CN108624020A - Seawater degradation material with adjustable use period and degradation period and preparation method thereof - Google Patents

Abstract

The invention discloses a seawater degradation material with adjustable service period and degradation period and a preparation method thereof. The seawater degradable material with adjustable service period and degradation period is made of the following raw materials in parts by weight: 8-90 parts of thermoplastically modified polyvinyl alcohol; 8-90 parts of polyester; 0-2 parts of compatibilizer . The preparation method of the seawater degradable material comprises the following steps: 1) thermoplastic modification of polyvinyl alcohol: mixing polyvinyl alcohol and a plasticizer, sealing and plasticizing, extruding and granulating; 2) making the seawater degradable material Preparation: The thermoplastically modified polyvinyl alcohol, polyester and compatibilizer are mixed in proportion, extruded and granulated, and injection molded to obtain a seawater degradable material with adjustable service life and degradation cycle. The seawater degradable material of the present invention is a PVA composite material that can be processed through melt blending, has a simple and controllable process and low energy consumption, and effectively overcomes the problems of high cost and low efficiency of the traditional process based on PVA aqueous solution.

Description

A seawater degradable material with adjustable use period and degradation period and its preparation method

technical field

The invention relates to the technical field of seawater purification. More specifically, it relates to a seawater degradable material with adjustable use period and degradation period and a preparation method thereof.

Background technique

In recent years, the world has used no less than 240 million tons of plastics and their products every year. It is conservatively estimated that 4.8-12.7 million tons of plastic waste is directly discarded or enters the ocean from land through rivers and wind, and is transported by ocean currents. Widely present in the whole marine ecosystem. These plastic wastes are affected by solar radiation (such as photodegradation, embrittlement), weathering, wave mechanical force, and biota, and finally form tiny plastic fragments or particles, which can be defined as "microplastics" when the diameter is less than 5mm. . From large-volume plastic products to microplastics, they all exist in solid form and are difficult to degrade plastic waste, which has caused serious damage to the marine ecological environment. Therefore, it is possible to develop products that can "disappear" in the seawater environment and can be quickly degraded afterwards. Plastic is of great significance to solving the problem of marine plastic pollution.

In order to make the material "disappear" as soon as possible after being discarded into seawater, many water-soluble polymer materials fully meet this condition. However, in order not to pollute the marine environment, the material must be able to degrade and produce small molecules that are not harmful to the environment. Based on the above considerations, polyvinyl alcohol (PVA) can meet the requirements. It not only has adjustable water solubility with changes in the degree of polymerization or alcoholysis, can be synthesized through non-petrochemical routes, and can also be used in wet water such as sewage sludge and river water. Under the conditions of the presence of bacteria in the environment, complete biodegradation is carried out. Therefore, in the context of the depletion of petroleum resources and the increasing plastic pollution of land and oceans, using PVA as the main component of seawater degradation materials has great application prospects. However, due to the strong hydrogen bond characteristics of PVA's polyhydric groups, its decomposition temperature (200-250°C) is close to its melting point (230°C), making thermoplastic processing difficult. Therefore, the processing of PVA is almost always based on its aqueous solution.

In order to achieve low-cost and high-efficiency melt processing of PVA, it is necessary to add plasticizers such as polyols and carboxylic acids to form hydrogen bond complexes with PVA to inhibit the crystallization of PVA, lower the melting point, and widen the processing range to improve PVA. Purpose of thermoplastic processing use cycle and degradation cycle. For example, CN 106589852A discloses a water-degradable material with adjustable degradation cycle, but it is not advisable to use polyvinyl alcohol as a hydrolysis accelerator to melt and extrude directly with aliphatic polyester and auxiliary agents, because it is not thermoplastically modified PVA is not only difficult to process thermoplastically, the product is easy to decompose, the use of mechanical properties is lost, and it does not have good water solubility. It is also worth noting that although PVA can be completely biodegraded, its degradation has higher requirements on the degradation environment. Soil and river water are very few, and it is basically certain that although the water solubility of PVA can make it dissolve in seawater and thus promote biodegradation, the degradation rate of PVA is relatively slow. Simultaneously, PVA shows the defect of poor water resistance when used as a product material. How to overcome the poor water resistance of PVA while ensuring the water solubility of PVA is a challenging technical problem.

