Preparation method of polyvinyl alcohol-based composite material and product thereof
阅读说明：本技术 一种聚乙烯醇基复合材料的制备方法及其产品 (Preparation method of polyvinyl alcohol-based composite material and product thereof ) 是由 韩建军 杨永彬 谢云涛 于 2021-08-04 设计创作，主要内容包括：本发明公开了一种聚乙烯醇基复合材料的制备方法及其产品,包括,制备聚乙烯醇水溶液；制备聚苯硫醚低聚物混合液；将聚乙烯醇水溶液和聚苯硫醚低聚物混合液混合搅拌均匀,再加入戊二醛,搅拌均匀后,室温静置,得到所述聚乙烯醇基复合材料；其中,聚乙烯醇与聚苯硫醚的质量比为5～20:1,戊二醛与聚苯硫醚的质量比为0.8～1:1。聚苯硫醚低聚物中硫醚键可以与聚乙烯醇的羟基形成氢键,使得材料中的交联点增多,PVA-PPS形状记忆复合材料形状固定率、回复率、回复速率均提高,复合材料的形状记忆性能明显优于聚乙烯醇缩戊醛材料。(The invention discloses a preparation method of polyvinyl alcohol-based composite material and a product thereof, comprising the steps of preparing polyvinyl alcohol aqueous solution; preparing polyphenylene sulfide oligomer mixed liquor; uniformly mixing and stirring a polyvinyl alcohol aqueous solution and a polyphenylene sulfide oligomer mixed solution, adding glutaraldehyde, uniformly stirring, and standing at room temperature to obtain the polyvinyl alcohol-based composite material; wherein the mass ratio of the polyvinyl alcohol to the polyphenylene sulfide is 5-20: 1, and the mass ratio of the glutaraldehyde to the polyphenylene sulfide is 0.8-1: 1. The thioether bond in the polyphenylene sulfide oligomer can form a hydrogen bond with the hydroxyl of polyvinyl alcohol, so that the number of cross-linking points in the material is increased, the shape fixing rate, the recovery rate and the recovery rate of the PVA-PPS shape memory composite material are all improved, and the shape memory performance of the composite material is obviously superior to that of a polyvinyl valeraldehyde material.)
1. A preparation method of a polyvinyl alcohol-based composite material is characterized by comprising the following steps: comprises the steps of (a) preparing a mixture of a plurality of raw materials,
preparing a polyvinyl alcohol aqueous solution;
preparing polyphenylene sulfide oligomer mixed liquor;
mixing and stirring a polyvinyl alcohol aqueous solution and a polyphenylene sulfide oligomer mixed solution, adding glutaraldehyde, uniformly stirring, and standing at room temperature to obtain the polyvinyl alcohol-based composite material; wherein the content of the first and second substances,
the mass ratio of the polyvinyl alcohol to the polyphenylene sulfide oligomer is 5-20: 1, and the mass ratio of the glutaraldehyde to the polyphenylene sulfide oligomer is 0.8-1: 1.
2. A process for the preparation of a polyvinyl alcohol-based composite material according to claim 1, characterized in that: the preparation of the polyvinyl alcohol aqueous solution comprises the following steps,
mixing polyvinyl alcohol with distilled water;
stirring and reacting at the water bath temperature of 98 ℃ at the rotating speed of 200 revolutions per minute;
and after the polyvinyl alcohol is completely dissolved in water, cooling to room temperature, dropwise adding dilute sulfuric acid, and adjusting the pH value to 2-3 to obtain the polyvinyl alcohol aqueous solution.
3. A process for the preparation of a polyvinyl alcohol-based composite material according to claim 1 or 2, characterized in that: the mass concentration of the polyvinyl alcohol aqueous solution is 10%.
