阅读说明：本技术 高分子材料降解性能的评价方法 (Method for evaluating degradation performance of high polymer material ) 是由 王格侠 季君晖 卢波 李飞 甄志超 于 2020-05-15 设计创作，主要内容包括：本发明公开了一种高分子材料降解性能的评价方法,其包括如下步骤：(1)提供待评价的高分子材料样品,测量高分子材料样品的初始分子量和初始重量；(2)将高分子材料样品置于预设环境中进行降解,持续预定时长；(3)检测高分子材料样品降解后的分子量变化、重量变化以及降解过程中的总有机碳含量变化；(4)按照指定顺序判断分子量变化、重量变化以及降解过程中的总有机碳含量变化是否大于各自的预设阈值,并基于判断结果给出降解性能评价结论。本发明的评价方法能够以最简捷的步骤区分生物降解与非酶水解、溶解等,而且评价得到的降解性能与实际测试环境相关联。(The invention discloses a method for evaluating the degradation performance of a high polymer material, which comprises the following steps: (1) providing a high molecular material sample to be evaluated, and measuring the initial molecular weight and the initial weight of the high molecular material sample; (2) putting a high polymer material sample in a preset environment for degradation for a preset time; (3) detecting the molecular weight change and the weight change of the high molecular material sample after degradation and the total organic carbon content change in the degradation process; (4) and judging whether the molecular weight change, the weight change and the total organic carbon content change in the degradation process are larger than respective preset thresholds according to a specified sequence, and giving a degradation performance evaluation conclusion based on the judgment result. The evaluation method can distinguish biodegradation from non-enzymatic hydrolysis, dissolution and the like by the simplest steps, and the degradation performance obtained by evaluation is associated with the actual test environment.)

1. The method for evaluating the degradation performance of the high polymer material comprises the following steps:

(1) providing a high molecular material sample to be evaluated, and measuring the initial molecular weight and the initial weight of the high molecular material sample;

(2) putting the high polymer material sample in a preset environment for degradation for a preset time;

(3) detecting the molecular weight change and the weight change of the high molecular material sample after degradation and the total organic carbon content change in the degradation process;

(4) and judging whether the molecular weight change, the weight change and the total organic carbon content change in the degradation process are larger than respective preset thresholds according to a specified sequence, and giving a degradation performance evaluation conclusion based on the judgment result.

2. The method of claim 1, wherein the predetermined order comprises:

firstly, judging whether the molecular weight change is larger than a preset threshold value;

and selecting and then judging whether the change of the total organic carbon content is larger than a preset threshold value or not according to the judgment result of the change of the molecular weight, or then judging whether the change of the weight is larger than the preset threshold value or not.

3. The method according to claim 2, wherein if the determination is made whether the change in the total organic carbon content is greater than the predetermined threshold, an evaluation result is provided according to the determination result.

4. The method according to claim 2, wherein if the weight change is judged to be greater than the predetermined threshold value, the evaluation result is selected to be given according to the judgment result of the weight change, or the total organic carbon content change is judged to be greater than the predetermined threshold value and the evaluation result is given according to the judgment result of the total organic carbon content change.

5. The method of claim 2, wherein the step (4) comprises:

I. judging whether the molecular weight change is larger than a preset threshold value;

if the molecular weight change is larger than the preset threshold value, judging whether the total organic carbon content change is larger than the preset threshold value;

i. if the change of the total organic carbon content is larger than a preset threshold value, determining that the high polymer material sample can be biodegraded;

determining that the polymeric material sample can only be non-enzymatically hydrolyzed if the change in total organic carbon content is not greater than its preset threshold;

if the molecular weight change is not greater than the preset threshold, judging whether the weight change is greater than the preset threshold;

i. if the weight change is larger than the preset threshold value, further judging whether the change of the total organic carbon content is larger than the preset threshold value;

if the change of the total organic carbon content is not greater than the preset threshold value, determining that the high polymer material sample can only be dissolved;

if the change of the total organic carbon content is larger than a preset threshold value, determining that the high polymer material sample can be biodegraded;

determining that the polymer material sample is difficult to degrade or not degradable if the weight change is not greater than the preset threshold value.

6. The method of claim 1, wherein the molecular weight change is measured by GPC gel permeation chromatography and is characterized by a molecular weight reduction rate; the weight change is measured by a balance and is characterized by weight loss rate; the change of the total organic carbon content is directly measured by a total organic carbon analyzer and an element analyzer and is characterized as the total organic carbon content reduction rate, or the change of the total organic carbon content is indirectly calculated by the release amount of carbon dioxide under aerobic conditions and is characterized as the carbonization rate.

7. The method of claim 6, wherein the predetermined threshold for the rate of molecular weight decrease is 10%, the predetermined threshold for the rate of weight loss is 10%, and the predetermined threshold for the rate of decrease in total organic carbon content or mineralization is 5%.

