. The polyurethane has a molecular weight of 7.4kg/mol, determined by SEC, and a dispersity of 2.03.

Example 14

In the embodiment, the degradable soft polyurethane is prepared by using the reaction of the diester polypropylene oxide ePG 2 and isocyanate as a soft segment and the micromolecular diol as a chain extender. The crude product of ePPG 2 and MDI were mixed in a mass ratio of 100/25, the reactor was sealed and reacted at room temperature for 0.5 h. Continuously adding 5 parts (mass fraction) of 1, 4-butanediol, sealing the reactor and reacting for 0.5h at room temperature to obtain the product.

Example 15

In the embodiment, the degradable rigid polyurethane is prepared by using the reaction of the diester polypropylene oxide ePG 2 and isocyanate as a soft segment and the micromolecule diamine as a curing agent. The crude product of ePPG 2 and MDI were mixed in a mass ratio of 100/25, the reactor was sealed and reacted at room temperature for 0.5 h. And continuously adding 14 parts by mass of 3, 3' -dichloro-4, 4-diaminodiphenylmethane (MOCA), vigorously stirring in vacuum for quick defoaming, and curing the mixture at room temperature to obtain the product.

Example 16

In the embodiment, the cross-linked degradable polyurethane is prepared by using the reaction of the bi-esterified polypropylene oxide ePG 2 and isocyanate as a soft segment, the micromolecular triol as a chain extender and the micromolecular diamine as a curing agent. The crude product of ePPG 2 and MDI were mixed in a mass ratio of 100/25, the reactor was sealed and reacted at room temperature for 0.5 h. Mixing glycerol (glycerol, VG) and MOCA according to a mass ratio of 2/5, adding the mixture into the polyurethane prepolymer, then violently stirring the mixture in vacuum for quick defoaming, and crosslinking and curing the mixture at room temperature to obtain the polyurethane prepolymer.

Example 17

In the embodiment, the degradable polyurethane soft foam is prepared by reacting the bi-esterified polypropylene oxide ePG 2 with isocyanate to serve as a soft segment, taking micromolecule triol as a chain extender and taking micromolecule diamine as a curing agent. Mixing the crude product of ePG 2, Toluene Diisocyanate (TDI), VG and ethylenediamine (DA) according to the mass ratio of 100/18/2/1.2, adding a foaming agent with the total volume fraction of 2%, mixing under high-speed stirring, and pouring into a mold for foaming to obtain the product.

Example 18

In the embodiment, the degradable polyurethane rigid foam is prepared by reacting the bi-esterified polypropylene oxide ePG 2 with isocyanate to serve as a soft segment, using micromolecular triol as a chain extender and using micromolecular diamine as a curing agent. Mixing the crude product of ePG 2, MDI, VG and MOCA according to the mass ratio of 100/25/2/5, adding a foaming agent accounting for 2 percent of the total volume, mixing under high-speed stirring, and pouring into a mold for foaming to obtain the product.

Example 19

In the embodiment, tri-esterified polypropylene oxide ePG 3 is used as macromolecular triol to react with isocyanate with equal molar components to prepare the crosslinking type degradable soft polyurethane. Mixing the crude product of ePG 3 and HDI according to the mass ratio of 100/9, sealing the reactor and reacting for 2h at room temperature to obtain the product.

Example 20

In the embodiment, the cross-linked degradable polyurethane flexible foam is prepared by using tri-esterified polypropylene oxide ePG 3 and isocyanate to react as a soft segment and using micromolecular diamine as a curing agent. Mixing the crude product of ePG 3, TDI and DA according to the mass ratio of 100/18/3, adding a foaming agent with the total volume fraction of 2%, mixing under high-speed stirring, and pouring into a mold for foaming to obtain the product.