4. A process for the preparation of a polyvinyl alcohol-based composite material according to claim 1 or 2, characterized in that: the preparation of the polyphenylene sulfide oligomer mixed solution comprises the following steps,
and mixing the polyphenylene sulfide oligomer and deionized water, and grinding for 30 minutes by using a homogenizer until no obvious particles exist macroscopically, thereby obtaining the polyphenylene sulfide oligomer mixed solution.
5. A process for the preparation of a polyvinyl alcohol-based composite material according to claim 1 or 2, characterized in that: the polyphenylene sulfide oligomer mixed solution is characterized in that the solid solution ratio in the polyphenylene sulfide mixed solution is 4%.
6. A process for the preparation of a polyvinyl alcohol-based composite material according to claim 1 or 2, characterized in that: the polyvinyl alcohol aqueous solution and the polyphenylene sulfide mixed solution are mixed and stirred, wherein the mixing and stirring speed is 160 r/min.
7. A process for the preparation of a polyvinyl alcohol-based composite material according to claim 1 or 2, characterized in that: and uniformly stirring, wherein the stirring time is 30min, and the stirring speed is 160 r/min.
8. A process for the preparation of a polyvinyl alcohol-based composite material according to claim 1 or 2, characterized in that: and standing at room temperature, wherein the standing time is 2-3 days.
9. A process for the preparation of a polyvinyl alcohol-based composite material according to claim 1 or 2, characterized in that: the mass ratio of the polyvinyl alcohol to the polyphenylene sulfide oligomer is 10:1, and the mass ratio of the glutaraldehyde to the polyphenylene sulfide oligomer is 0.8: 1.
10. A product obtained by the method for preparing a polyvinyl alcohol-based composite material according to any one of claims 1 to 9.
Technical Field
The invention belongs to the technical field of shape memory polymers, and particularly relates to a preparation method of a polyvinyl alcohol-based composite material and a product thereof.
Background
Shape Memory Polymers (SMP) are a type of stimuli-responsive smart material that can sense changes in external environmental factors (e.g., temperature, electromagnetic, light, solvent, etc.) and respond to such environmental changes by adjusting its own mechanical parameters (e.g., Shape, position, strain, etc.) to recover the polymer in a predetermined state. In the process of recovering the initial state of the SMP, external energy needs to be absorbed, so that the polymer is converted from a low-entropy thermodynamically unstable state to a high-entropy thermodynamically stable state, and the shape memory process of the SMP can be driven by physical conditions (such as thermal driving, acoustic driving, optical driving and the like) and chemical conditions (such as pH value driving and solution driving). Currently, Shape Memory Polymers (SMPs) can be classified into five categories according to the principle of shape recovery: thermal response type, solution response type, optical response type, electric response type, and magnetic induction type.
In recent years, shape memory polymers have been widely regarded as an important research object for multifunctional materials. Compared with other functional materials, the material has the advantages of rich raw materials, various varieties, wide range of conditions such as recovery temperature and the like; the deformation amount is large, the weight is light and durable, the corrosion is avoided, the coloring is easy, the packaging and the transportation are easy, and the application range is wide; easy processing, easy shaping and low energy consumption; the price is low, and is only 1 percent of that of the metal shape memory alloy; corrosion resistance, strong electrical insulation and good heat preservation effect.
At present, the shape memory polymer prepared by polyvinyl alcohol acetalization reaction has low fixation rate and recovery rate and poor mechanical property.
Disclosure of Invention
This section is for the purpose of summarizing some aspects of the invention and to briefly introduce some preferred embodiments. In this section, as well as in the abstract and the title of the invention of this application, simplifications or omissions may be made to avoid obscuring the purpose of the section, the abstract and the title, and such simplifications or omissions are not intended to limit the scope of the invention.
The present invention has been made keeping in mind the above and/or other problems occurring in the prior art.
Therefore, the invention aims to overcome the defects in the prior art and provide a preparation method of a polyvinyl alcohol-based composite material.