8. The method of claim 1, wherein the predetermined environment is a simulated marine environment having a temperature of 30 ± 2 ℃ and a microbial content of 10³～10⁷CPU·mL^-1。

9. The method of claim 1, wherein the preset environment is any one of a simulated river water environment, a simulated lake water environment, a PBS buffer solution, a simulated soil environment, and a simulated compost environment.

10. The method of claim 1, wherein the polymer material sample is in the form of a powder, a film, or a block.

11. The method of claim 1, wherein the evaluation conclusion is associated with a predetermined environment, a predetermined length of time, a change in molecular weight, a change in weight, and/or a change in total organic carbon content during degradation.

12. The method according to claim 1, wherein the change of the total organic carbon content during the degradation is estimated by measuring the content of carbonate ions generated after carbon dioxide released under aerobic conditions during the degradation is absorbed by the alkaline solution absorption trap.

13. The method of claim 12, wherein the carbon dioxide released during the degradation process is absorbed by at least one alkaline solution to react with hydrazine to form carbonate ions;

measuring the content of carbonate ions in the alkali solution by using an ion chromatograph;

the total organic carbon content change is estimated based on the measured content of carbonate ions.

Technical Field

The invention relates to a method for evaluating material performance, in particular to a method for evaluating degradation performance of a high polymer material in a preset environment.

Background

The degradation of the polymer material is classified into photodegradation, oxidative degradation, hydrolysis, biodegradation, and the like according to a degradation mechanism. Among them, biodegradation is the most interesting degradation mode and the most widely used degradation mode, and the degradation mode is that the plastics are finally mineralized to form carbon dioxide and water without environmental pollution under the action of environmental microorganisms, usually, the carbon dioxide finally generated in the medium by the high polymer material is used as the core evaluation standard, and the carbon dioxide released in the degradation process of the high polymer material needs to be detected by using instruments such as a respirometer and the like for judgment.

Under the combined action of the structural performance of the high molecular material and environmental factors, the degradation difference of the high molecular material in the same environment is large, and the same high molecular material can present different degradation performances in different environments. However, at present, the concept of the degradation performance of polymer materials at home and abroad is fuzzy, the evaluation method is not sound, the evaluation standard of degradation is not uniform, some photodegradable polymer materials, hydrolytic polymer materials and even water-soluble polymer materials are often mixed with biodegradable polymer materials, and the actual degradation environment cannot be associated when the conclusion of the degradation performance of the polymer materials is given.

Particularly in marine environment, because the marine environment is different from the compost environment and the soil environment which are researched more in temperature and microorganisms, the degradation performance of the polymer material in the marine environment is changed greatly compared with other environments, some traditional biodegradable materials such as PLA and the like can not be degraded quickly in seawater, and a new evaluation method and standard for the degradation performance of the polymer material in the marine special environment are urgently needed.

The existing evaluation standard for the degradation performance of the high polymer material in a special marine environment, for example, ASTM D7081-05, although the standard specification of the biodegradable plastics in a marine environment is given (whether the high polymer material is biodegradable is judged by observing whether the material is not disintegrated, releases carbon dioxide and has no adverse effect on the environment within a certain period of time), the evaluation standard is not given a detailed division for other possible non-biodegradable performances, such as hydrolyzability or water solubility.

Disclosure of Invention

In view of the problems of the existing methods for evaluating the degradation performance of polymer materials, the invention aims to provide a method for comprehensively evaluating the degradation performance of polymer materials, the method can distinguish the biodegradation performance and the non-biodegradation performance by the simplest steps, and the degradation performance obtained by evaluation is associated with the actual test environment.

The method for evaluating the degradation performance of the high polymer material comprises the following steps:

(1) providing a high molecular material sample to be evaluated, and measuring the initial number average molecular weight and the initial weight of the high molecular material sample;

(2) putting the high polymer material sample in a preset environment for degradation for a preset time;

(3) detecting the molecular weight change and the weight change of the high molecular material sample after degradation and the total organic carbon content change in the degradation process;

(4) and judging whether the molecular weight change, the weight change and the total organic carbon content change in the degradation process are larger than respective preset thresholds according to a specified sequence, and giving a degradation performance evaluation conclusion based on the judgment result.

In some embodiments of the invention, the predetermined sequence comprises: firstly, judging whether the molecular weight change is larger than a preset threshold value; and selecting whether the carbon content change is larger than a preset threshold value or not according to the judgment result of the molecular weight change, or judging whether the weight change is larger than the preset threshold value or not. And if the total organic carbon content change is judged to be larger than the preset threshold value, an evaluation conclusion is given according to the judgment result. And if the weight change is selected and judged to be larger than the preset threshold value, an evaluation conclusion is selected and given according to the judgment result of the weight change, or whether the total organic carbon content change is larger than the preset threshold value is judged, and the evaluation conclusion is given according to the judgment result of the total organic carbon content change.

