Composite degradation accelerant, controllable degradation biological material and preparation method of controllable degradation biological material

Abstract

The invention discloses a composite degradation accelerant, a controllable degradation polyester composite material and a preparation method of the controllable degradation polyester composite material. According to the invention, the halloysite-loaded degradation accelerant is used for coating the degradation bacterium spores to form a core-shell structure, so that the composite degradation accelerant is obtained, the thermal stability of the degradation bacterium spores is improved, and the degradation bacterium spores can be subjected to thermal processing with biodegradable polyester; through the synergistic effect of the composite degradation accelerant and the degrading bacteria, the biodegradation rate of the biodegradable material is regulated and controlled; the composite degradation accelerant and biodegradable polyester are blended and compounded, and the degradation rate is regulated and controlled through the design of the load rate and the raw material ratio, so that the problem of poor controllability of the degradation rate of the existing biodegradable material is solved; the production process is simple, and the existing biodegradable polyester modification production line is adopted, so that large-scale industrial production can be realized.

Description

TECHNICAL FIELD

[0001] The present application belongs to the field of high polymer materials, and particularly relates to a composite degradation promoter, a controllable degradable biomaterial and a preparation method thereof. BACKGROUND

[0002] Biodegradable plastics are one of the effective means to prevent plastic pollution, and relevant research and application are increasingly valued. At present, the most widely used biodegradable plastics are polybutylene adipate terephthalate (PBAT) and polylactic acid (PLA), both of which can be completely degraded into water and carbon dioxide within 180 days under composting conditions, showing excellent biodegradation performance. In the environment such as soil, river and seawater, the sensitivity of biodegradable plastics to microbial degradation is relatively low, and the complete degradation time will be greatly prolonged. In actual use, the ideal biodegradable plastic is stable during use, and requires the material to have a faster degradation rate after being discarded, especially in natural environments such as soil and water.

[0003] At present, the main methods for regulating the degradation rate of biodegradable plastics are molecular structure design and plastic alloy design. Molecular structure design can realize precise control of the degradation rate, form special polymers that meet application requirements, and often needs to go through processes such as catalyst design, polymerization process exploration and structure-activity relationship matching, and the process is relatively complex and industrial application must adjust the preparation process. Plastic alloy design is a new material with high performance, functionalization and specialization obtained by using physical blending or chemical grafting method for biodegradable resin, and cannot significantly reduce the cost of the obtained product. Therefore, how to construct a biodegradable material with low cost, simple process and good controllability of degradation performance is a technical problem to be solved in the field.

[0004] Hormite nanotube is a kind of natural nanotube material formed by rolling the double-layer sheet structure of silicon oxide and aluminum oxide. In aqueous solution, the outer tube wall of hormite nanotube is negatively charged, and the inner tube wall is positively charged. Loading functional preparations such as preservatives, drugs, enzymes and DNA in the lumen of hormite can endow hormite with functionality to achieve slow release. Compared with directly adding functional preparations to composite materials, the method of loading functional preparations with hormite nanotube can reduce the cumulative release rate and prolong the action time. Hormite nanotube is obtained by sintering, grinding and purifying clay ore, which is abundant in reserves and low in price, and is suitable for large-scale application. The composite material prepared by blending hormite with biodegradable resin can effectively reduce the cost of biodegradable products. Patent CN118955972A discloses a high-weather-resistant biodegradable mulch film, which uses hormite chemical grafting and physical adsorption method to load anti-aging auxiliary agent, and is blown into film after being compounded with PBAT / PLA. The obtained mulch film has better anti-aging performance. Patent CN114181500A discloses that by loading lipase complex with hormite and compounding with polybutylene succinate, a high aliphatic polyester composite material with improved mechanical properties and degradation performance is prepared. However, there are still needs to reduce the loss of enzyme activity and improve the controllability of material degradation rate for the industrial application of biodegradable materials with controllable degradation rate. SUMMARY

[0005] The purpose of the present application is to overcome the shortcomings of the prior art, and to provide a composite degradation promoter. The composite degradation promoter is obtained by loading a degradation promoter in hormite nanotubes to form a slow-release degradation promoter component, and then coating spores of a degradation bacterium to form a composite degradation promoter with a core-shell structure. The slow-release degradation promoter and the spores of the degradation bacterium work together to regulate the degradation rate of a biodegradable polyester composite material.