In order to solve the technical problems, the invention provides the following technical scheme: a preparation method of a polyvinyl alcohol-based composite material comprises the following steps,
preparing a polyvinyl alcohol aqueous solution;
preparing polyphenylene sulfide oligomer mixed liquor;
mixing and stirring a polyvinyl alcohol aqueous solution and a polyphenylene sulfide oligomer mixed solution, adding glutaraldehyde, uniformly stirring, and standing at room temperature to obtain the polyvinyl alcohol-based composite material; wherein the content of the first and second substances,
the mass ratio of the polyvinyl alcohol to the polyphenylene sulfide oligomer is 5-20: 1, and the mass ratio of the glutaraldehyde to the polyphenylene sulfide oligomer is 0.8-1: 1.
As a preferable embodiment of the preparation method of the polyvinyl alcohol-based composite material of the present invention, wherein: the preparation of the polyvinyl alcohol aqueous solution comprises the following steps,
mixing polyvinyl alcohol with distilled water;
stirring and reacting at the water bath temperature of 98 ℃ at the rotating speed of 200 revolutions per minute;
and after the polyvinyl alcohol is completely dissolved in water, cooling to room temperature, dropwise adding dilute sulfuric acid, and adjusting the pH value to 2-3 to obtain the polyvinyl alcohol aqueous solution.
As a preferable embodiment of the preparation method of the polyvinyl alcohol-based composite material of the present invention, wherein: the mass concentration of the polyvinyl alcohol aqueous solution is 10%.
As a preferable embodiment of the preparation method of the polyvinyl alcohol-based composite material of the present invention, wherein: the preparation of the polyphenylene sulfide oligomer mixed solution comprises the following steps,
and mixing the polyphenylene sulfide oligomer and deionized water, and grinding for 30 minutes by using a homogenizer until no obvious particles exist macroscopically, thereby obtaining the polyphenylene sulfide oligomer mixed solution.
As a preferable embodiment of the preparation method of the polyvinyl alcohol-based composite material of the present invention, wherein: the polyphenylene sulfide oligomer mixed solution is characterized in that the solid solution ratio in the polyphenylene sulfide mixed solution is 4%.
As a preferable embodiment of the preparation method of the polyvinyl alcohol-based composite material of the present invention, wherein: the polyvinyl alcohol aqueous solution and the polyphenylene sulfide mixed solution are mixed and stirred, wherein the mixing and stirring speed is 160 r/min.
As a preferable embodiment of the preparation method of the polyvinyl alcohol-based composite material of the present invention, wherein: and uniformly stirring, wherein the stirring time is 30min, and the stirring speed is 160 r/min.
As a preferable embodiment of the preparation method of the polyvinyl alcohol-based composite material of the present invention, wherein: and standing at room temperature, wherein the standing time is 2-3 days.
As a preferable embodiment of the preparation method of the polyvinyl alcohol-based composite material of the present invention, wherein: the mass ratio of the polyvinyl alcohol to the polyphenylene sulfide oligomer is 10:1, and the mass ratio of the glutaraldehyde to the polyphenylene sulfide oligomer is 0.8: 1.
Therefore, it is still another object of the present invention to overcome the disadvantages of the prior art and to provide a product prepared by the preparation method of the polyvinyl alcohol-based composite material.
The invention has the beneficial effects that:
the invention provides a preparation method of a polyvinyl alcohol-based composite material, which adopts polyvinyl alcohol and glutaraldehyde as raw materials, polyphenylene sulfide oligomer as an additive, under the state of aqueous solution, the hydroxyl group and aldehyde group of polyvinyl alcohol are subjected to acetal reaction through acid catalysis to form a six-membered ring structure, different polyvinyl alcohol molecular chains are connected together to form a three-dimensional network structure, and the PVA-PPS shape memory composite material is prepared; the compatibility of the polyphenylene sulfide molecules and the polyvinyl valeraldehyde is good, the crystallinity of the polyvinyl alcohol molecules is reduced, the hardness is reduced, and the toughness is improved; the thioether bond in the polyphenylene sulfide oligomer can form a hydrogen bond with the hydroxyl of polyvinyl alcohol, so that the number of crosslinking points in the material is increased, the shape fixing rate and the recovery rate of the PVA-PPS shape memory composite material are both improved, and the shape memory performance of the composite material is obviously superior to that of polyvinyl valeraldehyde.