In some embodiments of the invention, step (4) comprises:

I. judging whether the molecular weight change is larger than a preset threshold value;

if the molecular weight change is larger than the preset threshold value, judging whether the total organic carbon content change is larger than the preset threshold value;

i. if the change of the total organic carbon content is larger than a preset threshold value, determining that the high polymer material sample can be biodegraded;

if the change of the total organic carbon content is not greater than the preset threshold value, determining that the macromolecular material sample can only be subjected to non-enzymatic hydrolysis;

if the molecular weight change is not greater than the preset threshold, judging whether the weight change is greater than the preset threshold;

i. if the weight change is larger than the preset threshold value, further judging whether the change of the total organic carbon content is larger than the preset threshold value;

if the change of the total organic carbon content is not greater than the preset threshold value, determining that the high polymer material sample is dissolved;

if the change of the total organic carbon content is larger than a preset threshold value, determining that the high polymer material sample can be biodegraded;

determining that the polymer material sample is difficult to degrade or not degradable if the weight change is not greater than the preset threshold value.

In some embodiments of the invention, wherein the molecular weight change is measured by GPC gel permeation chromatography, characterized by a rate of molecular weight decrease; the weight change is measured by a balance and is characterized by weight loss rate; the change of the total organic carbon content is directly measured by a total organic carbon analyzer and an element analyzer and is characterized as the total organic carbon content reduction rate, or the change of the total organic carbon content is indirectly calculated by the release amount of carbon dioxide under aerobic conditions and is characterized as the carbonization rate. Wherein the preset threshold value of the molecular weight reduction rate is 10%, and when the molecular weight reduction rate is greater than 10%, the molecular weight is considered to be reduced; the preset threshold value of the weight loss rate is 10%, and when the weight loss rate is greater than 10%, the weight loss rate is regarded as weight loss; the preset threshold value of the total organic carbon content reduction rate or the mineralization rate is 5%, and when the total organic carbon content reduction rate is greater than 5% or the mineralization rate is greater than 5%, the carbon dioxide is considered to be released.

In some embodiments of the invention, the predetermined environment may be a simulated marine environment, for example, a temperature of 30 ± 2 ℃ and a microbial load of 10³～10⁷CPU·mL^-1To simulate a marine environment. Alternatively, the preset environment may be any one of a simulated river water environment, a simulated lake water environment, a PBS buffer solution, a simulated soil environment, and a simulated compost environment, as necessary.

In some embodiments of the invention, the sample may be in the form of a film, a powder, or a block.

In some embodiments of the invention, the evaluation conclusion is associated with a predetermined environment and a predetermined time period. In further embodiments, the conclusion of the evaluation of the degradation performance may also show a change in molecular weight, a change in weight and/or a change in total organic carbon content during degradation.

In some embodiments of the present invention, the change in the total organic carbon content during degradation can be estimated by measuring the content of carbonate ions generated after carbon dioxide released under aerobic conditions during degradation is absorbed by the alkaline solution absorption trap. For example, at least one alkali solution is adopted to absorb hydrazine to absorb carbon dioxide released in the degradation process, so that the hydrazine reacts to generate carbonate ions; measuring the content of carbonate ions in the alkali solution by using an ion chromatograph; the total organic carbon content change is estimated based on the measured content of carbonate ions.

Compared with the prior art, the invention has the following beneficial technical effects:

based on the deep analysis of various degradation mechanisms of the high molecular material, the invention selects the molecular weight change, the weight change and the total organic carbon content change in the degradation process as the measurement indexes, designs a unique judgment logic based on the indexes, can comprehensively evaluate the degradation performance of the high molecular material by the simplest steps, can associate the degradation performance with the actual test environment, can embody the degradation performance more objectively, and can accurately distinguish the biodegradation performance from non-enzymatic hydrolysis, dissolution and the like.

Drawings

Fig. 1 shows a schematic flow diagram of an evaluation method according to an embodiment of the invention.

Detailed Description

The present invention will be described in detail with reference to specific examples, which are provided for illustration only and are not intended to limit the scope of the present invention.

In exemplary embodiments of the present invention, any polymer material sample in the form of powder, film or block, such as a resin, a resin composition, a resin alloy, or the like, may be selected. The sample was put into a reaction tank (formed of a simulated marine environment/simulated river water environment/simulated lake water environment/PBS buffer solution/simulated soil environment/simulated compost environment) containing seawater/river water/lake water/PBS buffer solution/soil/compost for degradation, and the reaction tank containing only seawater/river water/lake water/PBS buffer solution/soil/compost/was used as a blank control.

