阅读说明：本技术 一种可生物降解的高分子包装材料 (Biodegradable high-molecular packaging material ) 是由 牛宏伟 于 2021-09-03 设计创作，主要内容包括：本发明属于生物降解高分子材料技术领域,特别涉及一种可生物降解的高分子包装材料。由改性聚乙烯醇、稳定剂、增塑剂和助剂制备而成,利用戊二醛对聚乙烯醇进行改性,将戊二醛一端的醛基氧化为羧基与聚乙烯醇分子链上的羟基发生酯化反应,得到改性聚乙烯醇,避免了聚乙烯醇分子链上大量分子内和分子间氢键的形成,同时在改性聚乙烯醇分子链上引入了活泼醛基,使得合成的可生物降解的高分子包装材料在具有优异力学性能的同时能够有效的抑制大肠杆菌和金黄色葡萄球菌,且具有良好的降解速率。(The invention belongs to the technical field of biodegradable high polymer materials, and particularly relates to a biodegradable high polymer packaging material. The modified polyvinyl alcohol is prepared from modified polyvinyl alcohol, a stabilizer, a plasticizer and an auxiliary agent, wherein the polyvinyl alcohol is modified by glutaraldehyde, aldehyde groups at one end of the glutaraldehyde are oxidized into carboxyl groups to be subjected to esterification reaction with hydroxyl groups on a polyvinyl alcohol molecular chain, so that the modified polyvinyl alcohol is obtained, the formation of a large number of intra-molecular and intermolecular hydrogen bonds on the polyvinyl alcohol molecular chain is avoided, and meanwhile, active aldehyde groups are introduced on the modified polyvinyl alcohol molecular chain, so that the synthesized biodegradable high polymer packaging material has excellent mechanical properties, can effectively inhibit escherichia coli and staphylococcus aureus and has a good degradation rate.)

1. A biodegradable high molecular packaging material is characterized in that the biodegradable high molecular packaging material is prepared from modified polyvinyl alcohol, a stabilizer, a plasticizer and an auxiliary agent;

the chemical structural formula of the modified polyvinyl alcohol is shown as formula I:

2. the biodegradable polymer packaging material as claimed in claim 1, wherein the modified polyvinyl alcohol is prepared by the following steps:

s1: mixing glutaraldehyde, an extracting agent and a diluent, adding a catalyst, heating and stirring, continuously introducing air into the mixture, dropwise adding a NaOH solution into the mixture in the reaction process, adjusting the pH value of the solution to 7.5, and reacting for 4-6 hours;

s2: filtering the mixed solution after the reaction in the step S1, standing to obtain a standing mother solution, carrying out back extraction on the standing mother solution by using water, reducing the temperature, and precipitating crystals from the solution after the back extraction;

s3: and adding polyvinyl alcohol into deionized water, heating and stirring, adding copper sulfate after the polyvinyl alcohol is dissolved, slowly adding the crystal obtained in the step S2, reacting for 4-6h, and filtering to obtain the modified polyvinyl alcohol.

3. The biodegradable high molecular packaging material of claim 2, wherein the modified polyvinyl alcohol is prepared by the following steps:

s1: mixing 80-100 parts of glutaraldehyde, 60-80 parts of tributylamine as an extracting agent and 60-80 parts of n-butyl alcohol as a diluent by weight, and adding 6-10 parts of Pd/SiO as a catalyst by weight₂Heating and stirring at the temperature of 55-65 ℃, continuously introducing air into the mixture, dropwise adding 0.05mol/L NaOH solution into the mixture in the reaction process, testing the pH value of the solution by using a pH meter, adjusting the pH value of the solution to 7.5, and reacting for 4-6 hours;

s2: filtering the mixed solution after the reaction in the step S1 is finished, standing the filtrate for 18-24h to obtain a mother solution after standing, carrying out back extraction on the mother solution after standing by using water, reducing the temperature to-5 ℃, and precipitating crystals from the solution after the back extraction;

s3: adding 85-95 parts by weight of polyvinyl alcohol into 130-150 parts by weight of deionized water, heating and stirring at 65-75 ℃, adding 6-10 parts by weight of copper sulfate after the polyvinyl alcohol is dissolved, slowly adding 75-85 parts by weight of the crystal obtained in the step S2, reacting for 4-6h, and filtering to obtain the modified polyvinyl alcohol.