Therefore, the present invention provides a seawater degradable material with adjustable use period and degradation period and a preparation method thereof, at least solving one of the above-mentioned problems.

Contents of the invention

An object of the present invention is to provide a seawater degradable material with adjustable service period and degradation period.

Another object of the present invention is to provide a method for preparing a seawater degradable material with adjustable use period and degradation period.

In order to achieve the above-mentioned first object, the present invention adopts the following technical solutions:

A seawater degradable material with adjustable use period and degradation period, made of the following raw materials in parts by weight:

8-90 parts of polyvinyl alcohol after thermoplastic modification;

8-90 parts of polyester;

0-2 parts of compatibilizer.

Preferably, the thermoplastically modified polyvinyl alcohol is prepared by mixing polyvinyl alcohol and a plasticizer, sealing and plasticizing, and extrusion granulation; wherein the mass ratio of polyvinyl alcohol and plasticizer is 80: 20-90:10.

Preferably, the plasticizing temperature is room temperature-60°C; further, in some specific embodiments of the present invention, for example, the plasticizing temperature is room temperature-30°C, room temperature-40°C, room temperature- 50°C, 30-40°C, 30-50°C, 30-60°C, 40-50°C, 40-60°C, 50-60°C, etc.

Preferably, the plasticizing time is 3-6h; further, in some specific embodiments of the present invention, for example, the plasticizing time is 3-4h, 3-5h, 4-5h, 4h -6h, 5-6h, etc.

Preferably, the extrusion granulation temperature is 160-200°C; further, in some specific embodiments of the present invention, for example, the extrusion granulation temperature is 160-170°C, 170-200°C ℃ and so on.

Preferably, the degree of polymerization of the polyvinyl alcohol is 300-2600, and the degree of alcoholysis of the polyvinyl alcohol is 88%-99%.

Preferably, the model of the polyvinyl alcohol is 0388, 0488, 0499, 0588, 0599, 1099, 1399, 1599, 1788, 1792, 1795, 1797, 1799, 2088, 2099, 2488, 2499, 2699.

Preferably, the plasticizer is selected from one or more of sorbitol, 1,4-butanediol, glycerin, ethylene glycol, and citric acid.

Preferably, the polyester is a polyester whose standard bar loses more than 30wt% weight within one year in seawater.

Preferably, the polyester is polycaprolactone and/or polyhydroxyalkanoate.

Preferably, the compatibilizer is selected from one or more of ADR-4380, ADR-4370S, KH-560, KH-570, MDI and HDI.

Preferably, the seawater degradation material is an alloy material or a material with a skin-core structure.

Preferably, in the seawater degradable material of the skin-core structure, the material of the skin layer is polyester, and the material of the core layer is thermoplastically modified polyvinyl alcohol.

In order to achieve the above-mentioned second purpose, the present invention adopts the following technical solutions:

A preparation method of the above-mentioned seawater degradable material with adjustable use period and degradation period, comprising the steps of:

1) Thermoplastic modification of polyvinyl alcohol:

Mix polyvinyl alcohol and plasticizer, seal and plasticize, extrude and granulate;

2) Preparation of seawater degradable material: mixing thermoplastically modified polyvinyl alcohol, polyester and compatibilizer in proportion, extrusion granulation, injection molding to obtain seawater degradable material with adjustable service life and degradation period.

Preferably, the plasticizing temperature in step 1) is room temperature-60°C; further, in some specific embodiments of the present invention, for example, the plasticizing temperature in step 1) is room temperature-30°C , Room temperature -40°C, room temperature -50°C, 30-40°C, 30-50°C, 30-60°C, 40-50°C, 40-60°C, 50-60°C, etc.

Preferably, the plasticizing time in step 1) is 3-6h; further, in some specific embodiments of the present invention, for example, the plasticizing time in step 1) is 3-4h, 3h -5h, 4-5h, 4-6h, 5-6h, etc.

Preferably, the extrusion granulation temperature in step 1) is 160-200°C; further, in some specific embodiments of the present invention, for example, the extrusion granulation temperature in step 1) is 160-170°C, 170-200°C, etc.

Preferably, the extrusion granulation temperature in step 2) is 160-200°C; further, in some specific embodiments of the present invention, for example, the extrusion granulation temperature in step 2) is 160-170°C, 170-200°C, etc.