In an exemplary embodiment of the present invention, seawater in a simulated marine environment may be extracted from natural seawater, and then the number of microorganisms in the extracted seawater is adjusted to 10 by controlling the number of microorganisms in the extracted seawater through enrichment, culture or dilution by filtration³-10⁷CPU/mL. The composition and content of inorganic salts, microorganisms and inorganic nutrients required by microorganisms in seawater can be determined by reference to the existing standard (for example, ASTM D6691-2009), and the inorganic nutrients can be adjusted according to the number of microorganisms. The microorganism count can be carried out by a conventional method known in the art, for example, plate count method.

In an exemplary embodiment of the invention, the temperature in the simulated marine environment is chosen to be 30 ℃ and also to float within a suitable range (e.g. + -. 2 ℃), which on the one hand can simulate the marine environment and on the other hand can control the predetermined period of time within a reasonable range, for example within 6 months. In addition, temperature conditions for accelerating degradation may be set to improve the evaluation efficiency.

In an exemplary embodiment of the present invention, the degradation process may be carried out under aerobic conditions, with oxygen being introduced directly into the reaction tank, or with CO being removed₂Gaseous air, e.g. air can be blown into the CO using an air compressor₂Absorption of hydrazine to remove CO₂Gas, CO removal₂The air of the gas is slowly introduced into the reaction tank, and a gas buffer tank and an air flow meter may be provided in the gas flow path as necessary in order to appropriately control the gas flow rate. In addition, CO₂The amount of hydrazine absorbed can be set according to the requirement and can be single CO₂Absorbing hydrazine, optionally more CO₂The absorption hydrazine is used in series.

The change of the total organic carbon content of the system in the degradation process can be directly characterized by testing the change of the total organic carbon content in the sample and the water body before and after degradation, for example, the organic carbon in the sample is measured by an element analyzer, the dissolved organic carbon in the water is tested by using a total organic carbon analyzer, and the total organic carbon content of the system is obtained by adding the total organic carbon content and the dissolved organic carbon content. The change in total organic carbon content can also be indirectly characterized by the respiratory apparatus testing the amount of carbon dioxide released by the system under aerobic conditions.

In an exemplary embodiment of the invention, CO released during degradation of the polymeric material₂Collecting and absorbing the gas by at least one alkali solution with a certain concentration, and if necessary, adding CO to improve the absorption efficiency₂The contact area of the gas and the absorption solution, or a plurality of absorption hydrazines in series. Absorbing alkali solution in hydrazine for absorbing CO₂The gas generates carbonate ions, and the alkali solution is preferably a solution which can easily and rapidly generate water-soluble carbonate ions with carbon dioxide, for example, a NaOH solution or a KOH solution with a proper concentration is selected.

The content of carbonate ions in the solution in the absorbed hydrazine is periodically measured by adopting an anion chromatograph, and the CO generated by degradation is calculated₂When a plurality of absorption hydrazines are used in series, the sum of the absorption amounts of the absorption hydrazines in the same degradation period is calculated.

In an exemplary embodiment of the present invention, the concentration of carbonate ions is measured using an anion chromatograph. The method determines the content of the accumulated generated carbonate ions in the degradation process, further calculates the corresponding accumulated release amount of carbon dioxide, and finally calculates the mineralization rate (namely the degradation rate) of the detected high polymer material so as to represent the change of the carbon content of the sample. And the percentage of the release amount of the carbon dioxide generated cumulatively according to the degradation to the total content of the carbon dioxide theoretically generated by the sample is the mineralization rate.

The mineralization rate of the sample can be calculated according to the following equation 1:

wherein Dt (%) is the mineralization rate (%) of the sample, (CO)₂)_TCumulative carbon dioxide release (mg), (CO) for the samples₂)_BCumulative carbon dioxide Release (mg), ThCO, for blank group₂Theoretical generation of CO for a sample₂Total content (mg) (see equation 2).

In the formula, M_TOTTotal dry solid weight (mg) of the test material (i.e., initial weight of sample), C_TOTThe total organic carbon content (%) of the test material was determined.

In exemplary embodiments of the present invention, carbon dioxide released during degradation may also be detected using other detection means known in the art, such as using a respirator, an infrared spectrometer, a gas chromatograph, an acid-base titrator, and the like.

In an exemplary embodiment of the present invention, the molecular weight of the sample is a number average molecular weight, as measured by GPC gel permeation chromatography, and the weight of the sample is measured by a balance.

The method for evaluating biodegradability of a polymer material according to the present invention will be described below by taking a plurality of polymer materials as examples with reference to the accompanying drawings.

Example 1:

example 1 provides a method for evaluating the degradation performance of PET (polyethylene terephthalate) in a simulated marine environment, comprising the steps of:

(1) a PET (polyethylene terephthalate) sample (sample 1) was provided. The morphology of sample 1 was a thin film. The initial number average molecular weight of sample 1 was 56,130 as measured by GPC, and the initial weight of sample 1 was 0.5g as measured by a balance.