4. The biodegradable polymer packaging material as claimed in claim 1, wherein the stabilizer is one or more selected from zinc stearate, calcium stearate, diglycidyl terephthalate, butyl epoxystearate, triphenyl phosphite, tridecyl phosphite, trisnonylphenyl phosphite, and trioctyl phosphite;

the plasticizer is one or a mixture of several of diisononyl phthalate, diisodecyl phthalate, tributyl citrate and trioctyl citrate;

the auxiliary agent is one or a mixture of several of dibutyl hydroxy toluene, propyl gallate, butyl hydroxy anisol and tert-butyl hydroquinone.

5. The biodegradable high polymer packaging material of claim 1, which is prepared from the following raw materials in parts by weight:

70-80 parts of modified polyvinyl alcohol;

10-18 parts of a stabilizer;

8-16 parts of a plasticizer;

4-10 parts of an auxiliary agent.

6. The biodegradable high polymer packaging material of claim 1, which is prepared from the following raw materials in parts by weight:

75 parts of modified polyvinyl alcohol;

12 parts of a stabilizer;

14 parts of a plasticizer;

and 6 parts of an auxiliary agent.

7. The method for preparing biodegradable polymer packaging material according to any one of claims 1-6, wherein the method comprises the following steps:

adding the modified polyvinyl alcohol, the stabilizer, the plasticizer and the auxiliary agent into a stirrer in proportion, stirring at the speed of 800-; and adding the uniformly mixed raw materials into a double-screw extruder, extruding and granulating to obtain the biodegradable high polymer packaging material.

8. Use of a biodegradable polymeric packaging material according to any of claims 1-6, in the packaging field of consumer goods, chemical industry, building materials, food additives and medicine.

Technical Field

The invention relates to the technical field of biodegradable high polymer materials, in particular to a biodegradable high polymer packaging material.

Background

With the development of society, various polymer materials are applied to daily production and life. However, these materials are difficult to naturally degrade and cause serious pollution to the environment, which is not in accordance with the concept of "green development". In order to solve the pollution problem, the research on biodegradable polymer materials is the focus of attention. The biodegradable polymer generally refers to a polymer material having a certain mechanical strength and capable of being decomposed into low molecular compounds in the natural environment, in whole or in part, by microorganisms such as bacteria, molds (fungi), and algae, without causing environmental pollution. It has the following characteristics: can be made into compost to return to nature; the volume is reduced due to degradation, and the service life of a landfill site is prolonged; the problem that common plastic bags need to be burnt is solved, and the emission of harmful gases is reduced; the harm to wild animals and plants due to random discarding can be reduced; convenient storage and transportation, and no need of light shielding.

There are three types of polymer biodegradation modes. The first is to utilize microbe to erode the polymer material, promote the microbe to destroy the structure of the polymer, and degrade the whole polymer material. The second is to utilize the characteristics of biological enzyme to act on the polymer material to promote the microorganism to erode the molecular chain of the polymer. The third degradation method is accomplished by using the combination of microbes and polymers. The degradation of the polymer in this method does not make the polymer material disappear completely, but generates new substances under the action of microorganisms, and the process is complicated.

Chinese patent 201010294691.2 discloses a starch-based thermoplastic biodegradable material and a preparation method thereof, which comprises plant starch, a modified plasticizing auxiliary agent and a degradable high molecular compound, wherein macromolecules of the plant starch are subjected to catalytic modification in a mixing device through the modified plasticizing auxiliary agent, so that the molecular structure of the plant starch is reduced; and then recombining the starch micromolecules which are fully modified. The prepared starch-based thermoplastic biodegradable material is water-resistant and oil-resistant, has good weather resistance and has excellent thermoplastic forming performance.

Chinese patent 200810123123.9 discloses a microcapsule expansion flame-retardant starch-based degradable material and a preparation method thereof, wherein starch is mixed with a plasticizer and a compatibilizer, and a biodegradable high molecular compound, a microcapsule expansion flame retardant and a flame-retardant catalyst are added to obtain the expansion flame-retardant starch-based degradable material. The obtained product has excellent flexibility and mechanical property; the water resistance and the oil resistance are better; is non-toxic and harmless, and can be completely biodegraded; the flame retardant property is better; can be used in the fields of packaging, laminating materials, sports sanitary products and the like.

Disclosure of Invention

In order to obtain a high polymer packaging material which can meet the packaging requirement and realize automatic degradation, the invention provides a biodegradable high polymer packaging material which has excellent mechanical property and can effectively inhibit escherichia coli and staphylococcus aureus.