[0006] Another purpose of the present application is to provide a polyester composite material with controllable degradation rate, which comprises the composite degradation promoter. The composite degradation promoter is blended and compounded with a polyester, preferably a biodegradable polyester, to regulate the degradation rate through the design of the raw material ratio of the composite material. The production process is simple, and the existing biodegradable polyester modification production line can be used for large-scale industrial production.

[0007] The purpose of the present application is achieved by the following technical solutions.

[0008] The first aspect of the present application provides a composite degradation promoter comprising microparticles with a core-shell structure, wherein the microparticles have spores of a degradation bacterium as the core and hormite loaded with a degradation promoter as the shell, and the degradation promoter is selected from at least one of nitrogen-containing compounds, phosphate compounds, lipase, esterase and cutinase.

[0009] According to the present application, in the composite degradation promoter:

[0010] The degrading bacterial spores are selected from at least one of Bacillus subtilis spores, Bacillus licheniformis spores, Bacillus caldovelox spores, Brevibacillus laterosporus spores, Bacillus megaterium spores, Bacillus mycoides spores, Bacillus azoreus spores, and Bacillus sphaericus spores; and / or,

[0011] The halloysite can be a common halloysite natural material, for example, the inner tube diameter of the halloysite is 10-100 nm, and the length is 200-2000 nm, preferably, the inner tube diameter of the halloysite is 20-50 nm, and the length is 500-1500 nm; and / or,

[0012] The nitrogen-containing compound is selected from at least one of urea, ammonium sulfate, and ammonium bicarbonate; and / or,

[0013] The phosphate compound is selected from at least one of dipotassium hydrogen phosphate, potassium dihydrogen phosphate, disodium hydrogen phosphate, and sodium dihydrogen phosphate; and / or,

[0014] The lipase is selected from at least one of Candida antarctica lipase and Bacillus subtilis lipase; and / or,

[0015] The esterase is selected from at least one of Thermomysin esterase, Bacillus caldovelox carboxylic acid esterase, Pseudomonas pseudoalcaligenes esterase, and Sphagnum centrale esterase; and / or,

[0016] The cutinase is selected from at least one of Thermomysin cutinase and Sphacelotheca reiliana cutinase.

[0017] According to the present application, the composite degradation promoter comprises:

[0018] The size of the microparticles can be adjusted according to the actually used degrading bacterial spores, for example, the particle size of the microparticles is 200-2000 nm, and preferably 500-1000 nm; and / or,

[0019] In the microparticles, the thickness of the shell layer is 5-100 nm, and preferably 10-50 nm.

[0020] The second aspect of the present application provides a preparation method of the composite degradation promoter, comprising the steps of loading halloysite with a degradation promoter and then coating degrading bacterial spores.

[0021] According to the present application, the preparation method of the composite degradation promoter comprises the following steps:

[0022] (1) dispersing halloysite in a degradation promoter solution to obtain halloysite loaded with a degradation promoter through physical adsorption;

[0023] (2) The halloysite-loaded degradation promoter is mixed with the degradation bacterial spore suspension and then co-incubated and coated to obtain the composite degradation promoter.