The PVA-PPS shape memory composite material of the invention adopts polyphenylene sulfide oligomer as an additive for physical modification, which not only effectively utilizes the solid waste polyphenylene sulfide oligomer, reduces the inevitable accumulation of the solid waste in the production of polyphenylene sulfide, but also reduces the pollution to the surrounding environment, beautifies and protects the environment.
Drawings
In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings needed to be used in the description of the embodiments will be briefly introduced below, and it is obvious that the drawings in the following description are only some embodiments of the present invention, and it is obvious for those skilled in the art to obtain other drawings based on these drawings without inventive exercise. Wherein:
FIG. 1 is a graph showing experimental test conditions in example 1 of the present invention.
FIG. 2 is a graph showing the test results of the recovery process at 120 ℃ in example 1 of the present invention.
FIG. 3 is a graph showing experimental conditions in example 4 of the present invention.
FIG. 4 is a graph showing the results of the test of the recovery process at 120 ℃ in example 4 of the present invention.
FIG. 5 is a DSC of a material prepared without adding PPS;
FIG. 6 is a DSC of a material prepared with 5% PPS;
FIG. 7 is a DSC of a material made of 10% PPS;
FIG. 8 is a DSC of a material made of 20% PPS;
FIG. 9 is a graph comparing the relationship between the loss tangent angle (tan d) of samples with different PPS contents and the change of the temperature after blending of quantitative polyvinyl alcohol and glutaraldehyde;
FIG. 10 is a graph comparing the storage modulus (E0) of samples blended with different amounts of PPS and a fixed amount of polyvinyl alcohol, glutaraldehyde, as a function of temperature.
Detailed Description
In order to make the aforementioned objects, features and advantages of the present invention more comprehensible, specific embodiments thereof are described in detail below with reference to examples of the specification.
In the following description, numerous specific details are set forth in order to provide a thorough understanding of the present invention, but the present invention may be practiced in other ways than those specifically described and will be readily apparent to those of ordinary skill in the art without departing from the spirit of the present invention, and therefore the present invention is not limited to the specific embodiments disclosed below.
Furthermore, reference herein to "one embodiment" or "an embodiment" means that a particular feature, structure, or characteristic described in connection with the embodiment is included in at least one implementation of the invention. The appearances of the phrase "in one embodiment" in various places in the specification are not necessarily all referring to the same embodiment, nor are separate or alternative embodiments mutually exclusive of other embodiments.
The experimental medicine and the experimental instrument of the invention are shown in the table 1
TABLE 1 Experimental drugs
TABLE 2 Experimental instruments
The material performance detection of the invention:
the product related to the experimental study belongs to a polymer memory composite material, and is tested by shape memory performance, DSC and DMA.
Shape memory detection
The four groups of samples were: the addition amount of the polyphenylene sulfide oligomer is based on polyvinyl alcohol in 1 st group (0% -PPS), 2 nd group (5% -PPS), 3 rd group (10% -PPS) and 4 th group (20% -PPS).
The experimental steps are as follows:
(1) the previously prepared product was cut into a sample bar having dimensions of 20mm × 5mm × 2mm (length × width × thickness).
(2) Placing the sample strip on a watch glass for drying (to remove water in the system), setting the temperature at 100 ℃, raising the temperature to 120 ℃ after the sample strip has no obvious water, preserving the temperature for 30min, taking out the sample strip, folding the sample strip in half, fixing the sample strip by using an external force, then placing the sample strip in an ice-water mixed bath for rapidly reducing the temperature, fixing the deformation, and preserving the temperature for 10 min.
