Photodegradable / biodegradable materials and methods for making the same

Abstract

The application provides a photobiodegradable material, which comprises degradable microspheres prepared by blending polylactic acid, polycaprolactone and a photosensitizer; the degradable microspheres are prepared by polymerization of at least 66-92 parts of polylactic acid, 4-30 parts of polycaprolactone and 0.2-5 parts of the photosensitizer by weight. The photobiodegradable material has a simple preparation method, and by changing the preparation process and raw materials, a composite material with controllable microsphere size, uniform particle size and photodegradation performance and biodegradation performance is obtained, which greatly improves the poor degradation efficiency of the biodegradable material under seawater conditions.

Description

TECHNICAL FIELD

[0001] The present application relates to a kind of degradable materials and the preparation method of degradable material, specifically a kind of light / biodegradable material and its preparation method. BACKGROUND

[0002] The seriousness of marine pollution has attracted great attention of mankind, and the "white garbage" caused by non-degradable plastics has caused numerous marine organisms to be on the brink of extinction, and the marine ecosystem has been severely damaged. According to statistics, about 10 million tons of various types of garbage enter the ocean every year through various means, and the natural degradation of non-degradable plastics takes about 100-200 years. These large amounts of non-degradable garbage can cause great harm to marine organisms and the entire marine ecological environment.

[0003] At present, degradable materials are developing rapidly and are widely used in various industries. Most of the plastic garbage accumulated in the ocean is non-degradable packaging material, and the application of degradable materials in the packaging field will greatly improve the problem of marine pollution, but typical biodegradable materials do not exhibit the same degradation rate and degradation efficiency in seawater environment as in ordinary environment, and even some degradable materials do not degrade in seawater environment. Studies have shown that conventional PLA does not degrade in natural seawater within one year, and there is no significant change in molecular weight, weight loss, and mechanical properties; conventional PCL shows surface corrosion mechanism in natural seawater, and as the degradation process progresses, the material size gradually decreases but the molecular weight and mechanical properties remain unchanged.

[0004] Therefore, there is an urgent need for a new type of degradable material that can degrade rapidly in seawater without affecting the marine ecological environment. SUMMARY

[0005] In order to solve the above problems of the prior art, the present application provides a kind of light / biodegradable material and preparation method that can be quickly degraded in seawater.

[0006] The technical problem to be solved by the present application is solved by the following technical solution:

[0007] The present application provides a kind of light / biodegradable material, the light / biodegradable material includes at least the degradable microspheres prepared by blending polylactic acid, polycaprolactone and photosensitizer;The degradable microspheres are prepared by at least 70-95 parts of polylactic acid, 5-30 parts of polycaprolactone and 0.2-5 parts of photosensitizer by weight.

[0008] Further, the particle size of the degradable microspheres is 10-100 μm.

[0009] A preparation method for preparing the above-mentioned light / biodegradable material, comprising the following steps:

[0010] Step one, take polylactic acid, polycaprolactone master batch mixed, and the mixed polylactic acid, polycaprolactone master batch is dissolved in organic solvent, and add photosensitizer and solubilizer, get the dispersed phase solution; Take polyvinyl alcohol, and polyvinyl alcohol is added to deionized water, and the continuous phase solution is configured.

[0011] Step two, the dispersed phase solution prepared in step one is injected into the continuous phase solution to obtain a mixed solution 1 containing uniform droplets;

[0012] Step three, the mixed solution 1 obtained in step two is subjected to ultrasonic atomization to obtain a mixed solution 2;

[0013] Step four, the mixed solution 2 in step three is filtered, washed and dried to obtain the light / biodegradable material.

[0014] Further, in step one, the mass ratio of polylactic acid master batch, polycaprolactone master batch, photosensitizer and solubilizer is 7-20:1-3.

[0015] Further, in step one, the amount of photosensitizer and solubilizer is 0.2-5% of the total weight of polylactic acid master batch and polycaprolactone master batch.

[0016] Further, in step one, the photosensitizer is selected from at least one of iron stearate, benzophenone, anthrone, anthraquinone, 4,4-di-tert-butyl benzophenone, 4-tert-butyl benzophenone, 3,4-dihydroxybenzaldehyde, stearate, dialkyldithiocarbamate; the organic solvent is selected from at least one of dichloromethane, acetone, ethyl acetate, dimethylformamide;

[0017] Further, in step one, the concentration of the dispersed phase solution is 1%-5%; the concentration of the continuous phase solution is 1%-5%.