[0024] According to the present invention, in the preparation method of the composite degradation promoter:

[0025] In the degradation accelerator solution, the concentration of the degradation accelerator is 10–500 g / L; and / or,

[0026] The mass ratio of halloysite to degradation promoter is 1:10 to 10:1, preferably 1:5 to 5:1; and / or,

[0027] The OD of the degraded bacterial spore suspension 600 The value is 0.8 to 1.2; and / or,

[0028] The solvent for the degraded bacterial spore suspension is sterile deionized water; and / or,

[0029] The physical adsorption conditions in step (1) are: dispersion at 20–40°C and a vacuum degree below 0.1 MPa for 5–60 min, followed by restoration to normal pressure and standing for 5–30 min; and / or,

[0030] Step (1) further includes filtration and drying after dispersion. The filtration can employ common solid-liquid separation methods (e.g., centrifugation), and the drying can utilize common drying equipment and conditions, such as a drying temperature of 20–80°C; and / or,

[0031] The conditions for incubation and coating in step (2) are: stirring at 20–40°C and a speed of less than 500 rpm for 2–30 minutes; and / or,

[0032] The dispersion process in step (2) further includes filtration and drying. The filtration can be carried out using common solid-liquid separation methods (e.g., centrifugal separation), and the drying can be carried out using common drying equipment and drying conditions, such as a drying temperature of 20 to 80°C.

[0033] A third aspect of the present invention is to provide a controllable degradable polyester composite material, comprising polyester and a composite degradation accelerator, wherein the composite degradation accelerator is the composite degradation accelerator described above or the composite degradation accelerator obtained by the above preparation method.

[0034] According to the present invention, in the controllable degradable polyester composite material:

[0035] The polyester is selected from at least one of polybutylene terephthalate (PBAT), polylactic acid (PLA), polyhydroxyalkanoate (PHA), polycaprolactone (PCL), polypropylene carbonate (PPC), and polybutylene succinate (PBS); and / or,

[0036] Based on 100 parts by weight of the polyester, the composite degradation accelerator is 2 to 50 parts, preferably 10 to 30 parts.

[0037] The biodegradable polyester composite material provided by the present invention can control the biodegradation rate of the polyester composite material by adjusting the amount of composite degradation promoter therein. For example, the biodegradation rate of the biodegradable polyester composite material is 1 to 4 times that of polyester.

[0038] A fourth aspect of the present invention is to provide a method for preparing the above-mentioned controllable degradable polyester composite material, comprising the step of compounding the polyester with a composite degradation accelerator. The compounding method can employ common blending methods and blending process conditions, such as common melt blending, and the mixing equipment can be common extrusion, internal mixing, open milling, etc. Preferably, the compounding conditions are: temperature 70–210°C and time 3–15 min.

[0039] The technical solution provided by this invention has the following technical effects:

[0040] (1) The present invention uses halloysite to load degradation promoter to form a slow-release degradation promoter component, and then coats the degradation bacterial spores to form a core-shell structure to obtain a composite degradation promoter, which improves the thermal stability of the degradation bacterial spores, enabling them to be thermally processed with biodegradable polyester; through the synergistic effect of slow-release degradation promoter and degradation bacterial spores, the biodegradation rate of biodegradable materials is regulated.

[0041] (2) The present invention blends the composite degradation promoter with biodegradable polyester and controls the degradation rate by designing the loading rate, coating rate and raw material ratio, so that the biodegradation rate of the biodegradable material with controllable degradation rate is 1 to 4 times that of the original biodegradable polyester, which solves the problem of poor controllability of degradation rate of current biodegradable materials; the production process is simple and can be carried out on a large scale industrially by using existing biodegradable polyester modification production line. Attached Figure Description

[0042] Figure 1 a to b are the release-time curves of the slow-release degradation promoters a1 and b1 prepared in Examples 1 and 2, respectively.

[0043] Figure 2 a to c are the thermogravimetric analysis curves of the slow-release degradation promoters a1 to a3, b1 to b3, and c1 to c3 prepared in Examples 1 to 3, respectively.

[0044] Figure 3 a-b are transmission electron microscope images of Bacillus subtilis spores and the composite degradation promoter A1 prepared in Example 1, respectively.

[0045] Figure 4a ~c represents the biodegradation rate-time curves of the polyester composite materials prepared in Examples 6-12, the polyester composite materials prepared in Comparative Examples 1-3, and PBAT.