The technical scheme for solving the problems is as follows:

a biodegradable high-molecular packing material is prepared from modified polyvinyl alcohol, stabilizer, plasticizer and assistant;

the chemical structural formula of the modified polyvinyl alcohol is shown as formula I:

as a further improvement of the invention, the preparation method of the modified polyvinyl alcohol comprises the following steps:

s1: mixing glutaraldehyde, an extracting agent and a diluent, adding a catalyst, heating and stirring, continuously introducing air into the mixture, dropwise adding a NaOH solution into the mixture in the reaction process, adjusting the pH value of the solution to 7.5, and reacting for 4-6 hours;

s2: filtering the mixed solution after the reaction in the step S1, standing to obtain a standing mother solution, carrying out back extraction on the standing mother solution by using water, reducing the temperature, and precipitating crystals from the solution after the back extraction;

s3: and adding polyvinyl alcohol into deionized water, heating and stirring, adding copper sulfate after the polyvinyl alcohol is dissolved, slowly adding the crystal obtained in the step S2, reacting for 4-6h, and filtering to obtain the modified polyvinyl alcohol.

The invention has the following beneficial effects:

the polyvinyl alcohol is modified by glutaraldehyde, the aldehyde group at one end of the glutaraldehyde is oxidized into carboxyl and is subjected to esterification reaction with hydroxyl on a polyvinyl alcohol molecular chain to obtain the modified polyvinyl alcohol, the formation of a large number of intra-molecular and intermolecular hydrogen bonds on the polyvinyl alcohol molecular chain is avoided, and meanwhile, the active aldehyde group is introduced on the modified polyvinyl alcohol molecular chain, so that the synthesized biodegradable high-molecular packaging material has excellent mechanical property, can effectively inhibit escherichia coli and staphylococcus aureus, and has good degradation rate.

Detailed Description

The technical solutions in the embodiments of the present application are clearly and completely described below, and it is obvious that the described embodiments are only a part of the embodiments of the present application, and not all embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present application.

Example 1

A biodegradable high-molecular packing material is prepared from modified polyvinyl alcohol, stabilizer, plasticizer and assistant;

the preparation method of the modified polyvinyl alcohol comprises the following steps:

s1: mixing 80 parts by weight of glutaraldehyde, 60 parts by weight of tributylamine as an extracting agent and 60 parts by weight of n-butyl alcohol as a diluent, and adding 6 parts by weight of Pd/SiO as a catalyst₂Heating and stirring the mixture at the temperature of 55 ℃, continuously introducing air into the mixture, and dropwise adding 0.05 mol/ml-based on the pH value of the mixture during the reactionLNaOH solution, using a pH meter to test the pH value of the solution, adjusting the pH value of the solution to 7.5, reacting for 4 hours, and oxidizing aldehyde groups at one end of glutaraldehyde into carboxyl groups after the reaction is finished, namely, one end of the reacted product is carboxyl groups, and the other end of the reacted product is aldehyde groups;

s2: filtering the mixed solution after the reaction in the step S1 is finished, standing the filtrate for 18h to obtain a standing mother solution, carrying out back extraction on the standing mother solution by using water, reducing the temperature to-5 ℃, and precipitating crystals from the solution after the back extraction;

s3: adding 85 parts by weight of polyvinyl alcohol into 130 parts by weight of deionized water, heating and stirring at the temperature of 65 ℃, adding 6 parts by weight of copper sulfate after the polyvinyl alcohol is dissolved, slowly adding 75 parts by weight of the crystal obtained in the step S2, carrying out esterification reaction, filtering after reacting for 4 hours, and removing the catalyst copper sulfate to obtain the modified polyvinyl alcohol. The copper sulfate is adopted as the catalyst, and because the copper sulfate is difficult to dissolve in reactants and products, the copper sulfate is easy to remove after the reaction is finished, the separation process is simplified, the separated copper sulfate can be reused, the cost is saved, and the chemical structural formula of the obtained product is shown as a formula I:

the polyvinyl alcohol can be used as a vinyl polymer for carbon source and energy source utilization by bacteria, can be degraded by 75% in 46 days under the action of the bacteria and enzyme, and belongs to a biodegradable high molecular material. However, polyvinyl alcohol contains a large number of hydroxyl groups, can form a large number of intramolecular and intermolecular hydrogen bonds, has a melting temperature very close to a decomposition temperature, and is difficult to be thermoplastically processed. In the invention, the polyvinyl alcohol is modified by glutaraldehyde, thereby realizing the improvement of the related performance of the polyvinyl alcohol. Glutaraldehyde has relatively active aldehyde groups that can react with the cell wall surface, causing protein coagulation resulting in bacterial death. Mixing glutaraldehyde, tributylamine and n-butanol under the condition of introducing air, and adding catalyst Pd/SiO₂Under the heating condition, aldehyde group at one end of glutaraldehyde is oxidized into carboxyl group. In the reaction process, tributylamine is used as an extractant, so that one end is oxidized into carboxylThe glutaraldehyde enters the organic phase to avoid further oxidation, so that the reaction is carried out towards the direction beneficial to the product, and the conversion rate of the glutaraldehyde and the selectivity of the product are improved. And the addition of the n-butyl alcohol can be complexed with the tributylamine, so that the layering speed of the tributylamine is improved. In step S3, polyvinyl alcohol undergoes an esterification reaction with the crystal obtained in step S2 under the catalysis of copper sulfate, and hydroxyl groups on the polyvinyl alcohol react, so that formation of a large number of intra-and intermolecular hydrogen bonds is avoided, and subsequent thermoplastic processing is facilitated.