[0018] Further, in step two, the dispersed phase solution is injected into the continuous phase solution through a sharp hole, the inner diameter of the sharp hole is 0.01-0.1mm, the injection rate of the dispersed phase solution is 0.5-2mL / min; the flow rate of the continuous phase is 1000-3000r / min.

[0019] Further, in step three, the flow rate of ultrasonic atomization spray is 10-5m3 / s-10-4m3 / s, and the ultrasonic spray time is 0.5-1h.

[0020] Further, in step four, the drying temperature is 40-80℃, and the drying time is 12-36h.

[0021] The application provides a photobiodegradable material, and the preparation method is simple, the composite material with controllable microsphere size, uniform particle size and photodegradation performance and biodegradation performance is obtained by changing the preparation process and raw materials, and the degradation efficiency of the biodegradable material under seawater conditions is greatly improved. DETAILED DESCRIPTION

[0022] It should be noted that the embodiments and features in the embodiments in the present application can be combined with each other without conflict.

[0023] It should be pointed out that the following detailed description is exemplary and is intended to provide further description of the present application. Unless otherwise specified, all technical and scientific terms used herein have the same meaning as understood by those skilled in the art to which the present application belongs.

[0024] It should be noted that the terms used herein are only for describing the specific embodiments, and are not intended to limit the exemplary embodiments according to the present application. As used herein, unless the context clearly indicates otherwise, the singular form is intended to include the plural form, and in addition, it should be understood that when the terms "comprise" and / or "include" are used in the specification, it means that there is a feature, step, operation, device, component and / or combination thereof.

[0025] The application will be described in detail below with reference to the embodiments.

[0026] A photobiodegradable material, the photobiodegradable material comprising a degradable microsphere prepared by blending at least polylactic acid, polycaprolactone and a photosensitizer; the degradable microsphere comprising at least 70-95 parts of polylactic acid, 5-30 parts of polycaprolactone and 0.2-5 parts of the photosensitizer by weight.

[0027] Further, the particle size of the degradable microsphere is 10-100 μm.

[0028] Specifically, a kind of light / biodegradable material, the degradation material can be introduced by photosensitive group in biodegradable material, using multiple degradation mechanisms such as photodegradation and hydrolysis, synergistically improve the degradation rate of material in seawater conditions, i.e. the light / biodegradable material refers to the degradable material that can be photodegraded and biodegraded. The main components of the light / biodegradable material include at least the degradable microspheres prepared by blending polylactic acid, polycaprolactone and photosensitizer;The degradable microspheres include at least 70-95 parts of polylactic acid, 5-30 parts of polycaprolactone and 0.2-5 parts of photosensitizer polymerized by weight parts;Polycaprolactone PCL and polylactic acid PLA are biodegradable materials, and have good biocompatibility, but there is a big difference in degradation time. The polylactic acid PLA modified by polycaprolactone PCL can obtain the degradable material with the degradation rate required by specific needs. In order to further improve the degradation rate, photosensitive group is introduced to further assist photodegradation on the basis of biodegradation, improve the degradable performance of the material, especially the degradation efficiency in seawater will be greatly improved. The conventional polylactic acid is irregular granular or blocky, the porous microspheres prepared in the application have larger specific surface area, and the contact of larger area with water is beneficial to the occurrence of polylactic acid / polycaprolactone microsphere hydrolysis reaction, but more pores lead to the decrease of the mechanical properties of the degradable microspheres, which has defects in actual use.

[0029] The light / biodegradable material mainly includes degradable microspheres with porous microsphere morphology, especially, the particle size of the degradable microspheres is 10-100 μm, the specific surface area of the degradable microspheres is large, and the stability is good. When the particle size of the degradable microspheres exceeds 100 μm, the specific surface area of the degradable microspheres decreases, and it is difficult to realize efficient degradation. When the particle size of the degradable microspheres is less than 10 μm, the manufacturing cost of the degradable microspheres is high, and the size is difficult to control, which is difficult to be practically applied.

[0030] A preparation method for preparing the light / biodegradable material described above, comprising the following steps:

[0031] Step one, take polylactic acid, polycaprolactone granules and mix them, and dissolve the mixed polylactic acid, polycaprolactone granules in organic solvent, and add photosensitizer and solubilizer to obtain a dispersion phase solution;Take polyvinyl alcohol, and add polyvinyl alcohol to deionized water to prepare a continuous phase solution.

