Natural ecological biodegradable product and preparation method thereof

Abstract

The invention relates to the technical field of biodegradation, in particular to a natural ecological biodegradable product and a preparation method thereof. The natural ecological biodegradable product is prepared from the following raw materials in parts by mass: 50 to 60 parts of starch, 10 to 20 parts of cellulose fiber, 10 to 20 parts of polylactic acid, 1 to 5 parts of phytic acid, 1 to 2 parts of nano zinc oxide, 1 to 5 parts of mesoporous silica, 5 to 10 parts of plasticizer, 3 to 8 parts of compatilizer and 3 to 5 parts of nucleating agent. According to the invention, the mesoporous silica is adopted to load the Zn-phytic acid complex, so that nanoscale dispersion is realized, agglomeration during processing is avoided, crack propagation is hindered through a pinning effect, and surface active groups and starch enhance interface bonding through a hydrogen bond network and a physical anchoring effect, so that the mechanical property of a product is synergistically improved; on the premise of ensuring biodegradability, the mechanical tensile strength of the product is effectively improved, and the comprehensive performance of the product is ensured.

Description

Technical Field

[0001] The present invention relates to the technical field of biodegradation, and particularly relates to a natural ecological biodegradable product and a preparation method thereof. Background Art

[0002] Biodegradable materials based on renewable resources are regarded as the core breakthrough to solve the plastic pollution dilemma. Among them, starch-based materials have become one of the most promising alternative solutions due to their wide sources, low cost, excellent biocompatibility and other characteristics.

[0003] As a natural polymer polysaccharide, starch is rich in hydroxyl groups on its molecular chain and theoretically can form a three-dimensional network structure through plasticization modification. However, the existing starch-based degradable materials have exposed significant technical bottlenecks in the actual application process: in terms of mechanical properties, the tensile strength of pure starch materials is generally low and it is difficult to meet the mechanical strength requirements of the packaging material scenario; in terms of heat resistance, conventional starch-based products are prone to softening and deformation under high temperature conditions, severely restricting their application in packaging and other fields. More severely, there is often a negative correlation effect between the mechanical properties and heat resistance of the material. Although conventional plasticizers can improve the processing fluidity, they will cause a significant decrease in the glass transition temperature, forming a problem of "strength - heat resistance" being offset against each other.

[0004] At present, through blending modification, adding synthetic polymers such as polylactic acid (PLA) and polybutylene adipate / terephthalate (PBAT) can improve the mechanical properties, but excessive addition will destroy the complete biodegradable characteristics of the material. In the nano-composite reinforcement technology, it is difficult to control the dispersion uniformity of fillers such as montmorillonite and cellulose nanocrystals, which is prone to stress concentration defects and cannot simultaneously achieve the improvement of mechanical strength and the optimization of heat resistance while maintaining the biodegradable characteristics of the material.

[0005] Therefore, developing starch-based materials with high strength, high heat resistance and biodegradable characteristics has become a technical problem that the industry urgently needs to overcome. Summary of the Invention

[0006] The purpose of the present invention is to solve the disadvantages existing in the prior art, and to propose a natural ecological biodegradable product and a preparation method thereof.

[0007] A natural ecological biodegradable product, the raw materials of which include by mass: 50 - 60 parts of starch, 10 - 20 parts of cellulose fiber, 10 - 20 parts of polylactic acid, 1 - 5 parts of phytic acid, 1 - 2 parts of nano-zinc oxide, 1 - 5 parts of mesoporous silica, 5 - 10 parts of plasticizer, 3 - 8 parts of compatibilizer, and 3 - 5 parts of nucleating agent.

[0008] Preferably, the starch includes at least one of corn starch, tapioca starch, and potato starch.

[0009] Preferably, the cellulose fiber includes at least one of bamboo fiber, hemp fiber, and cotton fiber, and its length is 5-20 mm.

[0010] Preferably, the pore diameter of the mesoporous silica is 10-20 nm, and the specific surface area is 800-1200 m 2 / g.