Preferably, the injection molding temperature in step 2) is 170-210°C; further, in some specific embodiments of the present invention, for example, the injection molding temperature in step 2) is 170-180°C, 170°C -190°C, 180-190°C, 180-210°C, 190-210°C, etc.

The beneficial effects of the present invention are as follows:

(1) The raw materials of the seawater degradable material of the present invention can be synthesized through non-petrochemical routes, and all belong to completely biodegradable materials, which meet the requirements of sustainable development.

(2) The seawater degradable material of the present invention is a PVA composite material that can be processed by melt blending. The process is simple and controllable, and the energy consumption is low, which effectively overcomes the problems of high cost and low efficiency of the traditional process based on PVA aqueous solution.

(3) The seawater degradable material of the present invention can be an alloy material structure with good compatibility, and can also be a skin-core structure, wherein the skin layer component is polyester, and the core layer component is thermoplastically modified polyvinyl alcohol, These structures inhibit the hygroscopicity of PVA during use to a certain extent, greatly prolonging the service life of the product.

(4) By changing the PVA type or the ratio of the PVA/polyester composite material, the seawater degradable material of the present invention has an adjustable service period and seawater degradation period.

(5) The seawater degradable material of the present invention can meet the actual needs in aspects such as military or civilian ships and some marine supplies.

Detailed ways

In order to illustrate the present invention more clearly, the present invention will be further described below in conjunction with preferred embodiments. Those skilled in the art should understand that the content specifically described below is illustrative rather than restrictive, and should not limit the protection scope of the present invention.

The invention provides a seawater degradable material with adjustable service period and degradation period, which is made of the following raw materials in parts by weight: 8-90 parts of thermoplastically modified polyvinyl alcohol; 8-90 parts of polyester; compatible Dose 0-2 parts. When the present invention prepares seawater degradable materials, the use of thermoplastically modified polyvinyl alcohol not only improves the water solubility, thermal stability and mechanical properties of PVA, but also prepares PVA composites through thermoplastic processing with simple and controllable technology and low energy consumption. Materials, the obtained seawater degradable materials have a service life of not less than 2 years at room temperature, and the waste will be significantly degraded after entering seawater.

Among them, the role of thermoplastically modified polyvinyl alcohol is to promote the water absorption of seawater degradation materials; the role of polyester is to promote the biodegradability of seawater degradation materials and inhibit the water absorption of seawater degradation materials during use; the compatibilizer The role is to enhance the interaction between polyvinyl alcohol and polyester through coupling.

A possible realization of thermoplastic modification is to add polyvinyl alcohol and plasticizer in a mass ratio of 80:20-90:10 to a high-speed mixer for multiple times until fully mixed to obtain a premix, and then The premix is sealed and placed at room temperature -60°C for plasticization for 3-6 hours, and then extruded and granulated in a twin-screw extruder at 160-200°C to obtain thermoplastically modified polyvinyl alcohol. Among them, the role of the plasticizer is to plasticize the PVA.

Optionally, the degree of polymerization of the polyvinyl alcohol is 300-2600, and the degree of alcoholysis of the polyvinyl alcohol is 88%-99%. The polyvinyl alcohol in the range of the degree of polymerization and the degree of alcoholysis is common commercially available polyvinyl alcohol, the raw material is easy to obtain, the property is stable, and the water solubility becomes worse with the increase of the degree of polymerization or the degree of alcoholysis.

Further, the plasticizer is preferably selected from one or more of sorbitol, 1,4-butanediol, glycerin, ethylene glycol, and citric acid; the above-mentioned plasticizers are common polyols and carboxylic acids Such substances are not only cheap, but also have a remarkable effect on the thermoplastic modification of PVA.

Optionally, in order to obtain a polyester that can be degraded in seawater and degrades quickly, the polyester is preferably a polyester whose weight loss exceeds 30wt% in seawater for a standard strip within one year.

Further, the polyester is polycaprolactone and/or polyhydroxyalkanoate, and the polyester not only has excellent seawater degradation performance, but also can be synthesized by microbial fermentation, meeting the requirements of sustainable development.

As a preferred scheme, the compatibilizer is selected from one or more of ADR-4380, ADR-4370S, KH-560, KH-570, MDI and HDI; the compatibilizer is a common commercial product The coupling agent can significantly enhance the interaction between PVA and polyester.