[0032] Step two, inject the dispersion phase solution prepared in step one into the continuous phase solution to obtain a mixed solution 1 containing uniform droplets;

[0033] Step three, ultrasonic atomize the mixed solution 1 obtained in step two to obtain a mixed solution 2;

[0034] Step four, filtering, washing and drying the mixed solution 2 in step three to obtain the light / biodegradable material.

[0035] Specifically, the preparation method of the light / biodegradable material, in particular the preparation method of the degradable microspheres, comprises the following steps:

[0036] Step one, drying polylactic acid and polycaprolactone, mixing the dried polylactic acid and polycaprolactone masterbatch according to a certain proportion, dissolving the mixed polylactic acid and polycaprolactone masterbatch in an organic solvent, and adding a photosensitizer and a solubilizing agent to obtain a dispersed phase solution.

[0037] In the dispersed phase solution, the mass ratio of the polylactic acid masterbatch and the polycaprolactone masterbatch is 7-20:1-3; and the photosensitizer and the solubilizing agent are also included, and the amount of the photosensitizer added is 0.2-5% of the total weight of the polylactic acid masterbatch and the polycaprolactone masterbatch.

[0038] When the ratio of polylactic acid to polycaprolactone is less than 7:3, the mechanical properties of the prepared degradable microspheres are insufficient due to the excessive content of polycaprolactone, and it is difficult to meet the actual application. When the ratio of polylactic acid to polycaprolactone exceeds 20:1, the particle size of the degradable microspheres decreases due to the excessive content of polylactic acid masterbatch. The content of the photosensitizer is too low, which leads to insufficient photodegradation efficiency and makes it difficult to achieve high degradation rate. The content of the photosensitizer is too high, which leads to excessive degradation performance of the degradable microspheres, and the degradable microspheres begin to degrade during normal use, which cannot meet the normal use. From the perspective of degradation performance and actual use mechanical properties, the mass ratio of the polylactic acid masterbatch and the polycaprolactone masterbatch is preferably 7-20:1-3; and the photosensitizer and the solubilizing agent are also included, and the amount of the photosensitizer added is 0.2-5% of the total weight of the polylactic acid masterbatch and the polycaprolactone masterbatch.

[0039] Further, the concentration of the dispersed phase solution is 1%-5%. When the concentration of the dispersed phase exceeds 5%, the particle size of the final degradable microspheres is too large, the specific surface area is reduced, and the degradation performance is insufficient. When the concentration of the dispersed phase is less than 1%, the particle size of the microspheres is too small.

[0040] Further, take polyvinyl alcohol and add it to deionized water to prepare a continuous phase solution.

[0041] Further, the concentration of the continuous phase solution is 1%-5%.

[0042] Further, in step one, the photosensitizer is selected from at least one of iron stearate, benzophenone, anthrone, anthraquinone, 4,4-di-tert-butyl benzophenone, 4-tert-butyl benzophenone, 3,4-dihydroxybenzaldehyde, stearate, dialkyldithiocarbamate; the solubilizing agent is selected from at least one of L-lysine triisocyanate (LTI), glycidyl methacrylate (GMA); the organic solvent is selected from at least one of dichloromethane, acetone, ethyl acetate, dimethylformamide.

[0043] Step two, inject the dispersion phase solution prepared in step one into the continuous phase solution to obtain a mixed solution 1 containing uniform droplets;

[0044] Specifically, the dispersion phase solution prepared in step one is injected into the continuous phase solution through a sharp hole with an inner diameter of 0.01-0.1 mm, and the injection rate is controlled by a push pump, and the injection rate of the dispersion phase solution is 0.5-2 mL / min. The dispersion phase solution is injected into the continuous phase solution through a needle with a small enough hole diameter, and a constant push pump is connected behind the needle to achieve the injection. The inner diameter of the needle should be adapted to the injection rate and stirring rate, and too large or too small will cause the microspheres to be difficult to form.

[0045] The injection rate and shear rate are matched, the purpose of injection is to hope that the dispersion phase can be regularly and uniformly distributed in the continuous phase, and the interaction of the injection force and shear force received by the dispersion phase when injected makes the dispersion phase into a spherical liquid dispersed in the aqueous solution. The formation of such spherical droplets is beneficial to the subsequent evaporation of the solvent to form microspheres.

[0046] When the dispersion droplets at the needle tip grow to the target size, they are sheared off by the continuous phase. The flow rate of the continuous phase is regulated by the rate of mechanical stirring, if the flow rate of the continuous phase at the needle tip is constant, the size of the droplets sheared off each time is also basically consistent, that is, droplets with consistent particle size can be obtained. The flow rate of the continuous phase is 1000-3000 r / min.