[0011] Preferably, the plasticizer includes at least one of glycerol, tributyl citrate, and epoxidized soybean oil.

[0012] Preferably, the compatibilizer is maleic anhydride grafted polylactic acid.

[0013] Preferably, the nucleating agent is talcum powder or nano calcium carbonate.

[0014] The preparation method of the above natural ecological biodegradable product includes the following steps: S1. Dry the starch for 2-4 h, add the cellulose fiber and mix evenly to obtain a mixed fiber material; S2. Add phytic acid to water and stir evenly, add nano zinc oxide and ultrasonically treat for 10-20 min, adjust the system pH to 5-6, stir at 50-60 °C for 10-20 min, add mesoporous silica and ultrasonically treat for 10-20 min, centrifuge, wash, vacuum dry, and pulverize to obtain a modifier; S3. Dry the polylactic acid for 3-5 h, sequentially add the plasticizer, compatibilizer, and nucleating agent and mix for 5-10 min, add the mixed fiber material and continue to mix for 20-30 min to obtain a premix; Extrude the premix.

[0015] Preferably, in S2, the ultrasonic treatment frequency after adding nano zinc oxide is 30-40 kHz, and the ultrasonic treatment frequency after adding mesoporous silica is 30-40 kHz.

[0016] Preferably, in S3, the extrusion temperature is 180-200 °C. Beneficial effects

[0017] The purpose of the present invention is to provide a natural ecological biodegradable product, which not only has good biodegradability and can be quickly decomposed into harmless substances in the natural environment, but also has excellent mechanical strength and thermal stability, can meet the needs of various use scenarios, and has a relatively low production cost at the same time.

[0018] The present invention uses polylactic acid, starch, and cellulose fiber as the main raw materials. These raw materials all have good biodegradability and can be gradually decomposed into harmless substances such as water and carbon dioxide through the action of microorganisms in the natural environment, which is environmentally friendly. The addition of starch and cellulose fiber not only reduces costs but also improves the biodegradation rate of the product. At the same time, cellulose fiber can enhance the mechanical properties of the product, making it have good tensile strength, flexural strength, and impact toughness, and can be widely used in many fields such as packaging, agriculture, and disposable products.

[0019] The present invention utilizes the formation of a Zn-phytate complex by nano-zinc oxide and the phosphate group of phytic acid. The uncoordinated phosphate group or hydroxyl group forms a hydrogen bond network with PLA. When processed at high temperature, the hydrogen bonds are partially broken at high temperature, reducing the intermolecular force, lowering the melt viscosity, and enhancing the fluidity. After cooling, the hydrogen bond network is rebuilt to form a rigid network, improving the heat resistance of the product; while talc or nano-calcium carbonate is used as a nucleating agent to promote the crystallization of PLA, increasing the crystallinity and heat distortion temperature, and synergistically acting with the Zn-phytate complex to enhance the shape stability under high-temperature environments (such as microwave heating).

[0020] The present invention uses mesoporous silica to load the Zn-phytate complex to achieve nano-scale dispersion, avoid agglomeration during processing, and hinder crack propagation through the pinning effect. Moreover, its surface active groups enhance the interfacial bonding with starch through hydrogen bond network and physical anchoring, synergistically improving the mechanical properties of the product. On the premise of ensuring biodegradability, the mechanical tensile strength of the product is effectively improved, ensuring the comprehensive performance of the product. Description of the Drawings

[0021] Figure 1 It is a comparison chart of the tensile strength and notched impact strength of the products obtained in Example 5 and Comparative Examples 1-3.

[0022] Figure 2 It is a graph showing the change in carbon dioxide release of the product obtained in Example 5 as the test material, reference material, and blank container.

[0023] Figure 3 It is a graph showing the change in biodegradation rate of the product obtained in Example 5 as the test material and reference material in 156 days. Detailed Embodiments

[0024] The present invention will be further explained below with specific embodiments.