(3) The sample bar was taken out and the external force was removed, and the sample bar was left to stand at room temperature for 30min, and the angle at which the sample bar was folded in half was measured, and then the sample bar was placed in a drying oven at a temperature of 120 ℃. And (5) rapidly closing the box door, and observing and recording the sample strip recovery time and the recovery process.
Shape fixation rate calculation formula:
θn-angle of the sample bar at room temperature;
θmfold-over deformation angle 180 °.
Shape recovery rate calculation formula:
εn-is a return angle;
εmfold-over deformation angle 180 °.
DSC Performance test
Sample preparation: placing a small amount of sample in a drying oven, setting the temperature to be 105 ℃, preserving the heat, drying until the weight of the sample is constant, and then testing;
temperature range: 25-300 ℃.
DMA Performance testing
Spline size: 10mm × 10mm × 2mm (length × width × thickness), tested in shear mode;
and (3) testing conditions are as follows: the frequency is 1Hz, the temperature rising speed is 3 ℃/min, and the temperature range is 25-145 ℃.
Example 1
The embodiment provides a preparation method of a polyvinyl alcohol-based composite material, which comprises the following steps:
(1) preparing 10% polyvinyl alcohol aqueous solution:
weighing 20g of polyvinyl alcohol by using an electronic balance, pouring the polyvinyl alcohol into a dry three-neck flask, weighing 180g of deionized water, mixing the polyvinyl alcohol and the deionized water together, and adjusting the temperature of a water bath to 98 ℃;
a condensing device and a magnetic stirrer are arranged, and the rotating speed is set to be 200 revolutions per minute;
and stopping heating after the polyvinyl alcohol is completely dissolved in water, slowly dropwise adding dilute hydrochloric acid when the polyvinyl alcohol aqueous solution is cooled to room temperature, adjusting the pH to 2-3, pouring into a volumetric flask, and sealing and storing in a cool and dry place.
(2) Preparing polyphenylene sulfide oligomer mixed liquid:
weighing 10g of polyphenylene sulfide oligomer into a beaker by using an electronic balance, washing and mixing by using deionized water, and grinding for 30 minutes by using a homogenizer until no obvious particles exist macroscopically;
measuring the solid content of the polyphenylene sulfide oligomer mixed solution: weighing 57.60 g of a clean watch glass, dripping 1g of the polyphenylene sulfide oligomer mixed solution on the watch glass, putting the watch glass in a 105 ℃ constant-temperature drying oven, heating and drying to constant weight, wherein the measured mass is 57.64g, and the solid content of the polyphenylene sulfide oligomer mixed solution is 4% by calculation.
(3) Respectively weighing 20g of 10% PVA aqueous solution and 2.5g of 4% PPS mixed solution, pouring the mixture into a 100mL beaker, stirring the mixture by using a magnetic stirrer, regulating the rotation speed to 160r/min, slowly dripping 0.8g of glutaraldehyde after the mixture is uniformly mixed, closing the stirrer after stirring the mixture for 30min, pouring the mixture into a mold, standing the mixture for 2 to 3 days at room temperature, taking the mixture out after molding, and washing the mixture by using deionized water to obtain the polyvinyl alcohol-based composite material.
The test condition diagram of the shape memory experiment is shown in fig. 1, wherein, the diagram (a) is the initial state of the material, and the diagram (b) is the fixed state diagram after the material is deformed.
The test results of the recovery process at 120 ℃ are shown in fig. 2, in which (a) is a graph of the recovery process at 0s for the material, (b) is a graph of the recovery process at 28s for the material, (c) is a graph of the recovery process at 36s for the material, and (d) is a graph of the recovery process at 63s for the material.
As can be seen from FIGS. 1 and 2, when the PPS content is 5%, the fixed angle of the splines is 177 °, the recovery angle is 169 °, and the recovery time is 63 s.