(2) Taking 3L of natural seawater (the content of microorganisms in seawater is determined to be 9,000 CPU. mL by flat plate counting method)^-1The inorganic nutrient comprises 0.5g/L NH₄Cl and 0.1g/L KH₂(PO)₄) Placed in a 5L reaction tank, the reaction tank was placed in a water bath or a vibration device set at a temperature of 30 ℃ to maintain the temperature of seawater in the reaction tank at 30 ℃. Sample 1 was placed in the reaction tank for degradation, under dark conditions, for 6 months.

(3) In the degradation process, carbon dioxide generated by degradation in the reaction tank is continuously introduced into absorption hydrazine containing 0.1mol/L NaOH aqueous solution so that the carbon dioxide reacts with the NaOH to generate carbonate ions, after the expiration of 6 months, the absorption hydrazine solution is extracted from the absorption hydrazine, and the content of the carbonate ions in the extracted absorption hydrazine solution is measured by an IC940 type ion chromatograph. Wherein the IC940 type ion chromatograph uses MetroSep Organic Acids-250/7.8 chromatographic column, and the eluent is 0.5mM H₂SO₄The flow rate is 0.5mL/min, the column temperature is 30 ℃, the quantitative loop is 100 mu L, a 858 autosampler is used for sample injection, and the analysis is carried out by a conductivity detector. The amount of carbon dioxide released was calculated based on the content of carbonate ions, and the mineralization rate of sample 1 was converted from the amount of carbon dioxide released.

The detection shows that the sample 1 does not release carbon dioxide in the degradation process, and the mineralization rate is 0.

Meanwhile, after 6 months had expired, the degraded sample 1 was taken out of the reaction tank, separated, dried, and the number average molecular weight of the degraded sample 1 was 55,569 as measured by GPC, and the weight of the degraded sample 1 was 0.5g as measured by a balance, whereby the molecular weight decrease rate of the sample 1 was 1% and the weight loss rate was 0.

Setting the molecular weight reduction rate, the weight loss rate and the preset threshold value of the total organic carbon content reduction rate or the mineralization rate in the degradation process as follows: the preset threshold value of the molecular weight reduction rate is 10%, and when the molecular weight reduction rate is more than 10%, the molecular weight is considered to be reduced; the preset threshold value of the weight loss rate is 10%, and when the weight loss rate is more than 10%, the weight loss is regarded as weight loss; the preset threshold value of the total organic carbon content reduction rate or the mineralization rate is 5%, and when the total organic carbon content reduction rate is greater than 5% or the mineralization rate is greater than 5%, the carbon dioxide is considered to be released.

(4) Judging whether the molecular weight reduction rate, the weight loss rate and the total organic carbon content reduction rate or the mineralization rate in the degradation process are larger than respective preset threshold values according to the following sequence:

as shown in fig. 1, firstly, it is determined whether the molecular weight reduction rate is greater than a preset threshold, and the molecular weight reduction rate of the sample 1 is 1% and is not greater than the preset threshold; and judging whether the weight loss rate is greater than a preset threshold value or not, wherein the weight loss rate of the sample 1 is 0 and is not greater than the preset threshold value.

The conclusion of the degradation performance evaluation is drawn from this: PET (polyethylene terephthalate) in simulated marine environment (natural seawater, 30 ℃, microorganism 9,000 CPU. mL)^-1) The degradation is not caused in 6 months, the weight loss rate is 0, and the molecular weight reduction rate is 1%.

Example 2:

example 2 provides a method for evaluating the degradation performance of a PLA/PLGA (polylactic acid/polylactic acid-glycolic acid copolymer) blend in a simulated marine environment, comprising the steps of:

(1) a PLA/PLGA (polylactic acid/polylactic acid-glycolic acid copolymer) blend sample (sample 2) is provided. The morphology of sample 2 was a thin film. The initial number average molecular weight of sample 2 was 61,240 as measured by GPC, and the initial weight of sample 2 was 0.5g as measured by a balance.

(2) Taking 3L of natural seawater sediment (the content of microorganisms in seawater is determined to be 1,900 CPU. mL by flat plate counting method detection)^-1The inorganic nutrient comprises 0.5g/L NH₄Cl and 0.1g/L KH₂(PO)₄) Placed in a 5L reaction tank, the reaction tank was placed in a water bath or a vibration device set at a temperature of 30 ℃ to maintain the temperature of seawater in the reaction tank at 30 ℃. Sample 2 was placed in the reaction tank for degradation, under dark conditions, for 3 months.

(3) During the degradation process, the mineralization rate of sample 2 during the degradation process was measured according to the carbon dioxide release detection and scaling method described in example 1. Detection shows that no carbon dioxide is released in the degradation process of the sample 2, and the mineralization rate is 0.

Meanwhile, after 3 months, the degraded sample 2 was taken out of the reaction tank, separated, dried, and the number average molecular weight of the degraded sample 2 was 9,186 as measured by GPC, and the weight of the degraded sample 2 was 0.15g as measured by a balance, whereby the molecular weight decrease rate of the sample 2 was 85% and the weight loss rate was 70%.

