阅读说明：本技术 一种淀粉基片材组合物及制备方法 (Starch-based sheet composition and preparation method thereof ) 是由 刘焱龙 李淑珍 任柏成 任鹏 于 2021-11-08 设计创作，主要内容包括：本发明提供了一种淀粉基片材组合物,由以下重量份原料组成：淀粉100份、纳米二氧化硅0.5～2份、可降解树脂50～200份、偶联剂2～10份、有机酸低聚物2～10份,所述有机酸低聚物由有机二元酸或多元酸、二元醇以及季戊四醇制备而成。本发明基于淀粉表面羟基的酯化反应,设计了具有特定链长的二元或多元有机酸共聚物,通过将有机酸接枝于淀粉表面进而破坏淀粉的结晶结构,提高了淀粉塑性,可以在不外加增塑剂的条件下,与可降解树脂共混复合,制备性能优异的低成本全降解改性树脂。该组合物中淀粉可均匀分布于基体树脂中,经挤压成片材后,所得制品高力学强度、高断裂伸长率。(The invention provides a starch-based sheet composition which is prepared from the following raw materials in parts by weight: 100 parts of starch, 0.5-2 parts of nano silicon dioxide, 50-200 parts of degradable resin, 2-10 parts of coupling agent and 2-10 parts of organic acid oligomer, wherein the organic acid oligomer is prepared from organic dibasic acid or polybasic acid, dihydric alcohol and pentaerythritol. According to the invention, based on the esterification reaction of hydroxyl on the surface of starch, a binary or polybasic organic acid copolymer with a specific chain length is designed, the organic acid is grafted on the surface of the starch to destroy the crystalline structure of the starch, so that the plasticity of the starch is improved, and the starch can be blended and compounded with degradable resin under the condition of not adding a plasticizer, so that the low-cost fully-degradable modified resin with excellent performance is prepared. The starch in the composition can be uniformly distributed in matrix resin, and after the composition is extruded into a sheet, the obtained product has high mechanical strength and high elongation at break.)

1. The starch-based sheet material composition is characterized by comprising the following raw materials in parts by weight:

starch 100 parts

0.5-2 parts of nano silicon dioxide

50-200 parts of degradable resin

2-10 parts of coupling agent

2-10 parts of organic acid oligomer, wherein the organic acid oligomer is prepared from organic dibasic acid or polybasic acid, dihydric alcohol and pentaerythritol.

2. The composition as claimed in claim 1, wherein the molar ratio of the organic dibasic acid or polybasic acid, the dihydric alcohol and the pentaerythritol is (1.2-1.5) to 1: 0.01.

3. The composition of claim 1, wherein the organic diacid or polyacid is selected from one or more of citric acid, malic acid, tartaric acid, oxalic acid, succinic acid, adipic acid;

the dihydric alcohol is one or more selected from ethylene glycol, 1, 3-propylene glycol, 1, 4-butanediol, polylactic acid polyalcohol, poly epsilon-caprolactone polyalcohol, diethylene glycol, neopentyl glycol and 2-methyl-1, 3-propylene glycol.

4. The composition according to claim 1, wherein the organic acid oligomer has a degree of polymerization of 2 to 10.

5. The composition as claimed in claim 1, wherein the starch is selected from one or more of corn starch, potato starch, wheat starch, tapioca starch.

6. The composition of claim 1, wherein the nanosilica has a diameter of 1 to 500 nm.

7. The composition according to claim 1, wherein the degradable resin is a synthetic degradable polyester material, preferably one or more of polylactic acid (PLA), adipic acid-terephthalic acid-butanediol copolymer (PBAT), polybutylene succinate (PBS), adipic acid-succinic acid-butanediol copolymer (PBSA), poly epsilon-caprolactone (PCL), Polyhydroxyalkanoate (PHA).