A biodegradable high polymer packaging material is prepared from the following raw materials in parts by weight: 70 parts of modified polyvinyl alcohol; 10 parts of a stabilizer; 8 parts of a plasticizer; and 4 parts of an auxiliary agent. Wherein the stabilizer is zinc stearate; the plasticizer is prepared by mixing diisononyl phthalate and trioctyl citrate according to the weight ratio of 1: 1; the auxiliary agent is propyl gallate.

A preparation method of a biodegradable high polymer packaging material comprises the following steps: weighing the modified polyvinyl alcohol, the stabilizer, the plasticizer and the auxiliary agent according to the proportion, adding the weighed materials into a stirrer, and stirring for 15min at the stirring speed of 800 r/min; adding the uniformly mixed raw materials into a double-screw extruder, extruding and granulating at the temperature of 120-160 ℃ to obtain the biodegradable polymer packaging material.

The application of biodegradable high molecular packing material includes packing commodity, chemical industry, building material, food additive and medicine.

Example 2

A biodegradable high-molecular packing material is prepared from modified polyvinyl alcohol, stabilizer, plasticizer and assistant;

the preparation method of the modified polyvinyl alcohol comprises the following steps:

s1: mixing 100 weight parts of glutaraldehyde, 80 weight parts of tributylamine as an extracting agent and 80 weight parts of n-butyl alcohol as a diluent, and adding 10 weight parts of Pd/SiO as a catalyst₂AddingThermally stirring, heating to 65 ℃, continuously introducing air into the solution, dropwise adding 0.05mol/L NaOH solution into the solution in the reaction process, testing the pH of the solution by using a pH meter, adjusting the pH of the solution to 7.5, reacting for 6 hours, and oxidizing aldehyde groups at one end of glutaraldehyde into carboxyl groups after the reaction is finished, namely one end of a product after the reaction is carboxyl and the other end of the product is aldehyde groups;

s2: filtering the mixed solution after the reaction in the step S1 is finished, standing the filtrate for 18h to obtain a standing mother solution, carrying out back extraction on the standing mother solution by using water, reducing the temperature to-5 ℃, and precipitating crystals from the solution after the back extraction;

s3: adding 95 parts by weight of polyvinyl alcohol into 150 parts by weight of deionized water, heating and stirring at the temperature of 75 ℃, adding 10 parts by weight of copper sulfate after the polyvinyl alcohol is dissolved, slowly adding 85 parts by weight of the crystal obtained in the step S2, carrying out esterification reaction, filtering after 6 hours of reaction, and removing the catalyst copper sulfate to obtain the modified polyvinyl alcohol. The copper sulfate is used as the catalyst, and is difficult to dissolve in reactants and products, so that the copper sulfate is easy to remove after the reaction is finished, the separation process is simplified, the separated copper sulfate can be repeatedly used, and the cost is saved.

A biodegradable high polymer packaging material is prepared from the following raw materials in parts by weight: 70 parts of modified polyvinyl alcohol; 10 parts of a stabilizer; 8 parts of a plasticizer; and 4 parts of an auxiliary agent. Wherein the stabilizer is zinc stearate; the plasticizer is prepared by mixing diisononyl phthalate and trioctyl citrate according to the weight ratio of 1: 1; the auxiliary agent is propyl gallate.

A preparation method of a biodegradable high polymer packaging material comprises the following steps: weighing the modified polyvinyl alcohol, the stabilizer, the plasticizer and the auxiliary agent according to the proportion, adding the weighed materials into a stirrer, and stirring for 15min at the stirring speed of 800 r/min; adding the uniformly mixed raw materials into a double-screw extruder, extruding and granulating at the temperature of 120-160 ℃ to obtain the biodegradable polymer packaging material.

The application of biodegradable high molecular packing material includes packing commodity, chemical industry, building material, food additive and medicine.