Example 2
The embodiment provides a preparation method of a polyvinyl alcohol-based composite material, which comprises the following steps:
(1) preparing 10% polyvinyl alcohol aqueous solution:
weighing 20g of polyvinyl alcohol by using an electronic balance, pouring the polyvinyl alcohol into a dry three-neck flask, weighing 180g of deionized water, mixing the polyvinyl alcohol and the deionized water together, and adjusting the temperature of a water bath to 98 ℃;
a condensing device and a magnetic stirrer are arranged, and the rotating speed is set to be 200 revolutions per minute;
and stopping heating after the polyvinyl alcohol is completely dissolved in water, slowly dropwise adding dilute hydrochloric acid when the polyvinyl alcohol aqueous solution is cooled to room temperature, adjusting the pH to 2-3, pouring into a volumetric flask, and sealing and storing in a cool and dry place.
(2) Preparing polyphenylene sulfide oligomer mixed liquid:
weighing 10g of polyphenylene sulfide oligomer into a beaker by using an electronic balance, washing and mixing by using deionized water, and grinding for 30 minutes by using a homogenizer until no obvious particles exist macroscopically;
measuring the solid content of the polyphenylene sulfide oligomer mixed solution: weighing 57.60 g of a clean watch glass, dripping 1g of the polyphenylene sulfide oligomer mixed solution on the watch glass, putting the watch glass in a 105 ℃ constant-temperature drying oven, heating and drying to constant weight, wherein the measured mass is 57.64g, and the solid content of the polyphenylene sulfide oligomer mixed solution is 4% by calculation.
(3) Respectively weighing 20g of 10% PVA aqueous solution and 10g of 4% PPS mixed solution, pouring the mixture into a 100mL beaker, stirring the mixture by using a magnetic stirrer, adjusting the rotation speed to 160r/min, slowly dripping 0.8g of glutaraldehyde after the mixture is uniformly mixed, closing the stirrer after stirring for 30min, pouring the mixture into a mold, standing the mixture at room temperature for 2-3 days, taking out the mixture after molding, and washing the mixture by using deionized water to obtain the polyvinyl alcohol-based composite material.
Example 3
The embodiment provides a preparation method of a polyvinyl alcohol-based composite material, which comprises the following steps:
(1) preparing 10% polyvinyl alcohol aqueous solution:
weighing 20g of polyvinyl alcohol by using an electronic balance, pouring the polyvinyl alcohol into a dry three-neck flask, weighing 180g of deionized water, mixing the polyvinyl alcohol and the deionized water together, and adjusting the temperature of a water bath to 98 ℃;
a condensing device and a magnetic stirrer are arranged, and the rotating speed is set to be 200 revolutions per minute;
and stopping heating after the polyvinyl alcohol is completely dissolved in water, slowly dropwise adding dilute hydrochloric acid when the polyvinyl alcohol aqueous solution is cooled to room temperature, adjusting the pH to 2-3, pouring into a volumetric flask, and sealing and storing in a cool and dry place.
(2) Preparing polyphenylene sulfide oligomer mixed liquid:
weighing 10g of polyphenylene sulfide oligomer into a beaker by using an electronic balance, washing and mixing by using deionized water, and grinding for 30 minutes by using a homogenizer until no obvious particles exist macroscopically;
measuring the solid content of the polyphenylene sulfide oligomer mixed solution: weighing 57.60 g of a clean watch glass, dripping 1g of the polyphenylene sulfide oligomer mixed solution on the watch glass, putting the watch glass in a 105 ℃ constant-temperature drying oven, heating and drying to constant weight, wherein the measured mass is 57.64g, and the solid content of the polyphenylene sulfide oligomer mixed solution is 4% by calculation.