8. The composition as claimed in claim 1, wherein the coupling agent is a silane coupling agent or an aluminate coupling agent, one or more of titanate coupling agents, preferably gamma-aminopropyltriethoxysilane (KH550), gamma-glycidoxypropyldimethoxysilane (KH560), gamma- (methacryloyloxy) propyltrimethoxysilane, N- (beta-aminoethyl) -gamma-aminopropyltrimethoxysilane (KH792), N-beta- (aminoethyl) -gamma-aminopropylmethyldimethoxysilane (DL602), trimethyl aluminate, triisopropyl aluminate, tribenzyl aluminate, isopropyltris (dioctylpyrophosphate) titanate (KR-38S), bis (dioctyloxypyrophosphate) ethylene titanate (KR-238S).

9. The composition of claim 1, wherein the organic acid oligomer is prepared by a process comprising the steps of:

mixing organic dibasic acid or polybasic acid, dihydric alcohol and pentaerythritol, heating to react under stirring, and removing water generated by the reaction in vacuum to obtain the carboxyl-terminated organic acid oligomer.

10. A method of preparing a starch-based sheet composition according to any one of claims 1 to 9, comprising the steps of:

carrying out ball milling on starch, organic acid oligomer and nano silicon dioxide to obtain a mixture;

stirring and mixing the mixture at a high speed until the water content in the system is lower than 2%, adding degradable resin and a coupling agent, mixing and discharging;

extruding and granulating the product in a double-screw extruder, and then extruding a sheet in a sheet extruder to obtain the starch-based sheet composition.

Technical Field

The invention belongs to the technical field of materials, and particularly relates to a starch-based sheet composition and a preparation method thereof.

Background

The environmental protection degradation of polymer materials has become the main development trend of civil polymers, especially disposable polymers in the future. The aliphatic polyester-based polymer material has good degradation performance, but has high cost and is not favorable for large-scale popularization and application. Although the cost of degradation can be reduced by adding inorganic mineral fillers such as talc and calcium carbonate, the inorganic fillers are not decomposed into environmentally-friendly small molecular substances after degradation of the degradable polymers, and the influence on the surrounding environment is difficult to evaluate in a short time. The fully degradable resin based on natural polymer materials such as starch does not have the problems, and the natural polymer materials based on starch have wide application space as long as the problems of starch plasticization and compatibility with the polymer materials can be solved well.

Chinese patent 201210176317.1 discloses a composition for producing starch-based biodegradable sheets, which is composed of starch, titanium dioxide, coupling agent, lubricant, granularity polymerization inhibitor, plasticizer and polystyrene, and has faster degradation speed compared with inorganic filler by adding plasticized starch into non-degradable plastics such as polystyrene. Chinese patent 201110299003.6 discloses a calcium-plastic starch resin sheet, which comprises two steps, wherein the first step is mixing and plasticizing starch and glycerol, and the second step is compounding the plasticized starch with polyolefin resin, calcium carbonate and the like to prepare a corresponding composition. The calcium plastic starch resin sheet has higher bursting strength, tearing strength and compressive strength, can be subjected to chromatography printing, and cannot be completely degraded due to the non-degradable polyolefin material contained in the composition. Chinese patent 201210002785.7 discloses a method for making modified starch sheet, which comprises mixing natural starch material, catalytic modifier and additives in an internal mixer under a closed circulation environment, and stirring and refining to obtain dough-like modified starch briquette, wherein the additives may include calcium carbonate to enhance the mechanical strength of the natural starch material. And (3) carrying out casting extrusion treatment on the modified starch granules by using a casting machine to form a flaky modified starch sheet. The composite modified product of starch and calcium carbonate is prepared by the method, but the mechanical properties of the product are not explained and explained.

The core problem of starch plasticization is to destroy the crystalline structure of starch, so that the starch can be plasticized at a proper temperature and blended and extruded with conventional resin to prepare modified materials with different properties. The common plasticizer has the possibility of slow precipitation, so that the method for preparing the starch modified material with plasticity by adopting a non-plasticizer plasticizing method has very important significance.

Disclosure of Invention

In view of the above, the technical problem to be solved by the present invention is to provide a starch-based sheet composition and a preparation method thereof, wherein the starch-based sheet composition provided by the present invention has high mechanical strength and high elongation at break.