Example 3

A biodegradable high-molecular packing material is prepared from modified polyvinyl alcohol, stabilizer, plasticizer and assistant;

the preparation method of the modified polyvinyl alcohol comprises the following steps:

s1: mixing 80 parts by weight of glutaraldehyde, 60 parts by weight of tributylamine as an extracting agent and 60 parts by weight of n-butyl alcohol as a diluent, and adding 6 parts by weight of Pd/SiO as a catalyst₂Heating and stirring, wherein the heating temperature is 55 ℃, continuously introducing air into the solution, dropwise adding 0.05mol/L NaOH solution into the solution in the reaction process, testing the pH value of the solution by using a pH meter, adjusting the pH value of the solution to 7.5, reacting for 4 hours, and oxidizing aldehyde group at one end of glutaraldehyde into carboxyl after the reaction is finished, namely one end of the reacted product is carboxyl and the other end is aldehyde group.

S2: filtering the mixed solution after the reaction in the step S1 is finished, standing the filtrate for 18h to obtain a standing mother solution, carrying out back extraction on the standing mother solution by using water, reducing the temperature to-5 ℃, and precipitating crystals from the solution after the back extraction;

s3: adding 85 parts by weight of polyvinyl alcohol into 130 parts by weight of deionized water, heating and stirring at the temperature of 65 ℃, adding 6 parts by weight of copper sulfate after the polyvinyl alcohol is dissolved, slowly adding 75 parts by weight of the crystal obtained in the step S2, carrying out esterification reaction, filtering after reacting for 4 hours, and removing the catalyst copper sulfate to obtain the modified polyvinyl alcohol. The copper sulfate is used as the catalyst, and is difficult to dissolve in reactants and products, so that the copper sulfate is easy to remove after the reaction is finished, the separation process is simplified, the separated copper sulfate can be repeatedly used, and the cost is saved.

A biodegradable high polymer packaging material is prepared from the following raw materials in parts by weight: 80 parts of modified polyvinyl alcohol; 18 parts of a stabilizer; 16 parts of a plasticizer; and 10 parts of an auxiliary agent. Wherein the stabilizer is zinc stearate; the plasticizer is prepared by mixing diisononyl phthalate and trioctyl citrate according to the weight ratio of 1: 1; the auxiliary agent is propyl gallate.

A preparation method of a biodegradable high polymer packaging material comprises the following steps: weighing the modified polyvinyl alcohol, the stabilizer, the plasticizer and the auxiliary agent according to the proportion, adding the weighed materials into a stirrer, and stirring for 20min at the stirring speed of 1000 r/min; adding the uniformly mixed raw materials into a double-screw extruder, extruding and granulating at the temperature of 120-160 ℃ to obtain the biodegradable polymer packaging material.

The application of biodegradable high molecular packing material includes packing commodity, chemical industry, building material, food additive and medicine.

Example 4

A biodegradable high-molecular packing material is prepared from modified polyvinyl alcohol, stabilizer, plasticizer and assistant;

the preparation method of the modified polyvinyl alcohol comprises the following steps:

s1: mixing 80 parts by weight of glutaraldehyde, 60 parts by weight of tributylamine as an extracting agent and 60 parts by weight of n-butyl alcohol as a diluent, and adding 6 parts by weight of Pd/SiO as a catalyst₂Heating and stirring, wherein the heating temperature is 55 ℃, continuously introducing air into the solution, dropwise adding 0.05mol/L NaOH solution into the solution in the reaction process, testing the pH value of the solution by using a pH meter, adjusting the pH value of the solution to 7.5, reacting for 4 hours, and oxidizing aldehyde group at one end of glutaraldehyde into carboxyl after the reaction is finished, namely one end of the reacted product is carboxyl and the other end is aldehyde group.

S2: filtering the mixed solution after the reaction in the step S1 is finished, standing the filtrate for 18h to obtain a standing mother solution, carrying out back extraction on the standing mother solution by using water, reducing the temperature to-5 ℃, and precipitating crystals from the solution after the back extraction;

s3: adding 85 parts by weight of polyvinyl alcohol into 130 parts by weight of deionized water, heating and stirring at the temperature of 65 ℃, adding 6 parts by weight of copper sulfate after the polyvinyl alcohol is dissolved, slowly adding 75 parts by weight of the crystal obtained in the step S2, carrying out esterification reaction, filtering after reacting for 4 hours, and removing the catalyst copper sulfate to obtain the modified polyvinyl alcohol. The copper sulfate is used as the catalyst, and is difficult to dissolve in reactants and products, so that the copper sulfate is easy to remove after the reaction is finished, the separation process is simplified, the separated copper sulfate can be repeatedly used, and the cost is saved.