[0025] The brand of polylactic acid used below is Unitika, and the model is HV-6250H. Example 1

[0026] A natural ecological biodegradable product, whose raw materials include: 520g of cassava starch, 120g of flax fiber with a length of 5mm, 100g of polylactic acid, 10g of phytic acid, 10g of nano zinc oxide, 10g of mesoporous silica, 50g of glycerol, 30g of maleic anhydride grafted polylactic acid, and 30g of talcum powder.

[0027] The method for preparing the above-mentioned natural ecological biodegradable product comprises the following steps: S1, placing cassava starch in an oven at 80°C for 2 hours, adding hemp fiber and mixing evenly to obtain a mixed fiber material; S2, adding phytic acid to 100g of deionized water and stirring evenly, adding nano zinc oxide and ultrasonically treating for 10min, the ultrasonic frequency is 30kHz, adjusting the pH of the system to 5-6, stirring at a temperature of 50°C for 10min, adding mesoporous silica and ultrasonically treating for 10min, the ultrasonic frequency is 30kHz, centrifuging, washing, vacuum drying, and crushing to obtain a modifier; S3. Put the polylactic acid into a vacuum oven and dry it at 60°C for 3h. Then add glycerol, maleic anhydride grafted polylactic acid and talcum powder into a high-speed mixer in sequence and mix at a speed of 800r / min for 5min. Then add the mixed fiber material and continue mixing for 20min to obtain a premix. Add the premix into a twin-screw extruder for melt blending and extrusion at an extrusion temperature of 180°C and a screw speed of 100r / min, and press into sheets. Example 2

[0028] A natural ecological biodegradable product, whose raw materials include: 580g of potato starch, 200g of cotton fiber with a length of 20mm, 200g of polylactic acid, 50g of phytic acid, 20g of nano zinc oxide, 50g of mesoporous silica, 100g of tributyl citrate, 80g of maleic anhydride grafted polylactic acid, and 50g of nano calcium carbonate.

[0029] The method for preparing the above-mentioned natural ecological biodegradable product comprises the following steps: S1, placing potato starch in an oven at 100°C for 4 hours, adding cotton fiber and mixing evenly to obtain a mixed fiber material; S2, adding phytic acid to 200g of deionized water and stirring evenly, adding nano zinc oxide and ultrasonically treating for 20min, the ultrasonic frequency is 40kHz, adjusting the pH of the system to 5-6, stirring at 60°C for 20min, adding mesoporous silica and ultrasonically treating for 20min, the ultrasonic frequency is 40kHz, centrifuging, washing, vacuum drying, and crushing to obtain a modifier; S3. Feed the polylactic acid into a vacuum oven and dry it at 80 °C for 5 h. Then, add tributyl citrate, maleic anhydride grafted polylactic acid, and nano calcium carbonate into a high-speed mixer and mix them at a speed of 1200 r / min for 10 min. Add the mixed fiber material and continue to mix for 30 min to obtain a premix. Add the premix into a twin-screw extruder for melt blending and extrusion. The extrusion temperature is 200 °C, the screw speed is 300 r / min, and then press into sheets. Example 3

[0030] A natural ecological biodegradable product, the raw materials of which include: 520 g of corn starch, 120 g of bamboo fiber with a length of 15 mm, 170 g of polylactic acid, 20 g of phytic acid, 17 g of nano zinc oxide, 20 g of mesoporous silica, 90 g of epoxidized soybean oil, 40 g of maleic anhydride grafted polylactic acid, and 45 g of talcum powder.

[0031] The preparation method of the above natural ecological biodegradable product includes the following steps: S1. Feed the corn starch into an oven at 85 °C and process for 3.5 h, then add the bamboo fiber and mix evenly to obtain a mixed fiber material; S2. Add the phytic acid into 120 g of deionized water and stir evenly. Add nano zinc oxide and perform ultrasonic treatment for 17 min, with an ultrasonic frequency of 33 kHz. Adjust the pH of the system to 5 - 6, stir at 58 °C for 12 min, add mesoporous silica and perform ultrasonic treatment for 18 min, with an ultrasonic frequency of 33 kHz. Then, centrifuge, wash, dry in vacuum, and pulverize to obtain a modifier; S3. Feed the polylactic acid into a vacuum oven and dry it at 75 °C for 3.5 h. Then, add epoxidized soybean oil, maleic anhydride grafted polylactic acid, and talcum powder into a high-speed mixer and mix them at a speed of 1100 r / min for 7 min. Add the mixed fiber material and continue to mix for 28 min to obtain a premix. Add the premix into a twin-screw extruder for melt blending and extrusion. The extrusion temperature is 185 °C, the screw speed is 250 r / min, and then press into sheets. Example 4

