阅读说明：本技术 一种用于聚氨酯形状记忆材料的不饱和木质纤维素材料的制备方法 (Preparation method of unsaturated lignocellulose material for polyurethane shape memory material ) 是由 蔡兰花 王芳 李培则 于 2020-08-17 设计创作，主要内容包括：本发明公开一种用于聚氨酯形状记忆材料的不饱和木质纤维素材料的制备方法,按照质量份数,将30-50份的木质纤维素,59-80份肉桂酸,5-12份的D001树脂催化剂和200-320份的水,0.03-0.2份1-羧乙基-3-甲基咪唑硝酸盐,混合均匀,控温70-80℃,搅拌3-7h,蒸发,烘干后研磨成50-70目的粉末,得到不饱和木质纤维素材料。(The invention discloses a preparation method of an unsaturated lignocellulose material for a polyurethane shape memory material, which comprises the following steps of mixing 30-50 parts of lignocellulose, 59-80 parts of cinnamic acid, 5-12 parts of a D001 resin catalyst, 200-320 parts of water, 0.03-0.2 part of 1-carboxyethyl-3-methylimidazole nitrate in parts by mass, controlling the temperature to be 70-80 ℃, stirring for 3-7 hours, evaporating, drying and grinding into powder of 50-70 meshes to obtain the unsaturated lignocellulose material.)

1. A preparation method of unsaturated lignocellulose material for polyurethane shape memory material is characterized by comprising the following steps:

according to the mass parts, 30-50 parts of lignocellulose, 59-80 parts of cinnamic acid, 5-12 parts of D001 resin catalyst, 320 parts of water 200 and 0.03-0.2 part of 1-carboxyethyl-3-methylimidazole nitrate are uniformly mixed, the temperature is controlled at 70-80 ℃, the mixture is stirred for 3-7h, and the mixture is evaporated, dried and ground into powder of 50-70 meshes, so that the unsaturated lignocellulose material is obtained.

2. The method for preparing unsaturated lignocellulose material for polyurethane shape memory material as claimed in claim 1, wherein the unsaturated lignocellulose material is prepared by esterification reaction of lignocellulose and 1-carboxyethyl-3-methylimidazole nitrate with cinnamic acid.

3. The method for preparing unsaturated lignocellulose material for polyurethane shape memory material as recited in claim, further comprising esterification reaction of lignocellulose material with cinnamic acid, 1-carboxyethyl-3-methylimidazole nitrate, and photo-crosslinking reaction with polyurethane material containing photosensitive unit.

4. The method of claim 1, wherein the polyurethane material has photosensitive units incorporated into the polymer matrix.

5. The method of claim 4, wherein the photosensitive unit of the polyurethane material is introduced by a photochemical assistant.

6. The method as claimed in claim 5, wherein the photochemical auxiliary agent is one or more selected from cinnamic acid, methyl cinnamate, ethyl cinnamate, propyl cinnamate, and butyl cinnamate.

7. The method for preparing unsaturated lignocellulose material for polyurethane shape memory material as recited in claim 1, wherein the unsaturated lignocellulose material is modified by cinnamic acid, and photosensitive unit is introduced.

8. The method for preparing the unsaturated lignocellulose material for the polyurethane shape memory material as recited in claim 1, wherein the lignocellulose material is esterified with cinnamic acid, 1-carboxyethyl-3-methylimidazole nitrate, and then photo-crosslinked with a polyurethane material containing a photosensitive unit.

Technical Field

A preparation method of unsaturated lignocellulose material for polyurethane shape memory material.

Background

Shape Memory Polymers (SMP) are a new class of functional polymer materials which are given a certain shape (initial state) under certain conditions, and when the external conditions change, they can change the shape accordingly and fix it (morphism), and if the external environment changes again in a specific way and law, they can be reversibly restored to the initial state, so far, the cycle of "memory initial state-fixed morphism-recovery initial state" is completed. The shape memory polymer as an intelligent material plays an important role in biological materials, has wide application in surgical sutures, stents, heart valves, tissue engineering, drug release, orthopedics, optical treatment and the like, and has wide potential application value in the field of biological materials.