The invention provides a starch-based sheet composition which is prepared from the following raw materials in parts by weight:

starch 100 parts

0.5-2 parts of nano silicon dioxide

50-200 parts of degradable resin

2-10 parts of coupling agent

2-10 parts of organic acid oligomer, wherein the organic acid oligomer is prepared from organic dibasic acid or polybasic acid, dihydric alcohol and pentaerythritol.

Preferably, the molar ratio of the organic dibasic acid or polybasic acid to the dihydric alcohol to the pentaerythritol is (1.2-1.5): 1: 0.01.

Preferably, the organic dibasic acid or polybasic acid is selected from one or more of citric acid, malic acid, tartaric acid, oxalic acid, succinic acid and adipic acid;

the dihydric alcohol is one or more selected from ethylene glycol, 1, 3-propylene glycol, 1, 4-butanediol, polylactic acid polyalcohol, poly epsilon-caprolactone polyalcohol, diethylene glycol, neopentyl glycol and 2-methyl-1, 3-propylene glycol.

Preferably, the polymerization degree of the organic acid oligomer is 2 to 10.

Preferably, the starch is selected from one or more of corn starch, potato starch, wheat starch and tapioca starch.

Preferably, the diameter of the nano silicon dioxide is 1-500 nanometers.

Preferably, the degradable resin is a synthetic degradable polyester material, preferably one or more of polylactic acid (PLA), adipic acid-terephthalic acid-butanediol copolymer (PBAT), polybutylene succinate (PBS), adipic acid-succinic acid-butanediol copolymer (PBSA), poly epsilon-caprolactone (PCL), and Polyhydroxyalkanoate (PHA).

Preferably, the coupling agent is one or more of a silane coupling agent, an aluminate coupling agent and a titanate coupling agent, and is preferably gamma-aminopropyltriethoxysilane (KH550), gamma-glycidoxypropyldimethoxysilane (KH560), gamma- (methacryloyloxy) propyltrimethoxysilane, N- (beta-aminoethyl) -gamma-aminopropyltrimethoxysilane (KH792), N-beta- (aminoethyl) -gamma-aminopropylmethyldimethoxysilane (DL602), trimethyl aluminate, triisopropyl aluminate, tribenzyl aluminate, isopropyltris (dioctylpyrophosphate) titanate (KR-38S), bis (dioctylpyrophosphate) ethylene titanate (KR-238S).

Preferably, the preparation method of the organic acid oligomer comprises the following steps:

mixing organic dibasic acid or polybasic acid, dihydric alcohol and pentaerythritol, heating to react under stirring, and removing water generated by the reaction in vacuum to obtain the carboxyl-terminated organic acid oligomer.

The invention also provides a preparation method of the starch substrate sheet composition, which comprises the following steps:

carrying out ball milling on starch, organic acid oligomer and nano silicon dioxide to obtain a mixture;

stirring and mixing the mixture at a high speed until the water content in the system is lower than 2%, adding degradable resin and a coupling agent, mixing and discharging;

extruding and granulating the product in a double-screw extruder, and then extruding a sheet in a sheet extruder to obtain the starch-based sheet composition.

Compared with the prior art, the invention provides a starch-based sheet composition which is prepared from the following raw materials in parts by weight: 100 parts of starch, 0.5-2 parts of nano silicon dioxide, 50-200 parts of degradable resin, 2-10 parts of coupling agent and 2-10 parts of organic acid oligomer, wherein the organic acid oligomer is prepared from organic dibasic acid or polybasic acid, dihydric alcohol and pentaerythritol. According to the invention, based on the esterification reaction of hydroxyl on the surface of starch, a binary or polybasic organic acid copolymer with a specific chain length is designed, the organic acid is grafted on the surface of the starch to destroy the crystalline structure of the starch, so that the plasticity of the starch is improved, and the starch can be blended and compounded with degradable resin under the condition of not adding a plasticizer, so that the low-cost fully-degradable modified resin with excellent performance is prepared. The starch in the composition can be uniformly distributed in matrix resin, and after the composition is extruded into a sheet, the obtained product has high mechanical strength and high elongation at break.