[0032] A natural ecological biodegradable product, the raw materials of which include: 580 g of corn starch, 90 g each of hemp fiber and cotton fiber with a length of 10 mm, 130 g of polylactic acid, 40 g of phytic acid, 13 g of nano zinc oxide, 40 g of mesoporous silica, 70 g of glycerol, 60 g of maleic anhydride grafted polylactic acid, and 35 g of nano calcium carbonate.

[0033] The preparation method of the above natural ecological biodegradable product includes the following steps: S1. Feed the corn starch into an oven at 95 °C and process for 2.5 h, then add the hemp fiber and cotton fiber and mix evenly to obtain a mixed fiber material; S2. Add phytic acid to 180 g of deionized water and stir evenly. Then add nano-zinc oxide and perform ultrasonic treatment for 13 min at an ultrasonic frequency of 39 kHz. Adjust the pH of the system to 5 - 6, stir at a temperature of 52 °C for 18 min, add mesoporous silica and perform ultrasonic treatment for 12 min at an ultrasonic frequency of 39 kHz. Centrifuge, wash, dry in vacuum, and pulverize to obtain a modifier. S3. Send polylactic acid into a vacuum oven and dry it at a temperature of 65 °C for 4.5 h. Then add glycerol, maleic anhydride grafted polylactic acid, and nano-calcium carbonate into a high-speed mixer and mix at a speed of 900 r / min for 9 min. Add the mixed fiber material and continue to mix for 22 min to obtain a premix. Add the premix into a twin-screw extruder for melt blending and extrusion. The extrusion temperature is 195 °C, and the screw speed is 150 r / min. Press into sheets. Example 5

[0034] A natural ecological biodegradable product, the raw materials of which include: 550 g of corn starch, 100 g of bamboo fiber with a length of 12 mm, 50 g of hemp fiber with a length of 12 mm, 150 g of polylactic acid, 30 g of phytic acid, 15 g of nano-zinc oxide, 30 g of mesoporous silica, 40 g of tributyl citrate, 40 g of epoxidized soybean oil, 50 g of maleic anhydride grafted polylactic acid, and 40 g of talcum powder.

[0035] The preparation method of the above natural ecological biodegradable product includes the following steps: S1. Send corn starch into an oven at a temperature of 90 °C and process for 3 h. Add bamboo fiber and hemp fiber and mix evenly to obtain a mixed fiber material. S2. Add phytic acid to 150 g of deionized water and stir evenly. Then add nano-zinc oxide and perform ultrasonic treatment for 15 min at an ultrasonic frequency of 36 kHz. Adjust the pH of the system to 5 - 6, stir at a temperature of 55 °C for 15 min, add mesoporous silica and perform ultrasonic treatment for 15 min at an ultrasonic frequency of 36 kHz. Centrifuge, wash, dry in vacuum, and pulverize to obtain a modifier. S3. Send polylactic acid into a vacuum oven and dry it at a temperature of 70 °C for 4 h. Then add tributyl citrate, epoxidized soybean oil, maleic anhydride grafted polylactic acid, and talcum powder into a high-speed mixer and mix at a speed of 1000 r / min for 8 min. Add the mixed fiber material and continue to mix for 25 min to obtain a premix. Add the premix into a twin-screw extruder for melt blending and extrusion. The extrusion temperature is 190 °C, and the screw speed is 200 r / min. Press into sheets. Comparative Example 1

[0036] A natural ecological biodegradable product, the raw materials of which include: 550 g of corn starch, 100 g of bamboo fiber with a length of 12 mm, 50 g of hemp fiber with a length of 12 mm, 150 g of polylactic acid, 30 g of phytic acid, 15 g of nano zinc oxide, 30 g of mesoporous silica, 40 g of tributyl citrate, 40 g of epoxidized soybean oil, 50 g of maleic anhydride grafted polylactic acid, and 40 g of talcum powder.