In addition, the seawater degradable material of the present invention can be an alloy material structure with good compatibility, or a skin-core structure, wherein the skin layer component is polyester, and the core layer component is thermoplastically modified polyvinyl alcohol. The structure suppresses the problem of water absorption to a certain extent, which is conducive to longer-term use. The structure of the alloy material is through the pulling effect of the polyester on the PVA, and this effect can be enhanced by adding a compatibilizer, thereby suppressing the water absorption of the PVA; Mechanical isolation, thereby inhibiting the water absorption of the core PVA.

In addition, the second aspect of the present invention also provides a method for preparing the above-mentioned seawater degradable material with adjustable use period and degradation period, comprising the following steps:

1) Thermoplastic modification of polyvinyl alcohol:

Mix polyvinyl alcohol and plasticizer, seal and plasticize, extrude and granulate;

2) Preparation of seawater degradable material: mixing thermoplastically modified polyvinyl alcohol, polyester and compatibilizer in proportion, extrusion granulation, injection molding to obtain seawater degradable material with adjustable service life and degradation period.

Hereinafter, each step in the synthesis method will be described in detail.

A possible implementation in step 1) is to add polyvinyl alcohol and plasticizer in a high-speed mixer at a mass ratio of 80:20-90:10 and stir several times until fully mixed to obtain a premix, and then The premix is sealed and placed at room temperature -60°C for plasticization for 3-6 hours, and then extruded and granulated in a twin-screw extruder at 160-200°C to obtain thermoplastically modified polyvinyl alcohol.

A possible implementation in step 2) is to pre-mix the thermoplastically modified polyvinyl alcohol, polyester and compatibilizer to obtain a mixture, and then extrude and granulate the mixture through twin-screw at 160-200°C, 170 The seawater degradable material with adjustable service period and degradation period was obtained by injection molding at -210°C.

In the present invention, the preparation methods are conventional methods unless otherwise specified, and the raw materials used can be obtained from public commercial sources or prepared according to the prior art unless otherwise specified.

Example 1

A seawater degradable material with adjustable use period and degradation period, made of the following raw materials in parts by weight:

0388 polyvinyl alcohol after thermoplastic modification: 8 parts;

Polycaprolactone: 90 parts;

ADR-4380: 2 servings.

The preparation of the above-mentioned seawater degradation material comprises the following steps:

1) Thermoplastic modification of polyvinyl alcohol: add 0388 polyvinyl alcohol and sorbitol in a mass ratio of 80:20 to a high-speed mixer and stir for several times, stirring for 1 to 2 minutes each time until fully mixed and uniform, to obtain a premixed Then seal the premixed material and place it at room temperature for plasticization for 6 hours. After taking it out, extrude and granulate it in a twin-screw extruder at an extrusion temperature of 160°C to obtain thermoplastically modified polyvinyl alcohol;

2) Preparation of seawater degradable material: 8 parts of thermoplastically modified polyvinyl alcohol, 90 parts of polycaprolactone and 2 parts of ADR-4380 prepared in step 1) are pre-mixed to obtain a mixture, and then passed through a twin-screw 160 Extrude and granulate under the condition of 170°C, and inject the test sample under the condition of 170°C to obtain the seawater degradable material with alloy material structure. The seawater degradation properties and service mechanical properties of the prepared seawater degradable materials are shown in Table 1 and Table 2, respectively.

Example 2

A seawater degradable material with adjustable use period and degradation period, made of the following raw materials in parts by weight:

0388 polyvinyl alcohol after thermoplastic modification: 90 parts;

Polyhydroxyalkanoate: 10 parts.

The preparation of the above-mentioned seawater degradation material comprises the following steps:

1) Thermoplastic modification of polyvinyl alcohol: add 0388 polyvinyl alcohol and 1,4-butanediol in a mass ratio of 90:10, and then add them to a high-speed mixer for multiple times of stirring, stirring for 1-2 minutes each time, until fully mixed and uniform , to prepare the premix, then seal the premix and place it in a 60°C oven for plasticization for 3 hours, take it out and extrude and granulate it in a twin-screw extruder at an extrusion temperature of 160°C to obtain thermoplastically modified polyvinyl alcohol;

2) Preparation of seawater degradable material: premix 90 parts of thermoplastically modified polyvinyl alcohol and 10 parts of polyhydroxyalkanoate obtained in step 1) to obtain a mixture, and then extrude it through a twin-screw at 160° C. After granulation, test specimens were obtained by injection molding at 170°C, and a seawater-degradable material with a skin-core structure was obtained. The seawater degradation properties and service mechanical properties of the prepared seawater degradable materials are shown in Table 1 and Table 2, respectively.