Setting the molecular weight reduction rate, the weight loss rate and the preset threshold value of the total organic carbon content reduction rate or the mineralization rate in the degradation process as follows: the preset threshold value of the molecular weight reduction rate is 10%, and when the molecular weight reduction rate is more than 10%, the molecular weight is considered to be reduced; the preset threshold value of the weight loss rate is 10%, and when the weight loss rate is more than 10%, the weight loss is regarded as weight loss; the preset threshold value of the total organic carbon content reduction rate or the mineralization rate is 5%, and when the total organic carbon content reduction rate is greater than 5% or the mineralization rate is greater than 5%, the carbon dioxide is considered to be released.

(4) Judging whether the molecular weight reduction rate, the weight loss rate and the total organic carbon content reduction rate or the mineralization rate in the degradation process are larger than respective preset threshold values according to the following sequence:

as shown in fig. 1, it is first determined whether the molecular weight reduction rate is greater than a preset threshold, and the molecular weight reduction rate of sample 2 is 85%, which is greater than the preset threshold; since the molecular weight reduction rate is greater than the preset threshold, whether the total organic carbon content reduction rate or the mineralization rate is greater than the preset threshold is judged, and the mineralization rate of the sample 2 is 0 and is not greater than the preset threshold.

The conclusion of the degradation performance evaluation is drawn from this: PLA/PLGA (polylactic acid/polylactic acid-glycolic acid copolymer) blend in simulated marine environment (self-simulation marine environment)Seawater sediment, 30 ℃,1,900 CPU.mL of microorganism^-1) Non-enzymatic hydrolysis occurs in 3 months, the weight loss rate is 70%, and the molecular weight reduction rate is 85%.

Example 3:

embodiment 3 provides a method for evaluating degradation performance of PCL (polycaprolactone) in a simulated marine environment, comprising the following steps:

(1) a PCL (polycaprolactone) sample (sample 3) is provided. The form of this sample 3 was a powder form. The initial number average molecular weight of sample 3 was 51,235 as measured by GPC, and the initial weight of sample 3 was 0.5g as measured by a balance.

(2) Taking 3L of natural seawater (the content of microorganisms in seawater is determined to be 90,000 CPU. mL by flat plate counting method)^-1The inorganic nutrient comprises 0.5g/L NH₄Cl and 0.1g/L KH₂(PO)₄) Placed in a 5L reaction tank, the reaction tank was placed in a water bath or a vibration device set at a temperature of 30 ℃ to maintain the temperature of seawater in the reaction tank at 30 ℃. Sample 3 was placed in the reaction tank for degradation, under dark conditions, for 3 months.

(3) During the degradation process, the mineralization rate of the sample 3 during the degradation process was measured according to the carbon dioxide release detection and scaling method described in example 1. The detection shows that carbon dioxide is released in the degradation process of the sample 3, and the mineralization rate of the sample 3 is converted to be 20%.

Meanwhile, after 3 months, the degraded sample 3 was taken out of the reaction tank, separated, dried, and the number average molecular weight of the degraded sample 3 was 5,124 as measured by GPC, and the weight of the degraded sample 3 was 0.15g as measured by a balance, whereby the molecular weight reduction rate of the sample 3 was 90% and the weight loss rate was 80%.

Setting the molecular weight reduction rate, the weight loss rate and the preset threshold value of the total organic carbon content reduction rate or the mineralization rate in the degradation process as follows: the preset threshold value of the molecular weight reduction rate is 10%, and when the molecular weight reduction rate is more than 10%, the molecular weight is considered to be reduced; the preset threshold value of the weight loss rate is 10%, and when the weight loss rate is more than 10%, the weight loss is regarded as weight loss; the preset threshold value of the total organic carbon content reduction rate or the mineralization rate is 5%, and when the total organic carbon content reduction rate is greater than 5% or the mineralization rate is greater than 5%, the carbon dioxide is considered to be released.

(4) Judging whether the molecular weight reduction rate, the weight loss rate and the total organic carbon content reduction rate or the mineralization rate in the degradation process are larger than respective preset threshold values according to the following sequence:

as shown in fig. 1, it is first determined whether the molecular weight reduction rate is greater than a preset threshold, and the molecular weight reduction rate of sample 3 is 90% and greater than the preset threshold; since the molecular weight reduction rate is greater than the preset threshold, whether the total organic carbon content reduction rate or the mineralization rate is greater than the preset threshold is judged, and the mineralization rate of the sample 3 is 20% and is greater than the preset threshold.

The conclusion of the degradation performance evaluation is drawn from this: PCL (polycaprolactone) in simulated marine environment (natural seawater, 30 ℃, microbe 90,000 CPU. mL)^-1) Biodegradation occurs in 3 months, and the molecular weight reduction rate is 90%, the weight loss rate is 70%, and the mineralization rate is 20%.