[0037] The preparation method of the above natural ecological biodegradable product includes the following steps: S1. Send the corn starch into an oven at a temperature of 90 °C for 3 h, add the bamboo fiber and hemp fiber, and mix evenly to obtain a mixed fiber material; S2. Add phytic acid to 150 g of deionized water, stir evenly, add nano zinc oxide, and perform ultrasonic treatment for 15 min. The ultrasonic frequency is 36 kHz. Adjust the pH of the system to 5-6, stir at a temperature of 55 °C for 15 min, centrifuge, wash, vacuum dry, and pulverize to obtain a modifier; S3. Send the polylactic acid into a vacuum oven, dry it at a temperature of 70 °C for 4 h, sequentially add tributyl citrate, epoxidized soybean oil, mesoporous silica, maleic anhydride grafted polylactic acid, and talcum powder into a high-speed mixer, mix at a speed of 1000 r / min for 8 min, add the mixed fiber material and continue to mix for 25 min to obtain a premix; add the premix into a twin-screw extruder for melt blending and extrusion. The extrusion temperature is 190 °C, the screw speed is 200 r / min, and press into sheets. Comparative Example 2

[0038] A natural ecological biodegradable product, the raw materials of which include: 550 g of corn starch, 150 g of polylactic acid, 30 g of phytic acid, 15 g of nano zinc oxide, 30 g of mesoporous silica, 40 g of tributyl citrate, 40 g of epoxidized soybean oil, 50 g of maleic anhydride grafted polylactic acid, and 40 g of talcum powder.

[0039] The preparation method of the above natural ecological biodegradable product includes the following steps: S1. Send the corn starch into an oven at a temperature of 90 °C for 3 h; S2. Add phytic acid to 150 g of deionized water, stir evenly, add nano zinc oxide, and perform ultrasonic treatment for 15 min. The ultrasonic frequency is 36 kHz. Adjust the pH of the system to 5-6, stir at a temperature of 55 °C for 15 min, add mesoporous silica, and perform ultrasonic treatment for 15 min. The ultrasonic frequency is 36 kHz, centrifuge, wash, vacuum dry, and pulverize to obtain a modifier; S3. Feed the polylactic acid into a vacuum oven and dry it at 70 °C for 4 h. Then, sequentially add tributyl citrate, epoxidized soybean oil, maleic anhydride grafted polylactic acid, and talcum powder into a high-speed mixer and mix them at a speed of 1000 r / min for 8 min. Add the corn starch treated in the oven and continue to mix for 25 min to obtain a premix. Add the premix into a twin-screw extruder for melt blending and extrusion. The extrusion temperature is 190 °C, the screw speed is 200 r / min, and then press into sheets. Comparative Example 3

[0040] A natural ecological biodegradable product, whose raw materials include: 550 g of corn starch, 100 g of bamboo fibers with a length of 12 mm, 50 g of hemp fibers with a length of 12 mm, 150 g of polylactic acid, 30 g of phytic acid, 15 g of nano-zinc oxide, 30 g of mesoporous silica, 40 g of tributyl citrate, 40 g of epoxidized soybean oil, and 50 g of maleic anhydride grafted polylactic acid.