[0047] Step three, ultrasonic atomization of the mixed solution 1 obtained in step two to obtain a mixed solution 2;

[0048] Specifically, in step three, the flow rate of ultrasonic atomization spraying is 10 -5 m 3 / s-10 -4 m 3 / s, and the ultrasonic spraying time is 0.5-1 h. The purpose of spraying is to make the solvent more uniformly volatilize, and generally the slower the flow rate of ultrasonic atomization, the longer the time, the smaller the size of the microspheres obtained. In order to realize the size of the degradable microspheres within a reasonable range, the flow rate of ultrasonic atomization spraying is preferably 10 -5 m 3 / s-10-4 m 3 / s, the ultrasonic atomization time is 0.5-1h.

[0049] Step four, filtering, washing and drying the obtained solid in the mixed solution 2 in step three to obtain the light / biodegradable material.

[0050] Further, in step four, the obtained solid is collected and washed and dried with deionized water. That is, monodisperse composite polylactic acid / polycaprolactone photosensitive microspheres are obtained, the drying temperature is 40-80℃, and the drying time is 12-36h.

[0051] The preparation method of the light / biodegradable material is simple, and by changing the preparation process and raw materials, the composite material with controllable microsphere size, uniform particle size and light degradation performance is obtained, which greatly improves the poor degradation efficiency of biodegradable materials in seawater conditions.

[0052] Further illustrated by specific examples:

[0053] The dried polylactic acid and polycaprolactone master batch are weighed according to a ratio of 7-20:1-3, a total of 100 parts by weight, and mixed, the mixed master batch is dissolved in dichloromethane, and 0.2-5 parts by weight of photosensitizer and 0.2-5 parts by weight of solubilizer are added to the blending system, and a dispersion phase solution with a concentration of 1%-5% is prepared;

[0054] The polyvinyl alcohol is added to deionized water, stirred and heated to completely dissolve, and a continuous phase solution with a concentration of 1%-5% is prepared;

[0055] The dispersion phase solution is injected into the continuous phase solution through a needle with a sharp hole inner diameter of 0.01-0.1mm, the injection rate is controlled by a push pump, the dispersion phase solution injection rate is 0.5-2mL / min, and the mechanical stirring rate is controlled to be 1000-3000r / min, at this time, the flow rate of the continuous phase and the mechanical stirring rate are consistent;

[0056] Finally, the mixed solution is ultrasonically atomized, the flow rate during spraying is 10 -5 m 3 / s-10 -4 m 3 / s, the ultrasonic atomization time is 0.5-1h.

[0057] The obtained solid is collected, washed and dried with deionized water, the drying temperature is 40-80℃, and the drying time is 12-36h, to obtain the light / biodegradable material.

[0058] The specific operation parameters and performance test data of Examples 1-26 and Comparative Example 1 are shown in Table 1.

[0059] Table 1

[0060]

[0061]

[0062] Test method:

[0063] Particle size test:

[0064] Take a photo with an optical electron microscope, and count more than 500 microspheres at a time.

[0065] Calculate the average particle size d0, particle size standard deviation std, and particle size distribution coefficient CV:

[0066]

[0067] Degradation rate test:

[0068] Preparation of test bars: After drying the light / biodegradable materials prepared in the examples and comparative examples in a vacuum oven at 45-80°C for 48h, standard tensile test bars were processed on an injection molding machine according to GB / T1040-92, with an effective length (G0) of (25±1) mm, a width (b) of (6.0±0.4) mm, and a thickness (d) of (2.0±0.2) mm.

[0069] Degradation experiment: Each test bar was numbered and weighed, and then placed in the prepared water body. The water body simulating seawater was placed in a glass water tank, and the water level was marked with a scale. During the experiment, due to the continuous evaporation of the water body, distilled water was added to maintain the water level. To maintain the salinity of the water body, the water sample was replaced every 14 days. The water body was prepared as follows: in 20L of distilled water, add 483.38g of NaCl, 103.94g of MgCl2, 22.76g of CaCl2, 14.91g of KCl, 81.04g of Na2SO4, 4.19g of NaHCO3, 1.67g of NaBr, and then add 5‰ of the water body mass of Kason antibacterial agent. The temperature and light were both in the natural environment. The degradation rate of the test bars was tested by periodically sampling, cleaning, and drying.