The traditional polyurethane shape memory material is generally a thermotropic shape memory material, and the material can be restored to the original shape only by heating the material to a temperature higher than the glass transition temperature, so that the application of the shape memory polyurethane material in the biological field is greatly limited.

CN201510064729.X discloses a thermotropic crosslinking type shape memory polyurethane material, which is obtained by thermal crosslinking of thermoplastic polyurethane with side chain double bonds, bifunctional crosslinking agent and initiator, wherein the shape fixation rate is not less than 95% in a bending mode, the shape recovery rate is not less than 90%, the shape fixation rate is not less than 95% in a dynamic mechanical analysis stretching mode, and the shape recovery rate is not less than 90%. The preparation method disclosed by the invention is a two-step method, namely, firstly preparing the thermoplastic polyurethane with side chain double bonds, and then carrying out thermal crosslinking on the thermoplastic polyurethane and the bifunctional crosslinking agent under the condition of adding an initiator through melt mixing or solution mixing. The polyurethane material disclosed by the invention has excellent shape memory performance and mechanical property, the transformation temperature is close to body temperature, the raw materials have good biocompatibility and are nontoxic and degradable, the polyurethane material can be used as an in-vivo implanted material and a clinical surgical material, can also be used for wire and cable sleeves and building pipe connecting sleeves, can also be used for a buffer sole protection device, a deformation toy and the like, and is suitable for large-scale industrial production.

CN201110131871.3 discloses a shape memory polyurethane of cross-linked type. When preparing the cross-linking type Shape Memory Polyurethane (SMPU) with good shape memory property, firstly introducing a silane coupling agent containing three siloxy groups into the end group of an isocyanate group-terminated polyurethane prepolymer, reacting to prepare a siloxy group-terminated polyurethane prepolymer, then adding or not adding a catalyst into the siloxy group-terminated polyurethane prepolymer, and cross-linking through the siloxy group to prepare the SMPU with good shape memory property; by controlling the dosage of the catalyst, SMPU with a compact structure or a porous structure with nano pores and micro pores can be prepared respectively. The shape fixing rate (Rf) of the SMPU is more than or equal to 90 percent; the shape recovery rate (Rr) is more than or equal to 90 percent. The SMPU having a porous structure of nano-pores and micro-pores has a faster recovery response speed.

CN201410586300.2 discloses a shape memory polyurethane material with high temperature recovery capability. The method is characterized in that a polyurethane shape memory material with high-temperature recovery capability is synthesized in situ by adding irradiation activated carbon wood fibers as a reinforcement, and the synthesis steps comprise: (1) activation treatment of carbon wood fiber: activating the carbon wood fiber to be activated under the irradiation of radioactive Co rays at room temperature; (2) synthesizing and purifying poly adipic acid hexanediol ester; (3) in-situ synthesis of shape memory polyurethane: firstly, synthesizing polyurethane prepolymer, then adding activated carbon wood fiber into the prepolymer for continuous reaction, and then adding chain extender for further polymerization to form polyurethane with a shape memory function. The invention can overcome the use limitation caused by lower glass transition temperature of the common shape memory polyurethane material, solves the problem of poorer mechanical property to a great extent, improves the tensile strength of the shape memory polyurethane material and expands the application field of the material.

The prior invention aims at the research of thermotropic polyurethane shape memory materials, although the thermotropic shape memory polyurethane has high shape recovery rate, simple operation and easy realization, in the field of some materials which are sensitive to heat, such as biological materials, the structure of the original material can be damaged by thermal stimulation, so that the application of the shape memory material is limited, and the photoinduced shape memory polyurethane can avoid the damage to the original material, thereby greatly expanding the application range of the shape memory material and having great significance.