[0041] The preparation method of the above natural ecological biodegradable product includes the following steps: S1. Feed the corn starch into an oven at 90 °C and process for 3 h. Add the bamboo fibers and hemp fibers and mix evenly to obtain a mixed fiber material. S2. Add the phytic acid into 150 g of deionized water and stir evenly. Add the nano-zinc oxide and perform ultrasonic treatment for 15 min. The ultrasonic frequency is 36 kHz. Adjust the pH of the system to 5 - 6, stir at 55 °C for 15 min, add the mesoporous silica and perform ultrasonic treatment for 15 min. The ultrasonic frequency is 36 kHz. Then, centrifuge, wash, dry in vacuum, and pulverize to obtain a modifier. S3. Feed the polylactic acid into a vacuum oven and dry it at 70 °C for 4 h. Then, sequentially add tributyl citrate, epoxidized soybean oil, and maleic anhydride grafted polylactic acid into a high-speed mixer and mix them at a speed of 1000 r / min for 8 min. Add the mixed fiber material and continue to mix for 25 min to obtain a premix. Add the premix into a twin-screw extruder for melt blending and extrusion. The extrusion temperature is 190 °C, the screw speed is 200 r / min, and then press into sheets.

[0042] Refer to GB / T 1040.4 - 2006 Plastics - Determination of tensile properties - Part 4: Test conditions for isotropic and orthotropic fiber - reinforced composite materials to determine the tensile strength of the products obtained in Example 5 and Comparative Examples 1 - 3. Refer to GB / T 1043.1 - 2008 Plastics - Determination of Charpy impact properties - Part 1: Non - instrumented impact test to determine the notched impact strength of the products obtained in Example 5 and Comparative Examples 1 - 3.

[0043] As Figure 1As shown, the tensile strength and notched impact strength of the sheet obtained in Example 5 are the highest, and are significantly superior to those of Comparative Examples 1-3 by chi-square test.

[0044] The products obtained in Example 5 and Comparative Examples 1-3 were vacuum formed into lunch boxes.

[0045] The above lunch boxes were subjected to evaporation residue tests (water at 60°C for 2 h, 4% acetic acid at 60°C for 2 h, 65% ethanol at 20°C for 2 h, n-hexane at 20°C for 2 h), and the results were all ≤ 5 mg / L, meeting the corresponding standards.

[0046] The above lunch boxes were tested for heavy metals (calculated as Pb or As, 4% acetic acid at 60°C for 2 h), and the results showed no detection, meeting the corresponding standards.

[0047] The above lunch boxes were subjected to decolorization tests (wiped with ethanol solution (65 + 35), soaked in water at 60°C for 2 h, soaked in 4% acetic acid at 60°C for 2 h, soaked in 65% ethanol at 20°C for 2 h, soaked in n-hexane at 20°C for 2 h), and the results were all negative, meeting the corresponding standards.

[0048] The above lunch boxes were tested for olefin polymers (n-hexane extract, xylene extract), and the results all met the corresponding standards.

[0049] The above lunch boxes were subjected to performance tests, and the test results are shown in Table 1 below: Table 1 Performance tests of lunch boxes obtained in Example 5 and Comparative Examples 1-3

[0050] It can be seen from the test results that the products obtained in Example 5 are superior to those of Comparative Examples 1-3 in mechanical properties.

[0051] In view of the best mechanical properties of the products obtained in Example 5, the sheet obtained in Example 5 was used as the test material in this application, and thin-layer chromatography grade cellulose was used as the reference material. Referring to GB / T 19277.1-2011 Determination of the ultimate aerobic biodegradation ability of materials under controlled composting conditions - Method by measuring the evolved carbon dioxide - Part 1: General method, a 156-day compost degradation experiment was carried out (the dry weight ratio of compost to test material / reference material is about 6:1, and air with CO 2 removed was used for aeration treatment to ensure that the oxygen concentration discharged from each compost container was not less than 6%, and the test was carried out at 58 ± 2°C and in the dark; the CO 2 evolution was measured by titration).

[0052] Among them, the cumulative carbon dioxide release and biodegradation rate of the test material are shown in Table 2 below.