A biodegradable high polymer packaging material is prepared from the following raw materials in parts by weight: 75 parts of modified polyvinyl alcohol; 12 parts of a stabilizer; 14 parts of a plasticizer; and 6 parts of an auxiliary agent. Wherein the stabilizer is zinc stearate; the plasticizer is prepared by mixing diisononyl phthalate and trioctyl citrate according to the weight ratio of 1: 1; the auxiliary agent is propyl gallate.

A preparation method of a biodegradable high polymer packaging material comprises the following steps: weighing the modified polyvinyl alcohol, the stabilizer, the plasticizer and the auxiliary agent according to the proportion, adding the weighed materials into a stirrer, and stirring for 20min at the stirring speed of 1000 r/min; adding the uniformly mixed raw materials into a double-screw extruder, extruding and granulating at the temperature of 120-160 ℃ to obtain the biodegradable polymer packaging material.

The application of biodegradable high molecular packing material includes packing commodity, chemical industry, building material, food additive and medicine.

Example 5

A biodegradable high-molecular packing material is prepared from modified polyvinyl alcohol, stabilizer, plasticizer and assistant;

the preparation method of the modified polyvinyl alcohol comprises the following steps:

s1: mixing 90 parts by weight of glutaraldehyde, 70 parts by weight of tributylamine as an extractant and 70 parts by weight of n-butanol as a diluent, and adding 8 parts by weight of Pd/SiO as a catalyst₂Heating and stirring, wherein the heating temperature is 60 ℃, continuously introducing air into the solution, dropwise adding 0.05mol/L NaOH solution into the solution in the reaction process, testing the pH value of the solution by using a pH meter, adjusting the pH value of the solution to 7.5, reacting for 4.5 hours, and oxidizing aldehyde group at one end of glutaraldehyde into carboxyl after the reaction is finished, namely, one end of the reacted product is carboxyl and the other end is aldehyde group.

S2: filtering the mixed solution after the reaction in the step S1 is finished, standing the filtrate for 18h to obtain a standing mother solution, carrying out back extraction on the standing mother solution by using water, reducing the temperature to-5 ℃, and precipitating crystals from the solution after the back extraction;

s3: adding 90 parts by weight of polyvinyl alcohol into 140 parts by weight of deionized water, heating and stirring at 65 ℃, adding 8 parts by weight of copper sulfate after the polyvinyl alcohol is dissolved, slowly adding 80 parts by weight of the crystal obtained in the step S2, carrying out esterification reaction, filtering after reacting for 4 hours, and removing a catalyst copper sulfate to obtain the modified polyvinyl alcohol. The copper sulfate is used as the catalyst, and is difficult to dissolve in reactants and products, so that the copper sulfate is easy to remove after the reaction is finished, the separation process is simplified, the separated copper sulfate can be repeatedly used, and the cost is saved.

A biodegradable high polymer packaging material is prepared from the following raw materials in parts by weight: 75 parts of modified polyvinyl alcohol; 12 parts of a stabilizer; 14 parts of a plasticizer; and 6 parts of an auxiliary agent. Wherein the stabilizer is zinc stearate; the plasticizer is prepared by mixing diisononyl phthalate and trioctyl citrate according to the weight ratio of 1: 1; the auxiliary agent is propyl gallate.

A preparation method of a biodegradable high polymer packaging material comprises the following steps: weighing the modified polyvinyl alcohol, the stabilizer, the plasticizer and the auxiliary agent according to the proportion, adding the weighed materials into a stirrer, and stirring for 20min at the stirring speed of 1000 r/min; adding the uniformly mixed raw materials into a double-screw extruder, extruding and granulating at the temperature of 120-160 ℃ to obtain the biodegradable polymer packaging material.

The application of biodegradable high molecular packing material includes packing commodity, chemical industry, building material, food additive and medicine.

Example 6

A biodegradable high-molecular packing material is prepared from modified polyvinyl alcohol, stabilizer, plasticizer and assistant;

the preparation method of the modified polyvinyl alcohol comprises the following steps:

s1: mixing 95 parts by weight of glutaraldehyde, 75 parts by weight of tributylamine as an extractant and 75 parts by weight of n-butanol as a diluent, and adding 8 parts by weight of Pd/SiO as a catalyst₂Heating and stirring at 55 ℃, continuously introducing air into the solution, dropwise adding 0.05mol/L NaOH solution into the solution in the reaction process, testing the pH of the solution by using a pH meter, adjusting the pH of the solution to 7.5, reacting for 4.5 hours, and oxidizing aldehyde group at one end of glutaraldehyde into carboxyl after the reaction is finished, namely one end of a product after the reaction is carboxyl, and the other end of the product after the reaction is carboxylThe end is aldehyde group.