Detailed Description

The invention provides a starch-based sheet composition which is prepared from the following raw materials in parts by weight:

starch 100 parts

0.5-2 parts of nano silicon dioxide

50-200 parts of degradable resin

2-10 parts of coupling agent

2-10 parts of organic acid oligomer, wherein the organic acid oligomer is prepared from organic dibasic acid or polybasic acid, dihydric alcohol and pentaerythritol.

The starch-based sheet composition provided by the invention comprises starch selected from one or more of corn starch, potato starch, wheat starch and cassava starch.

The starch-based sheet composition further comprises 0.5-2 parts of nano silicon dioxide, preferably 0.5, 1.0, 1.5, 2.0, or any value between 0.5-2 parts. The diameter of the nano silicon dioxide is 1-500 nanometers, preferably 1, 5, 10, 50, 100, 200, 300, 400, 500 or any value between 1-500 nanometers.

The starch-based sheet composition further comprises 50-200 parts of degradable resin, preferably 50, 60, 70, 80, 90, 100, 110, 120, 130, 140, 150, 160, 170, 180, 190, 200, or any value between 50-200 parts. In the invention, the degradable resin is a synthetic degradable polyester material, preferably one or more of polylactic acid (PLA), adipic acid-terephthalic acid-butanediol copolymer (PBAT), polybutylene succinate (PBS), adipic acid-succinic acid-butanediol copolymer (PBSA), poly epsilon-caprolactone (PCL) and Polyhydroxyalkanoate (PHA). Preferably one or more of PLA, PBS and PBAT, the relative amount of degradable resin is adjusted according to the requirements on the mechanical properties of the product.

The starch-based sheet composition further comprises 2-10 parts of a coupling agent, preferably 2, 3, 4, 5, 6, 7, 8, 9, 10, or any value between 2-10 parts. The coupling agent is one or more of silane coupling agent, aluminate coupling agent and titanate coupling agent, preferably gamma-aminopropyl triethoxysilane (KH550), gamma-glycidoxypropyl dimethoxysilane (KH560), gamma- (methacryloyloxy) propyl trimethoxysilane, N- (beta-aminoethyl) -gamma-aminopropyl trimethyl (ethyltrimethoxysilane) (KH792), N-beta- (aminoethyl) -gamma-aminopropyl methyldimethoxysilane (DL602), trimethyl aluminate, triisopropyl aluminate, tribenzyl aluminate, isopropyl tri (dioctylpyrophosphate) titanate (KR-38S) or bis (dioctylpyrophosphate) ethylene titanate (KR-238S). The coupling agent can improve the compatibility of the starch and the degradable resin and improve the overall mechanical property of the blend. Among them, an aluminate coupling agent is preferable, and triisopropyl aluminate is particularly preferable.

The starch-based sheet composition further comprises 2-10 parts of organic acid oligomer, preferably 2, 3, 4, 5, 6, 7, 8, 9, 10, or any value between 2-10 parts.

In the present invention, the organic acid oligomer is prepared from an organic dibasic acid or polybasic acid, a dihydric alcohol and pentaerythritol.

Preferably, the preparation method of the organic acid oligomer comprises the following steps:

mixing organic dibasic acid or polybasic acid, dihydric alcohol and pentaerythritol, heating to react under stirring, and removing water generated by the reaction in vacuum to obtain the carboxyl-terminated organic acid oligomer.

Firstly, mixing organic dibasic acid or polybasic acid, dihydric alcohol and pentaerythritol in a reaction kettle to obtain a mixture.

Wherein the molar ratio of the organic dibasic acid or polybasic acid to the dihydric alcohol to the pentaerythritol is (1.2-1.5): 1:0.01, preferably 1.2:1:0.01, 1.3:1:0.01, 1.4:1:0.01, 1.5:1:0.01, or any value between (1.2-1.5): 1: 0.01.