Example 3

A seawater degradable material with adjustable use period and degradation period, made of the following raw materials in parts by weight:

0588 polyvinyl alcohol after thermoplastic modification: 20 parts;

Polyhydroxyalkanoate: 79 parts;

ADR-4370s: 1 serving.

The preparation of the above-mentioned seawater degradation material comprises the following steps:

1) Thermoplastic modification of polyvinyl alcohol: add 0588 polyvinyl alcohol and glycerin in a mass ratio of 85:15 to a high-speed mixer for multiple times of stirring, stirring for 1-2 minutes each time, until fully mixed to obtain a premix , and then seal the premix and place it in an oven at 30°C for plasticization for 5 hours. After taking it out, extrude and granulate it in a twin-screw extruder at an extrusion temperature of 160°C to obtain thermoplastically modified polyvinyl alcohol;

2) Preparation of seawater degradable material: 20 parts of thermoplastically modified polyvinyl alcohol, 79 parts of polyhydroxyalkanoate and 1 part of ADR-4370s obtained in step 1) are pre-mixed to obtain a mixture, and then passed through double The screw was extruded and granulated at 160°C, and the test sample was obtained by injection molding at 170°C to obtain a seawater-degradable material with an alloy material structure. The seawater degradation properties and service mechanical properties of the prepared seawater degradable materials are shown in Table 1 and Table 2, respectively.

Example 4

A seawater degradable material with adjustable use period and degradation period, made of the following raw materials in parts by weight:

0588 polyvinyl alcohol after thermoplastic modification: 80 parts;

Polycaprolactone: 20 parts.

The preparation of the above-mentioned seawater degradation material comprises the following steps:

1) Thermoplastic modification of polyvinyl alcohol: Add 0588 polyvinyl alcohol and ethylene glycol in a mass ratio of 80:20 to a high-speed mixer for multiple times of stirring, stirring for 1 to 2 minutes each time, until fully mixed and uniform, to prepare the pre- Mix the materials, then seal the premix and place it in an oven at 40°C for plasticization for 4 hours, take it out and extrude and granulate it in a twin-screw extruder at an extrusion temperature of 160°C to obtain thermoplastically modified polyvinyl alcohol;

2) Preparation of seawater degradable material: 80 parts of thermoplastically modified polyvinyl alcohol and 20 parts of polycaprolactone prepared in step 1) are pre-mixed to obtain a mixture, and then extruded by twin-screw at 160°C Pelletizing, injection molding at 170°C to obtain test specimens, and a seawater-degradable material with a skin-core structure. The seawater degradation properties and service mechanical properties of the prepared seawater degradable materials are shown in Table 1 and Table 2, respectively.

Example 5

A seawater degradable material with adjustable use period and degradation period, made of the following raw materials in parts by weight:

0599 polyvinyl alcohol after thermoplastic modification: 30 parts;

Polyhydroxyalkanoate: 68.5 parts;

KH560: 1.5 parts.

The preparation of the above-mentioned seawater degradation material comprises the following steps:

1) Thermoplastic modification of polyvinyl alcohol: Add 0599 polyvinyl alcohol and citric acid in a mass ratio of 90:10 to a high-speed mixer for multiple times of stirring, stirring for 1 to 2 minutes each time, until fully mixed and uniform to obtain a premixed The premixed material was then sealed and placed in an oven at 50°C for plasticization for 3 hours. After taking it out, it was extruded and granulated in a twin-screw extruder at an extrusion temperature of 170°C to obtain thermoplastically modified polyvinyl alcohol;

2) Preparation of seawater degradable material: 30 parts of thermoplastically modified polyvinyl alcohol, 68.5 parts of polyhydroxyalkanoate and 1.5 parts of KH560 obtained in step 1) are pre-mixed to obtain a mixture, and then passed through a twin-screw 170 Extrude and granulate under the condition of ℃, injection molding under the condition of 200℃ to obtain the test sample, and obtain the seawater degradable material with alloy material structure. The seawater degradation properties and service mechanical properties of the prepared seawater degradable materials are shown in Table 1 and Table 2, respectively.