S2: filtering the mixed solution after the reaction in the step S1 is finished, standing the filtrate for 20 hours to obtain a mother solution after standing, carrying out back extraction on the mother solution after standing by using water, reducing the temperature to-5 ℃, and precipitating crystals from the solution after the back extraction;

s3: adding 88 parts by weight of polyvinyl alcohol into 135 parts by weight of deionized water, heating and stirring at 65 ℃, adding 8 parts by weight of copper sulfate after the polyvinyl alcohol is dissolved, slowly adding 80 parts by weight of the crystal obtained in the step S2, carrying out esterification reaction, filtering after reacting for 4.5 hours, and removing the catalyst copper sulfate to obtain the modified polyvinyl alcohol. The copper sulfate is used as the catalyst, and is difficult to dissolve in reactants and products, so that the copper sulfate is easy to remove after the reaction is finished, the separation process is simplified, the separated copper sulfate can be repeatedly used, and the cost is saved.

A biodegradable high polymer packaging material is prepared from the following raw materials in parts by weight: 75 parts of modified polyvinyl alcohol; 12 parts of a stabilizer; 14 parts of a plasticizer; and 6 parts of an auxiliary agent. Wherein the stabilizer is diglycidyl terephthalate; the plasticizer is tributyl citrate; the auxiliary agent is butyl hydroxy anisol.

A preparation method of a biodegradable high polymer packaging material comprises the following steps: weighing the modified polyvinyl alcohol, the stabilizer, the plasticizer and the auxiliary agent according to the proportion, adding the weighed materials into a stirrer, and stirring for 20min at the stirring speed of 900 r/min; adding the uniformly mixed raw materials into a double-screw extruder, extruding and granulating at the temperature of 120-160 ℃ to obtain the biodegradable polymer packaging material.

The application of biodegradable high molecular packing material includes packing commodity, chemical industry, building material, food additive and medicine.

Comparative example 1

Compared with the example 4, the polyvinyl alcohol is not modified, the polyvinyl alcohol is directly used as the raw material, the glutaraldehyde is added, and the rest conditions are not changed.

A biodegradable high-molecular packing material is prepared from polyvinyl alcohol, glutaraldehyde, stabilizer, plasticizer and assistant;

a biodegradable high polymer packaging material is prepared from the following raw materials in parts by weight: 75 parts of polyvinyl alcohol; 75 parts of glutaraldehyde; 12 parts of a stabilizer; 14 parts of a plasticizer; and 6 parts of an auxiliary agent. Wherein the stabilizer is zinc stearate; the plasticizer is prepared by mixing diisononyl phthalate and trioctyl citrate according to the weight ratio of 1: 1; the auxiliary agent is propyl gallate.

A preparation method of a biodegradable high polymer packaging material comprises the following steps: weighing polyvinyl alcohol, glutaraldehyde, a stabilizer, a plasticizer and an auxiliary agent according to the proportion, adding the weighed materials into a stirrer, and stirring for 20min at the stirring speed of 1000 r/min; adding the uniformly mixed raw materials into a double-screw extruder, extruding and granulating at the temperature of 120-160 ℃ to obtain the biodegradable polymer packaging material.

The application of biodegradable high molecular packing material includes packing commodity, chemical industry, building material, food additive and medicine.

Comparative example 2

The same conditions as in example 4 were used except that polyvinyl alcohol was used as it is without modifying polyvinyl alcohol.

A biodegradable high-molecular packing material is prepared from polyvinyl alcohol, stabilizer, plasticizer and assistant;

a biodegradable high polymer packaging material is prepared from the following raw materials in parts by weight: 75 parts of polyvinyl alcohol; 12 parts of a stabilizer; 14 parts of a plasticizer; and 6 parts of an auxiliary agent. Wherein the stabilizer is zinc stearate; the plasticizer is prepared by mixing diisononyl phthalate and trioctyl citrate according to the weight ratio of 1: 1; the auxiliary agent is propyl gallate.

A preparation method of a biodegradable high polymer packaging material comprises the following steps: weighing polyvinyl alcohol, a stabilizer, a plasticizer and an auxiliary agent according to the proportion, adding the weighed materials into a stirrer, and stirring for 20min at the stirring speed of 1000 r/min; adding the uniformly mixed raw materials into a double-screw extruder, extruding and granulating at the temperature of 120-160 ℃ to obtain the biodegradable polymer packaging material.

The application of biodegradable high molecular packing material includes packing commodity, chemical industry, building material, food additive and medicine.

Comparative example 3

The comparative example is a commercially available degradable polymeric packaging material.

The mechanical properties of the examples and comparative examples are shown in table 1:

the test methods for the material properties were determined in accordance with the relevant regulations in the national standards.