The organic binary acid or the polybasic acid is selected from one or more of citric acid, malic acid, tartaric acid, oxalic acid, succinic acid and adipic acid;

the dihydric alcohol is one or more selected from ethylene glycol, 1, 3-propylene glycol, 1, 4-butanediol, polylactic acid polyalcohol, poly epsilon-caprolactone polyalcohol, diethylene glycol, neopentyl glycol and 2-methyl-1, 3-propylene glycol.

m＝10～20、n＝10～20

m＝10～20、n＝10～20

Wherein, the organic dibasic acid or polybasic acid is preferably citric acid or succinic acid; the diol is preferably 1, 4-butanediol, a polylactic acid polyol or a polyepsilon caprolactone polyol.

Then, the mixture is heated and reacted under the condition of stirring to obtain a reactant.

Wherein the reaction temperature is 90-150 ℃, preferably 90, 100, 110, 120, 130, 140, 150, or any value between 90-150 ℃, and the reaction time is 30-60 minutes, preferably 30, 40, 50, 60, or any value between 30-60 minutes.

Next, water produced by the reaction was removed in vacuo to give a carboxyl-terminated organic acid oligomer.

Wherein the polymerization degree of the organic acid oligomer is 2-10, preferably any value between 2, 3, 4, 5, 6, 7, 8, 9, 10, or 2-10 parts.

The invention also provides a preparation method of the starch substrate sheet composition, which comprises the following steps:

carrying out ball milling on starch, organic acid oligomer and nano silicon dioxide, and discharging to obtain a mixture;

stirring and mixing the mixture at a high speed until the water content in the system is lower than 2%, adding degradable resin and a coupling agent, mixing and discharging;

extruding and granulating the product in a double-screw extruder, and then extruding a sheet in a sheet extruder to obtain the starch-based sheet composition.

Firstly, carrying out ball milling on starch, organic acid oligomer and nano silicon dioxide, wherein the ball milling time is 30-120 min, preferably 30, 40, 50, 60, 70, 80, 90, 100, 110, 120 or any value between 30-120 min.

Discharging after ball milling is finished to obtain a mixture, and then stirring and mixing the mixture at a high speed until the water content in the system is lower than 2%, wherein the high-speed stirring is carried out in a high-speed stirrer, and the stirring temperature is 80-120 ℃, preferably 80, 90, 100, 110, 120, or any value between 80-120 ℃; the stirring time is 15-45 minutes, preferably 15, 20, 25, 30, 35, 40, 45 or any value between 15-45 minutes.

When the water content in the system is lower than 2%, adding the degradable resin and the coupling agent for mixing, wherein the mixing temperature is 80-120 ℃, and preferably any value between 80, 90, 100, 110 and 120, or between 80 and 120 ℃.

After the mixing is completed, the obtained product is granulated and then a sheet is extruded in a sheet extruder to obtain the starch-based sheet composition.

In the invention, a twin-screw extruder is preferably adopted for extrusion granulation at 130-180 ℃, and the extrusion granulation temperature is preferably 130, 140, 150, 160, 170, 180 or any value between 130-180 ℃.

The temperature of the extruded sheet in the sheet extruder is 145-180 ℃, and preferably 150-170 ℃.

According to the invention, based on the esterification reaction of hydroxyl on the surface of starch, a binary or polybasic organic acid copolymer with a specific chain length is designed, the organic acid is grafted on the surface of the starch to destroy the crystalline structure of the starch, so that the plasticity of the starch is improved, and the starch can be blended and compounded with degradable resin under the condition of not adding a plasticizer, so that the low-cost fully-degradable modified resin with excellent performance is prepared. The starch in the composition can be uniformly distributed in matrix resin, and after the composition is extruded into a sheet, the obtained product has high mechanical strength and high elongation at break.

In the invention, the starch substrate composition can be used for preparing full-degradable plastic products, and the products have good strength and toughness and can be used for replacing PP and PS plastic products.

For further understanding of the present invention, the starch-based sheet composition and the preparation method thereof provided by the present invention are illustrated below with reference to the following examples, and the scope of the present invention is not limited by the following examples.