(3) Respectively weighing 20g of 10% PVA solution and 5g of 4% PPS mixed solution, pouring the mixture into a 100ml beaker, stirring the mixture by using an electromagnetic stirrer, regulating the rotation speed to 160r/min, slowly dripping 0.8g of glutaraldehyde, closing the stirrer after stirring for 30min, pouring the mixture into a mold, standing the mold for 2 to 3 days at room temperature, taking out the molded product, and washing the molded product by using deionized water to obtain the polyvinyl alcohol-based composite material.
At a PPS content of 10%, the bars had a constant angle of 178 °, a recovery angle of about 172 °, a shape recovery of 95.56%, and a recovery time of 21 seconds.
Example 4
The embodiment provides a preparation method of a polyvinyl alcohol-based composite material, which comprises the following steps:
(1) preparing 10% polyvinyl alcohol aqueous solution:
weighing 20g of polyvinyl alcohol by using an electronic balance, pouring the polyvinyl alcohol into a dry three-neck flask, weighing 180g of deionized water, mixing the polyvinyl alcohol and the deionized water together, and adjusting the temperature of a water bath to 98 ℃;
a condensing device and a magnetic stirrer are arranged, and the rotating speed is set to be 200 revolutions per minute;
and stopping heating after the polyvinyl alcohol is completely dissolved in water, slowly dropwise adding dilute hydrochloric acid when the polyvinyl alcohol aqueous solution is cooled to room temperature, adjusting the pH to 2-3, pouring into a volumetric flask, and sealing and storing in a cool and dry place.
(2) Weighing 20g of 10% PVA aqueous solution, pouring the PVA aqueous solution into a 100ml beaker, slowly dropwise adding 0.8g of glutaraldehyde under magnetic stirring at the rotating speed of 160r/min, stirring for 30min, closing a stirrer, pouring the mixture into a mold, standing for 2-3 days at room temperature, taking out after molding, and washing with deionized water to obtain the polyvinyl alcohol-based composite material.
The experimental test conditions are shown in fig. 3, wherein (a) is the initial state of the material, and (b) is the fixed state of the deformed material.
The results of the recovery process at 120 ℃ are shown in FIG. 4, in which (a) is a graph of the recovery process for material 0s, (b) is a graph of the recovery process for material 60s, (c) is a graph of the recovery process for material 90s, and (d) is a graph of the recovery process for material 148 s.
As can be seen from fig. 3 and 4, when PPS was not added, the measured recovery angle was about 165 °, the recovery rate of the spline was 91.67%, the fixed angle was 170 °, and the recovery time was 148 s.
The shape memory effect of the materials obtained in examples 1 to 4 was summarized in Table 3.
TABLE 3
As can be seen from Table 3, the four groups of materials all have shape memory properties, and the shape recovery rate both reach more than 90%. In the shape memory material, a six-membered ring skeleton structure formed by acetalization reaction of polyvinyl alcohol and glutaraldehyde under the catalysis of acid is used as a stationary phase, a main chain of polyethylene glycol is used as a reversible phase, and the glass transition temperature of the polyethylene glycol is the conversion temperature. When the material is in a permanent shape, the structure of the molecular chain of the shape memory polymer has the maximum value of entropy, namely the molecular chain is in a thermodynamic stable state; when heated to a temperature above the transition temperature, the segmental motion is greatly activated; when a deformation load is applied externally, the structure of the chain is changed, so that the macroscopic shape is changed to enter a low-entropy state; when the shape memory polymer is cooled below the transition temperature, the low entropy state (or temporary shape) is restricted in motion due to the motion of the segments being frozen, resulting in the fixation of the macroscopic shape; when the polymer is reheated above the transition temperature without stress, the molecular chain motion is again activated and the molecular weight is again brought to the state of maximum entropy (i.e. reverts to a permanent shape).