TABLE 1

Sample (I)	Tensile strength/MPa	Elongation at break/%	Impact strength/MPa
				Example 1	49	46	19
Example 2	53	52	20
				Example 3	56	55	22
Example 4	62	60	25
				Example 5	52	54	21
Example 6	55	49	22
				Comparative example 1	34	38	13
Comparative example 2	35	36	12
				Comparative example 3	36	38	13

The bacteriostatic ratio of each example and comparative example is shown in table 2:

escherichia coli and Staphylococcus aureus were inoculated into 10mL Tryptone Soy Broth (TSB) in Erlenmeyer flasks, cultured at 37 ℃ for 12h, and then diluted to 1X 10, respectively⁶CFU/mL of bacterial suspension.

Samples of 10X 10mm in size were placed in 12-well plates, 1mL of each bacterial TSB suspension obtained above was added, and the suspension was incubated in an incubator at 37 ℃ for 48 hours. The sample was then subjected to ultrasonic cleaning in 10ml of 0.9% NaCl solution for 10min (200W, 40kHz), causing the bacteria adhering to the surface of the sample to disperse in the NaCl solution. Then, another 100 μ L of each bacterial suspension is taken for observing the growth condition of bacteria by a plate coating method and calculating the bacteriostasis rate.

TABLE 2

Sample (I)	Antibacterial rate of Escherichia coli	Staphylococcus aureus bacteriostasis rate
			Example 1	98.2％	97.8％
Example 2	99.3％	97.5％
			Example 3	99.7％	98.7％
Example 4	100％	100％
			Example 5	97.8％	99.6％
Example 6	97.5％	98.3％
			Comparative example 1	98.6％	97.9％
Comparative example 2	15.1％	20.2％
			Comparative example 3	2.5％	0％

The mass loss rates of the examples and comparative examples are shown in table 3:

the polymer packaging materials obtained in each example and comparative example, each group of which has a mass of 25g, were placed at room temperature, mixed with soil, and after standing for 3 months, the samples were cleaned, dried, weighed, and the mass loss rate was calculated.

TABLE 3

The data comparison in table 1 shows that the mechanical property of the biodegradable polymer packaging material prepared by the invention is superior to that of the commercially available degradable polymer material, and the data comparison in table 2 and table 3 shows that the biodegradable polymer packaging material prepared by the invention can effectively inhibit escherichia coli and staphylococcus aureus, and the degradation rate is obviously improved. It can be concluded that the biodegradable polymer packaging material prepared by the present invention can replace the current degradable polymer material.

In the present invention, the modification process of polyvinyl alcohol is as follows:

polyvinyl alcohol is automatically decomposed by bacteria and enzymes, but because of the existence of a large number of hydroxyl groups, polyvinyl alcohol forms a large number of intramolecular and intermolecular hydrogen bonds, and the melting temperature of polyvinyl alcohol is close to the decomposition temperature. In the invention, glutaraldehyde is mixed with tributylamine and n-butyl alcohol in the presence of a catalyst Pd/SiO₂In the presence of air, introducing air, and after reaction, oxidizing aldehyde group at one end of glutaraldehyde into carboxyl, wherein tributylamine is used as an extracting agent to ensure that glutaraldehyde with one end oxidized into carboxyl enters an organic phase, so that further oxidation is avoided, and the reaction is carried out towards a direction favorable for a product; the addition of the n-butyl alcohol is complexed with the tributylamine, so that the layering speed of the tributylamine is improved. The polyvinyl alcohol and the product are subjected to esterification reaction under the catalysis of copper sulfate to obtain the modified polyvinyl alcohol, so that the formation of a large amount of intra-molecular and intermolecular hydrogen bonds is avoided, the related performance of the polyvinyl alcohol is effectively improved, and meanwhile, the formed modified polyvinyl alcohol molecular chain contains active aldehyde groups, so that the synthesized biodegradable high-molecular packaging material has a good sterilization effect. As can be seen from the data analysis of tables 1-3, the biodegradable polymer packaging material prepared by the invention has excellent mechanical properties, can effectively inhibit Escherichia coli and Staphylococcus aureus, and further improves the degradation rate.

It is noted that, herein, relational terms such as first and second, and the like may be used solely to distinguish one entity or action from another entity or action without necessarily requiring or implying any actual such relationship or order between such entities or actions. Also, the terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus.

Although embodiments of the present application have been shown and described, it will be appreciated by those skilled in the art that changes, modifications, substitutions and alterations can be made in these embodiments without departing from the principles and spirit of the application, the scope of which is defined in the appended claims and their equivalents.