Example 6

A seawater degradable material with adjustable use period and degradation period, made of the following raw materials in parts by weight:

0599 polyvinyl alcohol after thermoplastic modification: 70 parts;

Polycaprolactone: 30 parts.

The preparation of the above-mentioned seawater degradation material comprises the following steps:

1) Thermoplastic modification of polyvinyl alcohol: Add 0599 polyvinyl alcohol and sorbitol in a mass ratio of 80:20 to a high-speed mixer and stir for several times, stirring for 1 to 2 minutes each time until fully mixed and uniform, to obtain a premixed Then seal the premixed material and place it at room temperature for plasticization for 6 hours. After taking it out, extrude and granulate it in a twin-screw extruder at an extrusion temperature of 170°C to obtain thermoplastically modified polyvinyl alcohol;

2) Preparation of seawater degradable material: pre-mix 70 parts of thermoplastically modified polyvinyl alcohol and 30 parts of polycaprolactone obtained in step 1) to obtain a mixture, and then extrude through twin-screw at 170°C Pelletizing, injection molding at 200°C to obtain test specimens, to obtain a seawater-degradable material with a skin-core structure. The seawater degradation properties and service mechanical properties of the prepared seawater degradable materials are shown in Table 1 and Table 2, respectively.

Example 7

A seawater degradable material with adjustable use period and degradation period, made of the following raw materials in parts by weight:

1788 polyvinyl alcohol after thermoplastic modification: 40 parts;

Polycaprolactone: 59.5 parts;

MDI: 0.5 parts.

The preparation of the above-mentioned seawater degradation material comprises the following steps:

1) Thermoplastic modification of polyvinyl alcohol: add 1788 polyvinyl alcohol and 1,4-butanediol in a mass ratio of 90:10 to a high-speed mixer and stir for several times, stirring for 1 to 2 minutes each time until fully mixed and uniform , to prepare the premix, then seal the premix and place it in an oven at 60°C for plasticization for 3 hours, take it out, extrude and granulate it in a twin-screw extruder at an extrusion temperature of 170°C, and obtain thermoplastically modified polyvinyl alcohol;

2) Preparation of seawater degradable material: 40 parts of thermoplastically modified polyvinyl alcohol, 59.5 parts of polycaprolactone and 0.5 part of MDI prepared in step 1) are pre-mixed to obtain a mixture, and then passed through a twin-screw at 170 ° C Extrude and granulate under the condition of 180 ℃ to obtain the test sample, and obtain the seawater degradable material of the alloy material structure. The seawater degradation properties and service mechanical properties of the prepared seawater degradable materials are shown in Table 1 and Table 2, respectively.

Example 8

A seawater degradable material with adjustable use period and degradation period, made of the following raw materials in parts by weight:

1788 polyvinyl alcohol after thermoplastic modification: 60 parts;

Polyhydroxyalkanoate: 40 parts.

The preparation of the above-mentioned seawater degradation material comprises the following steps:

1) Thermoplastic modification of polyvinyl alcohol: Add 1788 polyvinyl alcohol and glycerin in a mass ratio of 85:15 to a high-speed mixer for multiple times of stirring, stirring for 1 to 2 minutes each time, until fully mixed to obtain a premix , then seal the premix and place it in an oven at 30°C for plasticization for 5 hours, take it out and extrude and granulate it in a twin-screw extruder at an extrusion temperature of 170°C to obtain thermoplastically modified polyvinyl alcohol;

2) Preparation of seawater degradable material: pre-mix 60 parts of thermoplastically modified polyvinyl alcohol and 40 parts of polyhydroxyalkanoate obtained in step 1) to obtain a mixture, and then extrude it through a twin-screw at 170°C. After granulation, test specimens were obtained by injection molding at 190°C, and a seawater-degradable material with a skin-core structure was obtained. The seawater degradation properties and service mechanical properties of the prepared seawater degradable materials are shown in Table 1 and Table 2, respectively.