[0046] Figure 5 Biodegradation rate-time curves of the polyester composite materials prepared in Examples 6, 8, and 10 and the polyester composite material prepared in Comparative Example 1. Detailed Implementation

[0047] The present invention will now be described in detail with reference to specific embodiments. It should be noted that the following embodiments are only used to further illustrate the present invention and should not be construed as limiting the scope of protection of the present invention. Some non-essential improvements and adjustments made by those skilled in the art based on the content of the present invention are still within the scope of protection of the present invention.

[0048] Various exemplary embodiments of the present invention will now be described in detail. This detailed description should not be considered as a limitation of the present invention, but rather as a more detailed description of certain aspects, features, and embodiments of the present invention.

[0049] It should be understood that the terminology used in this invention is merely for describing particular embodiments and is not intended to limit the invention. Furthermore, with respect to numerical ranges in this invention, it should be understood that each intermediate value between the upper and lower limits of the range is also specifically disclosed. Every smaller range between any stated value or intermediate value within a stated range, and any other stated value or intermediate value within said range, is also included in this invention. The upper and lower limits of these smaller ranges may be independently included or excluded from the range.

[0050] Unless otherwise stated, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art. While only preferred methods and materials have been described herein, any methods and materials similar or equivalent to those described herein may be used in the implementation or testing of this invention. All references to this specification are incorporated by way of citation to disclose and describe methods and / or materials associated with those references. In the event of any conflict with any incorporated reference, the content of this specification shall prevail.

[0051] Various modifications and variations can be made to the specific embodiments described in this specification without departing from the scope or spirit of the invention, as will be apparent to those skilled in the art. Other embodiments derived from this specification will also be obvious to those skilled in the art. This application specification and embodiments are merely exemplary.

[0052] The terms “include,” “including,” “have,” “contain,” etc., used in this article are all open-ended terms, meaning that they include but are not limited to.

[0053] The raw materials used in the following embodiments of the present invention are sourced from the following sources:

[0054] Halloysite purity >98%, purchased from Guangdong Jina New Materials Technology Co., Ltd., inner tube diameter 20-50nm, length 500-1500nm;

[0055] Urea and sodium dihydrogen phosphate were both chemically pure and purchased from Fuchen Chemical Reagent Co., Ltd.

[0056] Antarctic Candida lipase B, biological grade, purchased from Novozymes (China) Biotechnology Co., Ltd.

[0057] Bacillus subtilis, Bacillus licheniformis spores, and Bacillus thermophilus were isolated and screened from compost using biodegradable polyester as the sole carbon source. Specifically, the surface of the biodegradable polyester film in the compost environment was washed with PBS to obtain a mixed bacterial solution, which was then inoculated onto a screening medium using biodegradable polyester as the sole carbon source and incubated at 37°C. Potential degrading bacterial colonies that grew on the medium were purified one by one using the streak plate method, and the obtained single strains were expanded and preserved.

[0058] Polybutylene terephthalate (PBAT), brand name Ecoworld, was purchased from Shanxi Jinhui Zhaolong High-tech Technology Co., Ltd.

[0059] The product characterization method used in this invention is as follows:

[0060] Ultraviolet-visible spectrophotometry (UV-vis): Performed on a Shimadzu UV3600 instrument, using the dimethylaminobenzaldehyde colorimetric method to detect urea concentration and directly detect sodium dihydrogen phosphate concentration.

[0061] Transmission electron microscopy (TEM): at Tecnai G 2 The procedure was performed on an instrument, with the sample dispersion droplets placed on a carbon support film.

[0062] Thermogravimetric analysis (TGA): performed on a TAQ50 instrument, with the temperature increased from 25°C to 500°C at a rate of 20°C / min under a nitrogen atmosphere.

[0063] Tensile property test: conducted according to GB / T 1040.3-2018 on a SANS CMT6104 instrument, at a test speed of 100 mm / min.