[0070] The measured experimental data are shown in Table 2:

[0071] Table 2

[0072] Example Average particle size d0 (um) cv Degradation rate Example 1 30-70 16％ 91％ Example 2 60-100 37％ 85％ Example 3 20-50 12％ 71％ Example 4 10-20 7％ 59％ Example 5 30-80 20％ 85％ Example 6 40-90 23％ 79％ Example 7 40-100 29％ 77％ Example 8 40-100 35％ 62％ Example 9 10-40 20％ 81％ Example 10 20-60 22％ 73％ Example 11 20-80 31％ 66％ Example 12 20-100 35％ 65％ Example 13 20-40 18％ 81％ Example 14 20-40 11％ 83％ Example 15 20-40 18％ 79％ Example 16 20-50 20％ 87％ Example 17 20-30 16％ 91％ Example 18 20-30 19％ 92％ Example 19 10-40 23％ 88％ Example 20 5-20 15％ 89％ Example 21 5-20 13％ 91％ Example 22 5-20 10％ 93％ Example 23 5-20 8％ 93％ Example 24 5-20 10％ 93％ Example 25 20-40 24％ 84％ Example 26 20-60 35％ 73％ Comparative Example 1 100-200 42％ 37％

[0073] According to the above experimental data, the light / biodegradable material prepared in the examples has controllable microsphere size, uniform particle size, and excellent seawater degradation efficiency. In Comparative Example 1, no photosensitizer was added, and the corresponding degradable material did not have light degradation performance, and the degradation rate in seawater was the lowest.

[0074] The above merely provides the preferred embodiments of the present application, and is not intended to limit the present application. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall fall within the scope of protection of the present application.

Claims

1. A photo / biodegradable material, characterized by, The light / biodegradable material comprises biodegradable microspheres prepared by blending polylactic acid, polycaprolactone and photosensitizer; the biodegradable microspheres are prepared by at least 70-95 parts of polylactic acid, 5-30 parts of polycaprolactone and 0.2-5 parts of photosensitizer by weight; the biodegradable microspheres have a porous morphology; and the particle size of the biodegradable microspheres is 10-100 μm.

2. A process for the preparation of the photo / biodegradable material according to claim 1, characterized in that, The method comprises the following steps: Step one, mix polylactic acid masterbatch and polycaprolactone masterbatch, dissolve the mixed polylactic acid and polycaprolactone masterbatch in an organic solvent, and add photosensitizer and solubilizer to obtain a dispersed phase solution; take polyvinyl alcohol, and add the polyvinyl alcohol to deionized water to prepare a continuous phase solution; Step two, inject the dispersed phase solution prepared in step one into the continuous phase solution to obtain a mixed solution 1 containing uniform droplets; Step three, perform ultrasonic atomization on the mixed solution 1 obtained in step two to obtain a mixed solution 2; Step four, filter, wash and dry the mixed solution 2 in step three to obtain the light / biodegradable material.

3. The preparation method according to claim 2, characterized in that, In step one, the mass ratio of the polylactic acid masterbatch to the polycaprolactone masterbatch is 7-20:1-3.

4. The production method according to claim 2, characterized by, In step one, the amount of the photosensitizer and the solubilizer added is 0.2-5% of the total weight of the polylactic acid masterbatch and the polycaprolactone masterbatch by weight.

5. The preparation method according to claim 2, characterized in that, In step one, the photosensitizer is at least one selected from the group consisting of iron stearate, benzophenone, anthrone, anthraquinone, 4,4-di-tert-butyl benzophenone, 4-tert-butyl benzophenone, 3,4-dihydroxybenzaldehyde, stearate, and dialkyldithiocarbamate; and the organic solvent is at least one selected from the group consisting of dichloromethane, acetone, ethyl acetate and dimethylformamide.

6. The preparation method according to claim 2, characterized in that, In step one, the concentration of the dispersed phase solution is 1-5%, and the concentration of the continuous phase solution is 1-5%.

7. The preparation method according to claim 2, characterized in that, In step two, the dispersed phase solution is injected into the continuous phase solution through a sharp hole, the inner diameter of the sharp hole is 0.01-0.1 mm, the injection rate of the dispersed phase solution is 0.5-2 mL / min, and the flow rate of the continuous phase is 1000-3000 r / min.

8. The preparation method according to claim 2, characterized in that, In step three, the spray flow rate during the ultrasonic atomization stage is 10. -5 m 3 / s-10 -4 m 3 / s, the spraying time in the ultrasonic atomization stage is 0.5-1h.

9. The preparation method according to claim 2, characterized in that, In step four, the drying temperature in the drying stage is 40-80℃, and the drying time is 12-36 h.

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