Example 4:

example 4 provides a method for evaluating the degradation performance of PVA1788 (polyvinyl alcohol) in a simulated marine environment, comprising the steps of:

(1) a sample of PVA1788 (polyvinyl alcohol) is provided (sample 4). The form of this sample 4 was a powder form. The initial number average molecular weight of sample 4 was 62,460 as measured by GPC, and the initial weight of sample 4 was 0.5g as measured by a balance.

(2) Taking 3L of natural seawater (the content of microorganisms in the seawater is determined to be 600 CPU. mL by flat plate counting method detection)^-1The inorganic nutrient comprises 0.5g/L NH₄Cl and 0.1g/L KH₂(PO)₄) Placed in a 5L reaction tank, the reaction tank was placed in a water bath or a vibration device set at a temperature of 30 ℃ to maintain the temperature of seawater in the reaction tank at 30 ℃. Sample 4 was placed in the reaction tank for degradation, under dark conditions, for 2 months.

(3) During the degradation process, the mineralization rate of the sample 4 during the degradation process was measured according to the carbon dioxide release detection and scaling method described in example 1. Detection shows that no carbon dioxide is released in the degradation process of the sample 4, and the mineralization rate is 0.

Meanwhile, after 2 months, the degraded sample 4 was taken out of the reaction tank, separated, dried, and the number average molecular weight of the degraded sample 4 was 62,460 as measured by GPC, and the weight of the degraded sample 4 was 0.05g as measured by a balance, whereby the molecular weight decrease rate of the sample 4 was 0 and the weight loss rate was 90%.

Setting the molecular weight reduction rate, the weight loss rate and the preset threshold value of the total organic carbon content reduction rate or the mineralization rate in the degradation process as follows: the preset threshold value of the molecular weight reduction rate is 10%, and when the molecular weight reduction rate is more than 10%, the molecular weight is considered to be reduced; the preset threshold value of the weight loss rate is 10%, and when the weight loss rate is more than 10%, the weight loss is regarded as weight loss; the preset threshold value of the total organic carbon content reduction rate or the mineralization rate is 5%, and when the total organic carbon content reduction rate is greater than 5% or the mineralization rate is greater than 5%, the carbon dioxide is considered to be released.

(4) Judging whether the molecular weight reduction rate, the weight loss rate and the total organic carbon content reduction rate or the mineralization rate in the degradation process are larger than respective preset threshold values according to the following sequence:

as shown in fig. 1, it is first determined whether the molecular weight decrease rate is greater than a preset threshold, and the molecular weight decrease rate of the sample 4 is 0 and is not greater than the preset threshold; since the molecular weight reduction rate is not greater than the preset threshold, judging whether the weight loss rate is greater than the preset threshold, wherein the weight loss rate of the sample 4 is 90 percent and is greater than the preset threshold; and judging whether the total organic carbon content reduction rate or the mineralization rate is greater than a preset threshold value or not, wherein the mineralization rate of the sample 4 is 0 and is not greater than the preset threshold value.

The conclusion of the degradation performance evaluation is drawn from this: PVA1788 (polyvinyl alcohol) in simulated marine environment (natural seawater, 30 ℃, microbe 600CPU & mL)^-1) The dissolution occurs in 2 months and no biodegradation occurs, the molecular weight reduction rate is 0, and the weight loss rate is 90%.

Example 5:

example 5 provides a method for evaluating the degradation performance of PLA (polylactic acid) in a PBS buffer environment, comprising the following steps:

(1) a PLA (polylactic acid) sample (sample 5) is provided. The form of this sample 5 was a film form. The initial number average molecular weight of sample 5 was 60,120 as measured by GPC, and the initial weight of sample 5 was 0.5g as measured by a balance.

(2) 3L of PBS buffer (the microbial content in the PBS buffer is 600 CPU. mL)^-1pH 8.5) was placed in a 5L reaction tank, and the reaction tank was placed in a water bath or a vibration device set at 60 ℃ to maintain the PBS buffer solution in the reaction tank at 60 ℃. Sample 5 was placed in the reaction tank for degradation, under dark conditions, for 3 months.

(3) During the degradation process, the mineralization rate of the sample 5 during the degradation process was measured according to the carbon dioxide release detection and scaling method described in example 1. Detection shows that no carbon dioxide is released in the degradation process of the sample 5, and the mineralization rate is 0.

Meanwhile, after 3 months, the degraded end product was taken out of the reaction tank, separated, dried, and the number average molecular weight of the degraded sample 5 was 9,018 as measured by GPC, and the weight of the degraded sample 5 was 0.15g as measured by a balance, whereby the molecular weight reduction rate of the sample 5 was 85% and the weight loss rate was 70%.