Comparative example 1

100 parts of corn starch and 1 part of coupling agent trimethyl aluminate are mixed in a high-speed stirrer at 120 ℃ for 40 minutes under the condition of 500 revolutions/minute until the water content is lower than 2 percent, 150 parts of polylactic acid and 50 parts of PBAT are added and mixed for 1 minute, and after discharging and cooling to room temperature, the mixture is added into a double-screw extruder and extruded and granulated at 170 ℃. The obtained particles are blown into a film at 160 ℃ in an injection molding machine, the mechanical property of the film is tested, and the result is shown in the attached table 1.

Comparative example 2

100 parts of corn starch and 30 parts of plasticizer glycerol are mixed for 40 minutes at 110 ℃ in a high-speed mixer under the condition of 1000 revolutions per minute until the water content is lower than 2 percent, 200 parts of PLA is added and mixed for 1 minute, the mixture is cooled to room temperature after discharging, and then the mixture is added into a double-screw extruder and extruded and granulated at 150 ℃. The particles were extruded into sheets at 150 ℃ in an extruder, and the mechanical properties of the samples were tested, with the results shown in Table 1.

Preparation example 1

In a reaction kettle provided with a stirring device and a thermometer, mixing the raw materials in a molar ratio of 1.5:1:0.01 respectively adding citric acid, 1, 4-butanediol and pentaerythritol, heating to 150 ℃, reacting for 30 minutes, distilling under reduced pressure to remove water as a reaction by-product, and discharging the product out of the reaction kettle to obtain an organic acid oligomer A with the polymerization degree of 100-200 for later use.

Preparation example 2

In a reaction kettle provided with a stirring device and a thermometer, mixing the raw materials in a molar ratio of 1.2:1:0.01 respectively adding malic acid, neopentyl glycol and pentaerythritol, heating to 90 ℃, reacting for 60 minutes, distilling under reduced pressure to remove water as a reaction by-product, and discharging a product out of the reaction kettle to obtain an organic acid oligomer B with the polymerization degree of 100-150 for later use.

Preparation example 3

Tartaric acid, poly-epsilon-caprolactone polyol (with the polymerization degree of 8-12) and pentaerythritol are respectively added into a reaction kettle with a stirring device and a thermometer according to the molar ratio of 1.3:1:0.1, the temperature is raised to 125 ℃, the reaction lasts for 45 minutes, water as a reaction by-product is removed by distillation under reduced pressure, and the product is discharged out of the reaction kettle to obtain organic acid oligomer C with the polymerization degree of 100-150 for later use.

Comparative example 3

In a reaction kettle provided with a stirring device and a thermometer, mixing the raw materials in a molar ratio of 1.2:1:0.01 respectively adding malic acid, neopentyl glycol and polyethylene glycol 400, heating to 90 ℃, reacting for 60 minutes, distilling under reduced pressure to remove water as a reaction by-product, and discharging the product out of the reaction kettle to obtain the organic acid oligomer D. And (3) ball-milling 100 parts of corn starch and 2 parts of organic acid oligomer in a ball mill for 120 minutes, and discharging. Then transferring the mixture into a high stirring machine, mixing the mixture for 45 minutes at 80 ℃ until the water content in the system is lower than 2 percent, adding 50 parts of degradable resin PLA and 5502 parts of silane coupling agent, mixing the mixture for 1 minute at 80 ℃, and discharging the mixture. The obtained product is extruded and granulated at 130 ℃ in a double-screw extruder, sheets are extruded at 150 ℃ in a sheet extruder, and the mechanical property of the sample is tested, and the result is shown in the attached table 1.

Example 1

100 parts of corn starch, 2 parts of organic acid oligomer A and 2 parts of silicon dioxide are ball-milled in a ball mill for 120 minutes, and then the material is discharged. Then transferring the mixture into a high stirring machine, mixing the mixture for 45 minutes at 80 ℃ until the water content in the system is lower than 2 percent, adding 50 parts of degradable resin PLA and 5502 parts of silane coupling agent, mixing the mixture for 1 minute at 80 ℃, and discharging the mixture. The obtained product is extruded and granulated at 130 ℃ in a double-screw extruder, sheets are extruded at 150 ℃ in a sheet extruder, and the mechanical property of the sample is tested, and the result is shown in the attached table 1.