[0064] Tear resistance test: conducted according to QB / T 1130-1991 on a SANS CMT6104 instrument, at a test speed of 200 mm / min.

[0065] Biodegradation test: conducted in accordance with GB / T 22047-2008, the biodegradation rate was determined by measuring the oxygen demand in a closed respirometer.

[0066] Example 1: Preparation of Composite Degradation Accelerator

[0067] (1) Halloysite was uniformly dispersed in a 100 g / L urea aqueous solution, kept at room temperature and vacuum degree below 0.1 MPa for 30 min, then allowed to stand at normal pressure for 10 min, centrifuged, dried under vacuum at 60℃, and ground to obtain halloysite-supported degradation promoter HNT-N.

[0068] (2) Prepare a 50 g / L halloysite-loaded degradation accelerator solution by dissolving the halloysite-loaded degradation accelerator HNT-N prepared in step (1) in an equal volume of Bacillus subtilis spore suspension (OD). 600 =1) Stir the composite degradation promoter solution at room temperature for 5 minutes at 360 rpm, centrifuge, and dry under vacuum at 60℃ to obtain the composite degradation promoter BS@HNT-N.

[0069] Halloysite-loaded degradation promoter HNT-N was prepared according to step (1) with a mass ratio of halloysite to urea of ​​2:1, 1:1 and 1:2 respectively, and was denoted as slow-release degradation promoter a1, a2 and a3 respectively; composite degradation promoter BS@HNT-N was prepared according to step (2), and was denoted as composite degradation promoter A1, A2 and A3 respectively.

[0070] Example 2: Preparation of Composite Degradation Accelerator

[0071] In the preparation process of the composite degradation promoter BS@HNT-P, steps (1) to (2) are the same as in Example 1, except that the degradation promoter urea is replaced with sodium dihydrogen phosphate.

[0072] Halloysite-supported degradation promoter HNT-P was prepared according to step (1) with the mass ratio of halloysite to sodium dihydrogen phosphate being 2:1, 1:1 and 1:2 respectively, and was denoted as slow-release degradation promoters b1, b2 and b3 respectively; composite degradation promoters were prepared according to step (2), and were denoted as composite degradation promoters B1, B2 and B3 respectively.

[0073] Example 3: Preparation of Composite Degradation Accelerator

[0074] In the preparation of the composite degradation promoter BS@HNT-C, steps (1) to (2) are the same as in Example 1, except that the degradation promoter urea is replaced with Candida antarcticis lipase (CALB).

[0075] Halloysite-loaded degradation promoter HNT-C was prepared according to step (1) with the mass ratio of halloysite to CALB being 2:1, 1:1 and 1:2 respectively, and was denoted as slow-release degradation promoters c1, c2 and c3 respectively; composite degradation promoters were prepared according to step (2), and were denoted as composite degradation promoters C1, C2 and C3 respectively.

[0076] Test Example 1: Testing of Composite Degradation Accelerators

[0077] like Figure 1 As shown, the slow-release degradation promoters a1 and b1 (with a mass ratio of halloysite to degradation promoter of 2:1) prepared in Examples 1 and 2 slowly release degradation promoters in water, reaching complete release after 24 hours. This indicates that even in a good solvent for degradation promoters, the release process of degradation promoters can be significantly reduced by loading halloysite.

[0078] Figure 2 a to c are the thermogravimetric analysis curves of the slow-release degradation promoters a1 to a3, b1 to b3, and c1 to c3 prepared in Examples 1 to 3, respectively. Figure 2 As shown in a to c, the mass retention rate of the slow-release degradation promoters prepared in Examples 1 to 3 at 500°C gradually increased as the amount of halloysite decreased.