As can be seen from Table 3, the polyvinyl alcohol-based composite material with the polyphenylene sulfide oligomer added thereto has good shape memory, short recovery time, high recovery rate, and significantly shorter recovery time than the material without the polyphenylene sulfide oligomer added thereto. The polyphenylene sulfide oligomer and the polyvinyl alcohol are high molecular compounds with larger polarity, and the compatibility is better after the polyphenylene sulfide oligomer and the polyvinyl alcohol are mixed; the thioether bond in the polyphenylene sulfide oligomer can form a hydrogen bond with the hydroxyl of the polyvinyl alcohol, the acting force of the hydrogen bond is strong, so that the number of crosslinking points in the material is increased, namely, the driving force in the shape recovery process is enhanced, and the shape recovery process has the advantages of short required time and high recovery rate. Therefore, the shape memory performance of the PPS-PVA shape memory material is obviously superior to that of a polyvinyl alcohol material without added polyphenylene sulfide oligomer. Among the four groups of PPS-PVA shape memory composite materials, when the PPS PVA is 1:10, the shape fixing rate of the material is 98.89%, the shape recovery rate is 95.56, the recovery time is 21s, and the shape memory performance is optimal.
Analysis of DSC detection results:
FIG. 5 is a DSC of a material prepared without PPS addition;
FIG. 6 is a DSC of a material prepared with 5% PPS;
FIG. 7 is a DSC of a material made of 10% PPS;
FIG. 8 is a DSC of a material obtained from 20% PPS group.
It can be seen that the baseline shift that occurs around 60 ℃ in the temperature-increasing scan curve is due to the glass transition of the polymer, which corresponds to the loss tangent angle that occurs at this temperature in the DMA thermal curve. In the reaction process, when the polyvinyl alcohol uses glutaraldehyde as a cross-linking agent, the chemical cross-linking reaction is easy to carry out, because the adjacent side chain hydroxyl and two aldehyde groups of the glutaraldehyde have high reaction capacity, a hemiacetal or acetal structure with a six-membered ring is formed, the higher chemical cross-linking point reduces the number of the hydroxyl so as to weaken the forming capacity of a hydrogen bond, and the improvement of the cross-linking density shortens the length of a molecular chain between the cross-linking point and the cross-linking point, reduces the flexibility of the molecular chain, and reduces the crystallinity of the polymer. In the experimental group after the addition of PPS, it was found that the PVA melting peak was shifted to the left, and the PPS melting peak was shifted to the right as the amount of PPS added was increased.
Dynamic thermomechanical property results analysis:
FIG. 9 is a graph comparing the relationship between the loss tangent angle (tan d) of samples with different PPS contents and the change of the temperature after blending of quantitative polyvinyl alcohol and glutaraldehyde;
FIG. 10 is a graph comparing the storage modulus (E0) of samples blended with different amounts of PPS and a fixed amount of polyvinyl alcohol, glutaraldehyde, as a function of temperature.
In general, the polymers are below TgThe higher modulus at (glass transition temperature) is mainly due to the glassy and elastic nature of the crystalline and amorphous regions of the polymer. PVA is a typical partially crystalline polymer, and due to strong hydrogen bonding formed between hydroxyl groups of side chains, the PPS-PVA material has higher storage modulus at lower temperature due to higher physical interaction formed between polymer chains. As can be seen from the figure, the initial modulus of the PPS PVA-1: 10 sample strip is obviously higher than that of the other three groups, the modulus change value is also the largest near the transition temperature, and for the shape memory polymer, the larger the storage modulus change value near the transition temperature is, the better the shape memory performance is, thus the PPS PVA-1: 10 sample strip is just combined with the test of the shape memory performanceThe results were consistent.
A relaxation peak was observed in fig. 10 at around 60 ℃. This lower intensity peak can be considered to be due to the glass transition of the PVA molecular chains.
It should be noted that the above-mentioned embodiments are only for illustrating the technical solutions of the present invention and not for limiting, and although the present invention has been described in detail with reference to the preferred embodiments, it should be understood by those skilled in the art that modifications or equivalent substitutions may be made on the technical solutions of the present invention without departing from the spirit and scope of the technical solutions of the present invention, which should be covered by the claims of the present invention.