Example 21

In the embodiment, the cross-linked degradable polyurethane rigid foam is prepared by using tri-esterified polypropylene oxide ePG 3 and isocyanate to react to form a soft segment, using micromolecular triol as a chain extender and using micromolecular diamine as a curing agent. Mixing the crude product of ePG 3, MDI, VG and MOCA according to the mass ratio of 100/18/2/5, adding a foaming agent accounting for 2 percent of the total volume fraction, mixing under high-speed stirring, and pouring into a mold for foaming to obtain the product.

Example 22

This example utilizes blended polypropylene oxide polyols of different degrees of esterification reacted with equimolar amounts of isocyanate to produce a semi-crosslinked degradable polyurethane. Mixing the crude product of ePG 2, the crude product of ePG 3 and MDI according to the mass ratio of 100/100/25, then violently stirring and quickly defoaming in vacuum, and crosslinking the mixture at room temperature to obtain the product.

Example 23

In this example, the cross-linked degradable polyurethane is prepared by reacting blended polypropylene oxide polyols with different esterification degrees with isocyanate and a curing agent. Mixing the crude product of ePG 2, the crude product of ePG 3, MDI and MACO according to the mass ratio of 100/100/35/10, then violently stirring in vacuum for quick defoaming, and crosslinking and curing the mixture at room temperature to obtain the product.

Example 24

This example utilizes a one-step process to prepare semi-crosslinked degradable polyurethanes by reacting mixtures of polypropylene oxide polyols of different degrees of esterification with equimolar amounts of isocyanate. And (2) mixing the crude product of ePG 2+3 obtained in the example 6 and MDI according to the mass ratio of 100/12.5, then violently stirring under vacuum for quick defoaming, and crosslinking and curing the mixture at room temperature to obtain the product.

Example 25

In this example, the blended esterified polypropylene oxide diol is reacted with conventional polypropylene oxide, isocyanate and curing agent to prepare degradable polyurethane. And (2) mixing the crude product of ePG 2 obtained in the example 4, conventional PPG2000, MDI and MACO according to the mass ratio of 100/100/35/10, then violently stirring in vacuum for quick defoaming, and crosslinking and curing the mixture at room temperature to obtain the product. This example illustrates that the ester bond density of degradable polyurethanes can be adjusted by blending the ratio of esterified polyether to conventional polyether to achieve a controlled degradation rate.

Example 26

In this example, the degradable polyurethane is prepared by reacting the mixture of esterified polypropylene oxide diol prepared by the one-step method and conventional polypropylene oxide with isocyanate and a curing agent. And (3) mixing the crude product of ePPG m obtained in the example 7, MDI and MACO according to the mass ratio of 100/25/14, then violently stirring in vacuum for quick defoaming, and crosslinking and curing the mixture at room temperature to obtain the product. This example illustrates that the ester bond density of degradable polyurethanes can be adjusted by the acid/alcohol blend ratio used to perform the ring opening polymerization of the epoxy monomers, thereby achieving a controlled degradation rate.

Example 27

In the embodiment, the degradable soft polyurethane is prepared by using the reaction of diester polybutylene oxide ePDG 2 and isocyanate as a soft segment and using micromolecular diol as a chain extender. The crude product of ePDG 2 and MDI were mixed in a mass ratio of 100/25, the reactor was sealed and the reaction was carried out at room temperature for 0.5 h. Continuously adding 5 parts (mass fraction) of 1, 4-butanediol, sealing the reactor and reacting for 0.5h at room temperature to obtain the product.

Example 28

This example is the degradation of a degradable polyurethane under alkaline conditions. The specific operation is as follows: 95 g of tetrahydrofuran and 5 g of sodium hydroxide are added into a 250mL flask, stirring is started, 1g of polyurethane (with the thickness of 2mm and the width of 2-3mm) obtained in example 15 is put into the solution, the temperature is raised by heating in an oil bath, the internal temperature is controlled to be 60-80 ℃, timing is started until the degradation is complete (the solid is completely dissolved in the solution to obtain a light yellow solution), and the recording time is 1 hour.