[0079] Table 1. Mass retention rate and loading rate of the slow-release degradation promoters in Examples 1-3

[0080]

[0081] Table 1 shows the mass retention rate (TG) and loading rate of the slow-release degradation promoters a1-a3, b1-b3, and c1-c3 prepared in Examples 1-3 at 500℃. As shown in Table 1, the loading rate of the slow-release degradation promoters a1-a3, b1-b3, and c1-c3 prepared in Examples 1-3 gradually increased with decreasing halloysite content, and the loading rate of the degradation promoters in halloysite ranged from 5% to 25%.

[0082] The enzyme activity of the slow-release degradation promoter C3 (halolite and CALB mass ratio of 1:1) prepared in Example 3 at a concentration of 10 mg / mL was determined using a lipase kit before and after heat treatment, along with the CALB enzyme solution. The enzyme activity of the slow-release degradation promoter prepared in Example 3 (calculated based on CALB in the slow-release degradation promoter) was 299.10 nmol / min / mL, and after heat treatment at 150°C for 5 min, the enzyme activity remained at 277.71 nmol / min / mL. The enzyme activity of CALB was 276.69 nmol / min / mL, and after heat treatment at 150°C for 5 min, the enzyme activity was 30.43 nmol / min / mL. This indicates that loading CALB with halloysite can improve thermal stability and protect enzyme activity.

[0083] Figure 3 a-b are transmission electron microscope images of Bacillus subtilis spores and the composite degradation promoter A1 (halolite and urea in a mass ratio of 2:1) prepared in Example 1, respectively. Figure 3 As shown in the TEM image of the composite degradation promoter prepared in Example 1, the smooth outer protein shell of the spore becomes rough and significantly thickened, indicating the core-shell structure of the composite degradation promoter BS@HNT-N.

[0084] Example 4: Preparation of Composite Degradation Accelerator

[0085] In the preparation process of the composite degradation promoter G@HNT-N, steps (1) to (2) are the same as in Example 1, except that the Bacillus subtilis spores are replaced with Bacillus licheniformis spores. The mass ratio of halloysite to Bacillus licheniformis spores is 1:1.

[0086] Example 5: Preparation of Composite Degradation Accelerator

[0087] In the preparation of the composite degradation promoter GK@HNT-N, steps (1) to (2) are the same as in Example 1, except that Bacillus subtilis spores are replaced with Bacillus thermophilus spores. The mass ratio of halloysite to Bacillus thermophilus spores is 1:1.

[0088] Example 6: Preparation of Controlled Degradable Polyester Composite Material

[0089] 100 parts of PBAT resin were added to a 135°C internal mixer and stirred at 90 rpm for 2 minutes until melted. Then, 30 parts of the composite degradation accelerator A1 prepared in Example 1 were added, and stirring was continued for 5 minutes. The product was then collected. After being crushed into granules and dried, the controllable degradable polyester composite material PBAT / BS@HNT-N was obtained.

[0090] Example 7: Preparation of Controlled Degradable Polyester Composite Material

[0091] The preparation method of the controllable degradable polyester composite material PBAT / BS@HNT-P is the same as that in Example 6, except that the composite degradation accelerator used is the composite degradation accelerator B1 prepared in Example 2.

[0092] Example 8: Preparation of Controlled Degradable Polyester Composite Material

[0093] The preparation method of the controllable degradable polyester composite material PBAT / BS@HNT-C is the same as that in Example 6, except that the composite degradation accelerator used is the composite degradation accelerator C3 prepared in Example 3.

[0094] Example 9: Preparation of Controlled Degradable Polyester Composite Material

[0095] The preparation method of the controllable degradable polyester composite material PBAT / G@HNT-N is the same as that in Example 6, except that the composite degradation promoter used is G@HNT-N prepared in Example 4.

[0096] Example 10: Preparation of Controlled Degradable Polyester Composite Material

[0097] The preparation method of the controllable degradable polyester composite material PBAT / GK@HNT-N is the same as that in Example 6, except that the composite degradation promoter used is GK@HNT-N prepared in Example 5.