Example 9

A seawater degradable material with adjustable use period and degradation period, made of the following raw materials in parts by weight:

1792 polyvinyl alcohol after thermoplastic modification: 90 parts;

Polyhydroxyalkanoate: 8 parts;

KH-570: 2 servings.

The preparation of the above-mentioned seawater degradation material comprises the following steps:

1) Thermoplastic modification of polyvinyl alcohol: add 1792 polyvinyl alcohol and ethylene glycol in a mass ratio of 80:20 to a high-speed mixer and stir for several times, stirring for 1 to 2 minutes each time, until fully mixed and uniform, to prepare the pre- Mix the materials, then seal the premix and place it in an oven at 40°C for plasticization for 4 hours, take it out and extrude and granulate it in a twin-screw extruder at an extrusion temperature of 170°C to obtain thermoplastically modified polyvinyl alcohol;

2) Preparation of seawater degradable material: 90 parts of thermoplastically modified polyvinyl alcohol, 8 parts of polyhydroxyalkanoate and 2 parts of KH-570 prepared in step 1) are pre-mixed to obtain a mixture, and then passed through double The screw was extruded and granulated at 170°C, and the test sample was obtained by injection molding at 190°C to obtain a seawater-degradable material with an alloy material structure. The seawater degradation properties and service mechanical properties of the prepared seawater degradable materials are shown in Table 1 and Table 2, respectively.

Example 10

A seawater degradable material with adjustable use period and degradation period, made of the following raw materials in parts by weight:

2699 polyvinyl alcohol after thermoplastic modification: 50 parts;

Polycaprolactone: 48 parts;

HDI: 2 servings.

The preparation of the above-mentioned seawater degradation material comprises the following steps:

1) Thermoplastic modification of polyvinyl alcohol: Add 2699 polyvinyl alcohol and ethylene glycol in a mass ratio of 80:20 to a high-speed mixer for multiple times of stirring, stirring for 1 to 2 minutes each time until fully mixed and uniform, to prepare the pre- Mix the materials, then seal the premix and place it in an oven at 40°C for plasticization for 4 hours, take it out and extrude and granulate it in a twin-screw extruder at an extrusion temperature of 200°C to obtain thermoplastically modified polyvinyl alcohol;

2) Preparation of seawater degradable material: 50 parts of thermoplastically modified polyvinyl alcohol, 48 parts of polycaprolactone and 2 parts of HDI prepared in step 1) are pre-mixed to obtain a mixture, and then passed through a twin-screw at 200 ° C Extrude and granulate under the condition of 210 ℃ to obtain the test sample, and obtain the seawater degradable material of the alloy material structure. The seawater degradation properties and service mechanical properties of the prepared seawater degradable materials are shown in Table 1 and Table 2, respectively.

Table 1 Seawater degradation performance of seawater degradable materials

Example Weight loss after 30 days of degradation (wt%) Weight loss after 60 days of degradation (wt%) 1 7 15 2 95 98 3 11 twenty three 4 69 89 5 6 13 6 15 31 7 9 19 8 31 59 9 twenty one 49 10 4 9

Table 2 Mechanical properties of seawater degradable materials

Comparative example 1

A seawater degradation material is made of the following raw materials in parts by weight:

1788 polyvinyl alcohol: 40 parts;

Polycaprolactone: 59.5 parts;

MDI: 0.5 parts.

The preparation of the above-mentioned seawater degradation material comprises the following steps:

Pre-mix 40 parts of polyvinyl alcohol, 59.5 parts of polycaprolactone and 0.5 parts of MDI to obtain a mixture, then extrude and granulate through twin-screw at 220°C, and inject test samples at 230°C to obtain seawater degradable material.

The results show that: compared with Example 7, the polyvinyl alcohol in this comparative example has not been thermoplastically modified in advance, so the obtained seawater degradable material can only be melted and extruded at a relatively high temperature of 220°C, and significant heat loss occurs. Degradation, loss of mechanical properties, poor water solubility, 3wt% weight loss after 30 days of seawater degradation, 7wt% weight loss after 60 days, far lower than 9wt% and 19wt% of Example 7 respectively.

Comparative example 2

A seawater degradation material is made of the following raw materials in parts by weight:

0588 polyvinyl alcohol after thermoplastic modification: 80 parts;

Polylactic acid: 20 parts.