Example 29

This example is the degradation of a cross-linked degradable polyurethane under acidic conditions. The specific operation is as follows: 95 g of tetrahydrofuran solution and 5 g of concentrated hydrochloric acid are added into a 250mL flask, stirring is started, 0.3 g of polyurethane rigid foam (the thickness is 2mm, the width is 2-3mm) obtained in example 21 is put into the solution, the temperature is raised by heating in an oil bath, the temperature is controlled to be 45-80 ℃, time is started until the degradation is complete (the solid is completely dissolved in the solution to obtain a colorless solution), and the recording time is 3 hours. Heating is continued for 8 hours, and the polyether chain ends are completely degraded into small molecules under the acidic condition.

Example 30

This example illustrates the enzymatic degradation of degradable polyurethanes. The specific operation is as follows: lipase PS Lipase was dissolved in PBS buffer (0.14M, pH 7.4) to prepare a solution having a concentration of 1 g/L. 1g of the polyurethane obtained in example 26 (thickness 2mm, width 2-3mm) was added to the solution and stirred at room temperature, and a timer was started until the degradation was complete (complete dissolution of the solid in the solution to give a colorless solution) and the time was recorded for 15 minutes.

The above embodiments are preferred embodiments of the present invention, but the present invention is not limited to the above embodiments, and any other changes, modifications, substitutions, combinations, and simplifications which do not depart from the spirit and principle of the present invention should be construed as equivalents thereof, and all such changes, modifications, substitutions, combinations, and simplifications are intended to be included in the scope of the present invention.

Claims

1. The preparation method of the degradable polyether polyurethane is characterized by comprising the following preparation steps:

2. The method for preparing a degradable polyether urethane according to claim 1, wherein the method comprises the following steps: the epoxy monomer is at least one of ethylene oxide, propylene oxide, butylene oxide, alkyl ethylene oxide with alkyl carbon number of 3-20, epichlorohydrin, styrene oxide, butyl glycidyl ether, tert-butyl glycidyl ether, phenyl glycidyl ether, allyl glycidyl ether, propargyl glycidyl ether, methacrylic acid glycidyl ether and epoxy cyclohexane.

3. The method of claim 1, wherein the carboxylic acid compound is at least one compound selected from the group consisting of: (1) lactic acid or its homologue, (2) 1-hydroxycyclohexanecarboxylic acid, (3) salicylic acid, (4) malic acid, (5) 2-hydroxycyclohexanecarboxylic acid, (6) 3-hydroxycyclohexanecarboxylic acid, (7) 4-hydroxycyclohexanecarboxylic acid, (8) citric acid, (9) maleic acid, (10) fumaric acid, (11) oxalic acid or its homologue, (12) diglycolic acid or homologue, (13) glutaconic acid or its homologue, (14) diunsaturated dicarboxylic acid, (15) 2-methyllinear fatty diacid, (16) 3-methyllinear fatty diacid, (17)3, 3-dimethylglutaric acid, (18) 3-ethyl-3-methylglutaric acid, (19)2, 2-dimethylsuccinic acid, (20)2, 2-dimethylglutaric acid, salicylic acid, 4) oxalic acid or its homologue, (21) 2-oxoglutaric acid, (22)2, 4-diethylglutaric acid, (23)1, 1-cyclobutanedicarboxylic acid, (24)1, 1-cyclopentanediacetic acid, (25) cyclopentylmalonic acid, (26)1, 1-cyclohexanediacetic acid, (27)1, 2-cyclohexanedicarboxylic acid, (28)1, 3-cyclohexanedicarboxylic acid, (29)1, 4-cyclohexanedicarboxylic acid, (30) bicyclo [2.2.2] octane-1, 4-dicarboxylic acid, (31) norbornenedioic acid, (32) decahydro-1, 4-naphthalenedicarboxylic acid, (33) phthalic acid, (34) isophthalic acid, (35) terephthalic acid, (36) tricarballylic acid or a homologue thereof, (37)1,2, 3-propanetricarboxylic acid or a homologue thereof, (38)1,2, 4-benzenetricarboxylic acid, (39)1,3, 5-benzenetricarboxylic acid, (40) butanetetracarboxylic acid.