[0098] Example 11 Preparation of Controlled Degradable Polyester Composite Material

[0099] The preparation method of the controllable degradable polyester composite material PBAT / BS@HNT-N is the same as in Example 6, except that the composite degradation accelerator used is 20 parts.

[0100] Example 12 Preparation of Controlled Degradable Polyester Composite Material

[0101] The preparation method of the controllable degradable polyester composite material PBAT / BS@HNT-N is the same as in Example 6, except that the composite degradation promoter used is 10 parts.

[0102] Comparative Example 1: Preparation of Biodegradable Materials

[0103] The preparation method of the biodegradable material PBAT / HNT is the same as in Example 6, except that halloysite is used instead of the composite degradation promoter.

[0104] Comparative Example 2: Preparation of Biodegradable Materials

[0105] The preparation method of the biodegradable material PBAT / HNT-N is the same as in Example 6, except that the slow-release degradation promoter a1 is used instead of the composite degradation promoter.

[0106] Comparative Example 3: Preparation of Biodegradable Materials

[0107] The preparation method of the biodegradable material PBAT / HNT-C is the same as in Example 6, except that the slow-release degradation promoter C3 is used instead of the composite degradation promoter.

[0108] Test Example 2: Testing of Controlled Degradable Polyester Composite Materials

[0109] The controllable degradable polyester composite materials prepared in Examples 6-12 and the biodegradable materials prepared in Comparative Examples 1-3 were extruded and blown into films. The screw processing temperature of the blown film device was 145°C, the die head temperature was 140°C, the screw length-to-diameter ratio was 20:1, and the blow-up ratio was 2:1. A uniform biodegradable film with a controllable degradation rate and a thickness of about 10 μm was obtained. The film was subjected to tensile property tests, tear property tests, and soil environmental degradation property tests.

[0110] As shown in Table 2, compared with PBAT film and biodegradable material films of Comparative Examples 1-3, the tear strength, tensile strength and elongation at break of the controllable degradable polyester composite materials prepared in Examples 6-10 did not show a significant decrease.

[0111] Table 2 Mechanical properties of biodegradable materials with controllable degradation rates

[0112]

[0113] Figure 4a ~c represents the biodegradation rate-time curves of the controllable degradable polyester composite materials prepared in Examples 6-12 and the biodegradable materials prepared in Comparative Examples 1-3. For example... Figure 4a As shown in Figures ~c, the degradation rates of the controllable degradable polyester composite films prepared in Examples 6-12 were significantly higher than those of the biodegradable films in Comparative Examples 1-3. After 90 days of degradation in the soil environment, compared with the halloysite composite PBAT film in Comparative Example 1, the biodegradability of the controllable degradable polyester composite films prepared in Examples 6-10 increased by 85.2%, 84.1%, 108.7%, 63.7%, and 55.4%, respectively; compared with the PBAT / HNT-N composite film in Comparative Example 2, the biodegradability of the controllable degradable polyester composite films prepared in Examples 6-10 increased by 56.9%, 56.0%, 76.8%, 38.7%, and 31.7%, respectively. After 90 days, the biodegradability of the controllable degradable polyester composite films prepared in Examples 6, 11, and 12 were 48.6%, 42.3%, and 39.9%, respectively, indicating that the composite degradation promoter can significantly promote the degradation of PBAT, and the greater the amount used, the more obvious the promoting effect on degradation.

[0114] The present invention has been described in detail above with reference to specific embodiments and exemplary examples. However, these descriptions should not be construed as limiting the present invention. Those skilled in the art can make various equivalent substitutions, modifications, or improvements to the technical solutions and embodiments of the present invention without departing from the spirit and scope of the invention, and all such modifications and improvements fall within the scope of the present invention. The protection scope of the present invention is not limited to the technical solutions described in the above specific embodiments; therefore, the foregoing descriptions are merely preferred options and are not restrictive.

Claims

1. A composite degradation promoter comprising core-shell structured microparticles, wherein the microparticles have a degradation spore as the core and an halloysite-loaded degradation promoter as the shell, wherein the degradation promoter is selected from at least one of nitrogen-containing compounds, phosphate compounds, lipases, esterases, and keratinases.