Example 2

100 parts of corn starch, 5 parts of organic acid oligomer B and 1 part of silicon dioxide are ball-milled in a ball mill for 60 minutes, and then the material is discharged. And then transferring the mixture into a high stirring machine, mixing the mixture for 30 minutes at 100 ℃ until the water content in the system is lower than 2%, adding 50 parts of degradable resin PLA 150 and PBAT and 5 parts of titanate coupling agent KR-38S, mixing the mixture for 1 minute at 100 ℃, and discharging the mixture. The obtained product is extruded and granulated at 150 ℃ in a double-screw extruder, sheets are extruded at 150 ℃ in a sheet extruder, and the mechanical property of the sample is tested, and the result is shown in the attached table 1.

Example 3

100 parts of corn starch, 10 parts of organic acid oligomer C and 2 parts of silicon dioxide are ball-milled in a ball mill for 30 minutes, and then the material is discharged. And transferring the mixture to a high stirring machine, mixing the mixture for 15 minutes at 120 ℃ until the water content in the system is lower than 2%, adding 120 parts of degradable resin PCL, 30 parts of PLA and 10 parts of triisopropyl aluminate, mixing the mixture for 1 minute at 120 ℃, and discharging the mixture. The obtained product is extruded and granulated at 180 ℃ in a double-screw extruder, sheets are extruded at 180 ℃ in a sheet extruder, and mechanical property tests are carried out on the samples, and the results are shown in attached table 1.

Example 4

100 parts of corn starch, 5 parts of organic acid oligomer A and 2 parts of silicon dioxide are ball-milled in a ball mill for 40 minutes, and then the material is discharged. And then transferring the mixture to a high stirring machine, mixing the mixture for 40 minutes at 90 ℃ until the water content in the system is lower than 2%, adding 130 parts of degradable resin PHA, 20 parts of PBSA, 3 parts of triisopropyl aluminate and 2 parts of titanate coupling agent KR-238S, mixing the mixture for 1 minute at 90 ℃, and then discharging the mixture. The obtained product is extruded and granulated at 175 ℃ in a double-screw extruder, a sheet is extruded at 170 ℃ in a sheet extruder, and the mechanical property of the sample is tested, and the result is shown in the attached table 1.

Example 5

100 parts of corn starch, 8 parts of organic acid oligomer B and 1 part of silicon dioxide are ball-milled in a ball mill for 90 minutes, and then the material is discharged. And then transferring the mixture to a high stirring machine, mixing the mixture for 40 minutes at 110 ℃ until the water content in the system is lower than 2%, adding 100 parts of degradable resin PLA, 20 parts of PCL, 1 part of trimethyl aluminate and 1 part of titanate coupling agent KR-38S, and mixing the mixture for 1 minute at 110 ℃ and then discharging the mixture. The obtained product is extruded and granulated in a double-screw extruder at 145 ℃. The sheets were extruded at 150 ℃ in a sheet extruder and the samples were tested for mechanical properties, the results are shown in Table 1.

Example 6

100 parts of corn starch, 6 parts of organic acid oligomer C and 1 part of silicon dioxide are ball-milled in a ball mill for 110 minutes, and then the material is discharged. And then transferring the mixture to a high stirring machine, mixing the mixture for 40 minutes at 100 ℃ until the water content in the system is lower than 2%, adding 60 parts of degradable resin PLA, 10 parts of PBSA, 120 parts of PBAT and 2 parts of triisopropyl aluminate, mixing the mixture for 1 minute at 100 ℃, and then discharging the mixture. The obtained product is extruded and granulated in a double-screw extruder at 155 ℃. The sheets were extruded at 150 ℃ in a sheet extruder and the samples were tested for mechanical properties, the results are shown in Table 1.

The mechanical property test results of the samples of the comparative example and the example are shown in the attached table 1.

The foregoing is only a preferred embodiment of the present invention, and it should be noted that, for those skilled in the art, various modifications and decorations can be made without departing from the principle of the present invention, and these modifications and decorations should also be regarded as the protection scope of the present invention.