4. The method for preparing a degradable polyether urethane according to claim 1, wherein the method comprises the following steps: the organic base is selected from tertiary amine, amidine, guanidine, triamino phosphine or phosphazene base; the alkyl boron is selected from B-isopinocampheyl-9-boron bicyclo [3.3.1] nonane, tri-sec-butylborane, triisopropylborane, trimethylborane or tri-linear alkyl borane with alkyl carbon atom number of 2-8.

5. The method for preparing a degradable polyether urethane according to claim 1, wherein the method comprises the following steps: the isocyanate is selected from m-phenylene diisocyanate, 1, 4-phenylene diisocyanate, 2, 4-toluene diisocyanate, 2, 6-toluene diisocyanate, 1, 6-hexamethylene diisocyanate, isophorone diisocyanate, tetramethyl xylene diisocyanate, tetramethylene diisocyanate, 1, 4-diisocyanate cyclohexane, hexahydrotoluene diisocyanate, 1, 5-naphthalene diisocyanate, 1-methoxyphenyl-2, 4-diisocyanate, 2 ' -diphenylmethane diisocyanate, 2,4 ' -diphenylmethane diisocyanate, 4 ' -biphenylene diisocyanate, 3 ' -dimethoxy-4, 4 ' -biphenylene diisocyanate, 3,3 '-dimethyldiphenylmethane-4, 4' -diisocyanate, 4 '-triphenylmethane triisocyanate, 2,4, 6-triisocyanate toluene, 4' -dimethyldiphenylmethane-2, 2 '-5, 5' -tetraisocyanate, polymethylpolyphenylpolyisocyanate.

6. The method for preparing a degradable polyether urethane according to claim 1, wherein the method comprises the following steps: and (3) at least one of a micromolecule chain extender and a curing agent is further added in the mixing reaction process in the step (2) for reaction.

7. The method of claim 6, wherein the method comprises the following steps: the chain extender is at least one of ethylene glycol, 1, 3-propylene glycol, 1, 4-butanediol, 2, 3-butanediol, 1, 5-pentanediol, 1, 6-hexanediol, 1, 4-tetramethylglycol, 1, 4-dihydroxy-1, 2,3, 4-tetrahydronaphthalene, hydroquinone diether, glycerol, trimethylolpropane, diethylene glycol, triethylene glycol, neopentyl glycol, sorbitol and diethylaminoethanol; the curing agent is at least one of 3, 3' -dichloro-4, 4-diaminodiphenylmethane, ethylenediamine, N-dihydroxy (diisopropyl) aniline, diaminobenzene, diaminobiphenyl, dimethyldiaminobiphenyl, dimethoxydiaminobiphenyl and dichlorodiaminobiphenyl.

8. The method for preparing a degradable polyether urethane according to claim 1, wherein the method comprises the following steps: and (3) in the mixing reaction process in the step (2), at least one of a reinforced composite material, an accelerator, a diluent, a plasticizer, a flexibilizer, a thickening agent, a coupling agent, a foaming agent, a defoaming agent, a leveling agent, an ultraviolet absorbent, an antioxidant, a brightening agent, a fluorescent reagent, a pigment and a filler is further added.

9. A degradable polyether polyurethane is characterized in that: prepared by the method of any one of claims 1 to 8.

10. The degradable polyether urethane of claim 9 wherein: the degradable polyether polyurethane can be degraded under acidic condition, alkaline condition or biological condition; the acidic condition is at least one of perchloric acid, hydroiodic acid, hydrobromic acid, hydrochloric acid, sulfuric acid, sulfurous acid, iodic acid, nitric acid, nitrous acid, acetic acid, oxalic acid and phosphoric acid; the alkaline condition is at least one inorganic base condition of potassium hydroxide, sodium hydroxide, barium hydroxide and calcium hydroxide or at least one organic base condition of phosphazene base, amidine and guanidine; the biological condition refers to one of lipase or microbial degradation.