2. The composite degradation promoter according to claim 1, characterized in that, The degrading bacterial spores are selected from at least one of Bacillus subtilis spores, Bacillus licheniformis spores, Bacillus thermophilus, Bacillus brevis spores, Bacillus megaterium spores, Bacillus mucilaginosus spores, Bacillus azotocinus spores, and Bacillus spheroidosa spores; and / or The nitrogen-containing compound is selected from at least one of urea, ammonium sulfate, and ammonium bicarbonate, and / or the phosphate compound is selected from at least one of dipotassium hydrogen phosphate, potassium dihydrogen phosphate, disodium hydrogen phosphate, and sodium dihydrogen phosphate; and / or, The lipase is selected from at least one of Candida antarcticis lipase and Bacillus subtilis lipase; and / or The esterase is selected from at least one of thermophilic actinomycete esterase, thermophilic Bacillus carboxylesterase, Alcaligenes-like Pseudomonas esterase, and mesophyll esterase; and / or The keratinase is selected from at least one of thermophilic actinomycete keratinase and smut fungus keratinase.

3. The composite degradation promoter according to claim 1 or 2, characterized in that, The particle size is 200–2000 nm, preferably 500–1000 nm; and / or, The thickness of the shell in the microparticle is 5–100 nm, preferably 10–50 nm.

4. A method for preparing the composite degradation promoter according to any one of claims 1 to 3, comprising the step of loading halloysite with the degradation promoter and then coating it with degrading bacterial spores.

5. The method for preparing the composite degradation promoter according to claim 4, characterized in that, The preparation method of the composite degradation promoter includes the following steps: (1) Halloysite was dispersed in a degradation promoter solution and subjected to physical adsorption to obtain a halloysite-supported degradation promoter. (2) The halloysite-loaded degradation promoter is mixed with the degradation bacterial spore suspension and then co-incubated and coated to obtain the composite degradation promoter.

6. The method for preparing the composite degradation promoter according to claim 5, characterized in that, In the degradation accelerator solution, the concentration of the degradation accelerator is 10–500 g / L; and / or, The mass ratio of halloysite to degradation promoter is 1:10 to 10:1, preferably 1:5 to 5:1; and / or, The OD of the degraded bacterial spore suspension 600 The value is 0.8 to 1.2; and / or, The solvent for the degraded bacterial spore suspension is sterile deionized water; and / or, The physical adsorption conditions in step (1) are: dispersion at 20–40°C and a vacuum degree below 0.1 MPa for 5–60 min, followed by restoration to normal pressure and standing for 5–30 min; and / or, The dispersion process in step (1) further includes filtration and drying steps; and / or, The conditions for incubation and coating in step (2) are: stirring at 20–40°C and a speed of less than 500 rpm for 2–30 minutes; and / or, The dispersion process in step (2) also includes filtration and drying.

7. A controllable degradable polyester composite material, comprising polyester and a composite degradation accelerator, wherein the composite degradation accelerator is the composite degradation accelerator according to any one of claims 1 to 3 or the composite degradation accelerator obtained by the preparation method according to any one of claims 4 to 6.

8. The controllable degradable polyester composite material according to claim 7, characterized in that, The polyester is selected from at least one of polybutylene terephthalate, polylactic acid, polyhydroxyalkanoate, polycaprolactone, polypropylene carbonate, and polybutylene succinate; and / or, Based on 100 parts by weight of the polyester, the composite degradation accelerator is 2 to 50 parts, preferably 10 to 30 parts.

9. A method for preparing the controllable degradable polyester composite material according to any one of claims 7 or 8, comprising the step of compounding the polyester with a composite degradation promoter.

10. The method for preparing the controllable degradable polyester composite material according to claim 9, characterized in that, The conditions for the composite process are: temperature 70–210℃ and time 3–15 min.

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