The preparation of the above-mentioned seawater degradation material comprises the following steps:

1) Thermoplastic modification of polyvinyl alcohol: Add 0588 polyvinyl alcohol and ethylene glycol in a mass ratio of 80:20 to a high-speed mixer for multiple times of stirring, stirring for 1 to 2 minutes each time, until fully mixed and uniform, to prepare the pre- Mix the materials, then seal the premix and place it in an oven at 40°C for plasticization for 4 hours, take it out and extrude and granulate it in a twin-screw extruder at an extrusion temperature of 160°C to obtain thermoplastically modified polyvinyl alcohol;

2) Preparation of seawater degradable material: pre-mix 80 parts of thermoplastically modified polyvinyl alcohol and 20 parts of polylactic acid prepared in step 1) to obtain a mixture, and then extrude and granulate through twin-screw at 170°C , The test sample was obtained by injection molding at 180°C, and the seawater degradable material was prepared.

The results show that: the seawater degradable material prepared in this comparative example loses 29wt% after 30 days of seawater degradation, and loses 43wt% after 60 days, which are far lower than 69wt% and 89wt% of Example 4, respectively. Therefore, the use of polyesters such as polylactic acid and polyvinyl alcohol that degrade slowly or even not in seawater to form a composite material is not conducive to promoting the seawater degradation performance of the composite material.

Apparently, the above-mentioned embodiments of the present invention are only examples for clearly illustrating the present invention, and are not intended to limit the implementation of the present invention. Those of ordinary skill in the art can also make It is impossible to exhaustively list all the implementation modes here, and any obvious changes or changes derived from the technical solutions of the present invention are still within the scope of protection of the present invention.

Claims (10)

1. A seawater degradable material with adjustable use period and degradation period, characterized in that it is made of the following raw materials in parts by weight: 8-90 parts of polyvinyl alcohol after thermoplastic modification; 8-90 parts of polyester; 0-2 parts of compatibilizer. 2. The seawater degradable material with adjustable service life and degradation cycle according to claim 1, characterized in that the thermoplastically modified polyvinyl alcohol is sealed and plasticized by mixing polyvinyl alcohol and a plasticizer , prepared by extrusion granulation; wherein, the mass ratio of polyvinyl alcohol and plasticizer is 80:20-90:10. 3. The seawater degradable material with adjustable service period and degradation period according to claim 2, characterized in that, the temperature of the plasticization is room temperature-60°C; the time of the plasticization is 3-6h; The temperature for extrusion granulation is 160-200°C. 4. The seawater degradable material with adjustable service life and degradation cycle according to claim 1, characterized in that, the degree of polymerization of the polyvinyl alcohol is 300-2600, and the degree of alcoholysis of the polyvinyl alcohol is 88% -99%. 5. The seawater degradable material with adjustable service life and degradation period according to claim 2, wherein the plasticizer is selected from the group consisting of sorbitol, 1,4-butanediol, glycerin, ethylene glycol, lemon one or more of acids. 6. The seawater degradable material with adjustable service period and degradation period according to claim 1, characterized in that, the polyester is a polyester whose standard spline loses more than 30wt% of weight in seawater within one year. 7. The seawater degradable material with adjustable service life and degradation cycle according to claim 1, characterized in that the polyester is polycaprolactone and/or polyhydroxyalkanoate. 8. The seawater degradable material with adjustable service life and degradation cycle according to claim 1, wherein the compatibilizer is selected from ADR-4380, ADR-4370S, KH-560, KH-570, MDI and One or more of HDI. 9. The seawater degradable material with adjustable service life and degradation period according to claim 2, characterized in that, the seawater degradable material is an alloy material or a material with a skin-core structure; in the seawater degradable material with a skin-core structure , the material of the skin layer is polyester, and the material of the core layer is thermoplastically modified polyvinyl alcohol. 10. A method for preparing a seawater degradable material with adjustable service life and degradation cycle as claimed in any one of claims 1 to 9, characterized in that it comprises the following steps: 1) Thermoplastic modification of polyvinyl alcohol: Mix polyvinyl alcohol and plasticizer, seal and plasticize, extrude and granulate; 2) Preparation of seawater degradable materials: The thermoplastically modified polyvinyl alcohol, polyester and compatibilizer are mixed in proportion, extruded and granulated, and injection molded to obtain a seawater degradable material with adjustable service life and degradation cycle.