Setting the molecular weight reduction rate, the weight loss rate and the preset threshold value of the total organic carbon content reduction rate or the mineralization rate in the degradation process as follows: the preset threshold value of the molecular weight reduction rate is 10%, and when the molecular weight reduction rate is more than 10%, the molecular weight is considered to be reduced; the preset threshold value of the weight loss rate is 10%, and when the weight loss rate is more than 10%, the weight loss is regarded as weight loss; the preset threshold value of the total organic carbon content reduction rate or the mineralization rate is 5%, and when the total organic carbon content reduction rate is greater than 5% or the mineralization rate is greater than 5%, the carbon dioxide is considered to be released.

(4) Judging whether the molecular weight reduction rate, the weight loss rate and the total organic carbon content reduction rate or the mineralization rate in the degradation process are larger than respective preset threshold values according to the following sequence:

as shown in fig. 1, firstly, it is determined whether the molecular weight reduction rate is greater than a preset threshold, and the molecular weight reduction rate of the sample 5 is 85% and is greater than the preset threshold; and judging whether the total organic carbon content reduction rate or the mineralization rate is greater than a preset threshold value or not, wherein the mineralization rate of the sample 5 is 0 and is not greater than the preset threshold value.

The conclusion of the degradation performance evaluation is drawn from this: PLA (polylactic acid) in PBS buffer solution environment (60 ℃, microbial 600CPU & mL)^-1) Non-enzymatic hydrolysis occurs in 3 months, the weight loss rate is 70%, and the molecular weight reduction rate is 85%.

Example 6:

example 6 provides a method for evaluating the degradation performance of PHB (poly- β -hydroxybutyrate) in a simulated river environment, comprising the steps of:

(1) a PHB (poly- β -hydroxybutyrate) sample (sample 6) was provided. The form of this sample 6 was a powder form. The initial number average molecular weight of sample 6 was 68,926 as measured by GPC, and the initial weight of sample 6 was 0.5g as measured by a balance.

(2) Taking 3L of natural river water (the microorganism content in the river water is 900,000 CPU. mL by plate counting method detection)^-1) Placed in a 5L reaction tank, the reaction tank was placed in a water bath or a vibration device set at a temperature of 30 ℃ to maintain the river water temperature in the reaction tank at 30 ℃. Sample 6 was placed in the reaction tank for degradation, under dark conditions, for 3 months.

(3) During the degradation process, the mineralization rate of the sample 6 during the degradation process was measured according to the carbon dioxide release detection and scaling method described in example 1. The detection shows that carbon dioxide is released in the degradation process of the sample 6, and the mineralization rate of the sample 6 is 40% through conversion.

Meanwhile, after 3 months, the degraded sample 6 was taken out of the reaction tank, separated, dried, and the number average molecular weight of the degraded sample 6 was 6,893 as measured by GPC, and the weight of the degraded sample 6 was 0.1g as measured by a balance, whereby the molecular weight reduction rate of the sample 6 was 90% and the weight loss rate was 80%.

Setting the molecular weight reduction rate, the weight loss rate and the preset threshold value of the total organic carbon content reduction rate or the mineralization rate in the degradation process as follows: the preset threshold value of the molecular weight reduction rate is 10%, and when the molecular weight reduction rate is more than 10%, the molecular weight is considered to be reduced; the preset threshold value of the weight loss rate is 10%, and when the weight loss rate is more than 10%, the weight loss is regarded as weight loss; the preset threshold value of the total organic carbon content reduction rate or the mineralization rate is 5%, and when the total organic carbon content reduction rate is greater than 5% or the mineralization rate is greater than 5%, the carbon dioxide is considered to be released.

(4) Judging whether the molecular weight reduction rate, the weight loss rate and the total organic carbon content reduction rate or the mineralization rate in the degradation process are larger than respective preset threshold values according to the following sequence:

as shown in fig. 1, it is first determined whether the molecular weight reduction rate is greater than a preset threshold, and the molecular weight reduction rate of sample 6 is 90% and greater than the preset threshold; and judging whether the total organic carbon content reduction rate or the mineralization rate is greater than a preset threshold value or not, wherein the mineralization rate of the sample 6 is 40% and is greater than the preset threshold value.

The conclusion of the degradation performance evaluation is drawn from this: PHB (Poly-beta-hydroxybutyrate) in simulated river water environment (30 ℃, microorganism 900,000CPU & mL)^-1) Biodegradation occurs in 3 months, the weight loss rate is 80 percent, the molecular weight reduction rate is 90 percent, and the mineralization rate is 40 percent.

The present invention has been described in detail with reference to the specific embodiments, which are exemplary only, and are not intended to limit the scope of the present invention, and those skilled in the art may make various modifications, changes, or alterations to the present invention without departing from the spirit and scope of the present invention. Therefore, various equivalent changes made in accordance with the present invention are also within the scope of the present invention.