[0053] Table 2 Cumulative carbon dioxide release and biodegradation rate of the test material

[0054] In Table 2, (CO 2 ), B,mean is the average value of the cumulative amount of carbon dioxide released from the blank containers, with the unit of grams per container (g / container); (CO 2 ), t1 , (CO 2 ), t2 and (CO 2 ), t3 are respectively the cumulative amounts of carbon dioxide released from the compost containers containing the test mixtures in three parallel groups, with the unit of grams per container (g / container); (CO 2 ), t,mean is the average value of the cumulative amount of carbon dioxide released from the compost containers containing the test materials in three parallel groups of test materials, with the unit of grams per container (g / container); D t1 , D t2 and D t3 are respectively the biodegradation rates of three parallel groups of test materials; D t,mean is the average value of the biodegradation rates of three parallel groups of test materials.

[0055] As Figure 2 shown, the carbon dioxide release amount of the reference material no longer increases significantly around the 70th day and begins to maintain a small increase; however, the test material maintains a significant upward trend throughout 156 days, indicating that the product obtained by the present invention is continuously decomposed efficiently during the compost degradation experiment.

[0056] As Figure 3 shown, the biodegradation rate of the reference material is 74.60% on the 45th day and 93.20% on the 156th day; while the biodegradation rate of the test material is 84.80% on the 156th day, and the relative degradation rate on the 156th day reaches 91.00%, confirming that the product obtained by the present invention has good biodegradation performance.

[0057] The above is only the preferred specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Any person skilled in the art within the technical scope disclosed by the present invention, according to the technical solution of the present invention and its inventive concept, makes equivalent substitutions or changes, and should be covered within the protection scope of the present invention.

Claims

1. A natural ecological biodegradable product, characterized in that: The raw materials include, by weight: 50-60 parts of starch, 10-20 parts of cellulose fiber, 10-20 parts of polylactic acid, 1-5 parts of phytic acid, 1-2 parts of nano zinc oxide, 1-5 parts of mesoporous silicon dioxide, 5-10 parts of plasticizer, 3-8 parts of compatibilizer and 3-5 parts of nucleating agent.

2. The natural ecological biodegradable product according to claim 1, characterized in that: Starches include: At least one of corn starch, tapioca starch and potato starch.

3. The natural ecological biodegradable product according to claim 1, characterized in that: The cellulose fiber includes at least one of bamboo fiber, hemp fiber and cotton fiber, and has a length of 5-20 mm.

4. The natural ecological biodegradable product according to claim 1, characterized in that: The pore size of mesoporous silica is 10-20nm and the specific surface area is 800-1200m 2 / g.

5. The natural ecological biodegradable product according to claim 1, characterized in that: Plasticizers include: At least one of glycerol, tributyl citrate, and epoxidized soybean oil.

6. The natural ecological biodegradable product according to claim 1, characterized in that: The compatibilizer is maleic anhydride grafted polylactic acid.

7. The natural ecological biodegradable product according to claim 1, characterized in that: The nucleating agent is talcum powder or nano calcium carbonate.

8. A method for preparing the natural ecological biodegradable product according to any one of claims 1 to 7, characterized in that: The steps include: S1, drying starch for 2-4 hours, adding cellulose fiber and mixing evenly to obtain a mixed fiber material; S2, adding phytic acid to water and stirring evenly, adding nano zinc oxide and ultrasonically treating for 10-20 minutes, adjusting the pH of the system to 5-6, stirring at 50-60° C. for 10-20 minutes, adding mesoporous silica and ultrasonically treating for 10-20 minutes, centrifuging, washing, vacuum drying, and crushing to obtain a modifier; S3, drying the polylactic acid for 3-5 hours, adding a plasticizer, a compatibilizer, and a nucleating agent in sequence and mixing for 5-10 minutes, adding the mixed fiber material and continuing to mix for 20-30 minutes to obtain a premix; and extruding the premix.

9. The method for preparing the natural ecological biodegradable product according to claim 8, characterized in that: In S2, the ultrasonic treatment frequency is 30-40 kHz after adding nano zinc oxide, and the ultrasonic treatment frequency is 30-40 kHz after adding mesoporous silica.

10. The method for preparing the natural ecological biodegradable product according to claim 8, characterized in that: In S3, the extrusion temperature is 180-200°C.

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