Disclosure of Invention

The invention provides a preparation method of an unsaturated lignocellulose material for a polyurethane shape memory material, which is applied to the polyurethane shape memory material, and the obtained polyurethane shape memory material has shape memory capacity to light and heat.

The unsaturated lignocellulose material is prepared by reacting lignocellulose with cinnamic acid;

the unsaturated lignocellulose material is prepared by reacting lignocellulose with 1-carboxyethyl-3-methylimidazole nitrate;

the unsaturated lignocellulose material is prepared by carrying out esterification reaction on lignocellulose, 1-carboxyethyl-3-methylimidazole nitrate and cinnamic acid;

the unsaturated lignocellulose material is used for preparing a polyurethane material with a recoverable shape;

the unsaturated lignocellulose material is prepared by the following method:

according to the mass parts, 30-50 parts of lignocellulose, 59-80 parts of cinnamic acid, 5-12 parts of D001 resin catalyst, 320 parts of water 200 and 0.03-0.2 part of 1-carboxyethyl-3-methylimidazole nitrate are uniformly mixed, the temperature is controlled at 70-80 ℃, the mixture is stirred for 3-7h, and the mixture is evaporated, dried and ground into powder of 50-70 meshes, so that the unsaturated lignocellulose material is obtained.

Furthermore, the invention also discloses a preparation method of the shape recoverable polyurethane material.

Adding 60-80 parts of polyhydric alcohol into a reaction kettle, stirring at 400r/min and heating to 130-^oC, vacuumizing to-0.08 to-0.1 MPa, keeping for 2 to 4 hours, and then cooling to 45 to 60 DEG C^oC, introducing high-purity nitrogen to the standard atmospheric pressure, adding 30-40 parts of isocyanate and 1-5 parts of photochemical auxiliary agent, and heating to 80-90 DEG^oC, reacting for 2-4h, vacuumizing to-0.08 to-0.1 MPa, keeping for 2-4h, and introducing nitrogen to standard atmospheric pressure to obtain a prepolymer reaction liquid; uniformly mixing 10-20 parts of 1, 4-butanediol, 1-5 parts of diamine, 7-12 parts of unsaturated lignocellulose material and 0.1-0.5 part of catalyst, quickly adding the mixture into prepolymer reaction liquid under the protection of nitrogen, stirring at 200r/min for 1-5min, pouring the mixture into a Teflon mould, pressurizing and curing for 30-60min when the reaction liquid becomes gel, demoulding, and then placing the obtained product in a container with the content of 100-120-^oAnd C, post-curing for 15-30h to obtain the shape-recoverable polyurethane material.

Preferably, the polyalcohol is one or a combination of more of polytetrahydrofuran, poly 4-methyl butyrolactone dihydric alcohol, polypropylene glycol, polycaprolactone glycol and polycarbonate dihydric alcohol;

preferably, the weight average molecular weight of the polyol is 1000-;

preferably, the hydroxyl value of the polyol is 40-80 mgKOH/g;

preferably, the isocyanate is one or a combination of hexamethylene diisocyanate, isophorone diisocyanate, biuret triisocyanate, 2, 4-methyl diisocyanate, 1, 5-naphthalene diisocyanate and diphenylmethane diisocyanate;

preferably, the diamine is one or a combination of more of isophorone diamine, bis (4-amino-3-methylphenyl) methane, diaminodiethyltoluene and bis (4-amino-3-chlorophenyl) methane;

preferably, the catalyst is one or a combination of more of bis (ethylhexoxy) tin, dibutylene dilaurate, dimethyltin dichloride, bis (dodecylthio) dibutyltin, stannous oxalate, stannous sulfate, stannous octoate and 2, 4-bis (dimethylaminoethyl) phenol;

preferably, the photochemical auxiliary agent is one or a combination of more of cinnamic acid, methyl cinnamate, ethyl cinnamate, propyl cinnamate and butyl cinnamate, and a photosensitive unit in or in the shape-recoverable polyurethane material is introduced.

Cinnamic acid introduces light sensitive units of unsaturated lignocellulosic material.

One of the products, the photochemical auxiliary agent is self-crosslinking, and the reaction mechanism of the shape recoverable polyurethane material is shown as follows:

in another scheme, the reaction mechanism of one of the shape recoverable polyurethane materials further comprises an esterification reaction of a lignocellulose material and cinnamic acid, 1-carboxyethyl-3-methylimidazole nitrate, and then a photocrosslinking reaction of the lignocellulose material and a polyurethane material containing a photosensitive unit:

wherein the crosslinking reaction of the photocrosslinking part of the polyurethane material is shown as follows: and R represents the ionic liquid structure of 1-carboxyethyl-3-methylimidazole nitrate.

Compared with the prior art, the invention has the beneficial effects that:

1. through the chain extension reaction of polyurethane, a photosensitive unit is introduced into a polymer matrix, the photosensitive unit is crosslinked under the irradiation of ultraviolet light under a certain condition and is decrosslinked under the irradiation of ultraviolet light under another condition, so that the photoinduced reversible effect is achieved;

2. through the reasonable design of the content ratio of the soft monomer and the hard monomer, the soft structure and the hard structure of the main chain of the obtained polyurethane are subjected to microphase separation, the hard phase plays a role in thermotropic shape memory, and the soft phase plays a role in thermotropic deformation, so that the thermotropic shape recoverable polyurethane material with good shape recovery rate is obtained.

3. The unsaturated lignocellulose material is modified by cinnamic acid, a photosensitive unit is introduced, the unsaturated lignocellulose material can participate in the crosslinking reaction of the shape recoverable polyurethane material, the addition of 1-carboxyethyl-3-methylimidazole nitrate can realize the synergistic effect, the shape recoverable amplitude and the folding resistance are jointly improved, and the thermal length recovery rate and the photoinduced length recovery rate are further improved.

Drawings

FIG. 1 is a Fourier Infrared Spectroscopy of the product obtained in example 9:

at 2935cm^-1The absorption peak of hydrocarbon exists nearby and is at 1728cm^-1An absorption peak of an ester carbonyl group is present in the vicinity of 1175cm^-1An absorption peak of ester carbon oxygen exists nearby, which indicates that polycaprolactone diol participates in the reaction; at 1599cm^-1The absorption peak of the nitrogen hydrogen bond of the amide exists nearby and is 1315cm^-1Absorption peak of carbon-nitrogen single bond in amideIndicating that hexamethylene diisocyanate takes part in the reaction; at 3394cm^-1An absorption peak of hydroxyl exists nearby, which indicates that 1, 4-butanediol participates in the reaction; at 1460/1372cm^-1An absorption peak of a benzene ring exists nearby, which indicates that the cinnamic acid participates in the reaction.

Detailed Description

The raw materials used in the following examples are all commercially available products, and the examples are further illustrative of the present invention and do not limit the scope of the present invention;

the performance test methods are as follows:

1. the test method of the photoinduced shape memory recovery rate comprises the following steps: irradiating a 100 x 2 x 5mm sample strip under ultraviolet light with the wavelength of 250nm for 30s, then stretching the sample strip to 150mm, then irradiating the sample strip under ultraviolet light with the wavelength of 300nm for 30s, fixing the shape, then irradiating the sample strip under ultraviolet light with the wavelength of 250nm, and testing the light-induced length recovery rate;

2. the method for testing the recovery rate of the thermotropic shape memory comprises the following steps: a 100 x 2 x 5mm sample is placed at 120^oHeating for 10min, stretching to 150mm, rapidly cooling to room temperature, fixing shape, and heating to 120 deg.C^oC, keeping for 30s, rapidly cooling, and testing the thermally induced length recovery rate;