A biobased degradable pp material and a preparation method thereof

Abstract

This invention discloses a bio-based biodegradable PP material and its preparation method. The following raw materials are weighed in parts by weight: 80-100 parts of PP masterbatch, 20-30 parts of modified polylactic acid, 5-10 parts of aminated cellulose, 1-2 parts of 4-dimethylaminopyridine, and 0.3-0.5 parts of benzoyl peroxide. The mixture is melt-extruded to obtain the bio-based biodegradable PP material. During the raw material blending process, the double bonds on the modified polylactic acid are linked to the PP molecules under the action of benzoyl peroxide, forming a network structure with the polysiloxane segments on the modified polylactic acid. The polylactic acid segments of the side chains of the polysiloxane segments are free in the gaps of the network, forming a semi-interpenetrating network structure, thereby increasing the mechanical properties of the material. Furthermore, the aminated cellulose can react with the aldehyde groups on the modified polylactic acid to form an imine structure, which, in combination with the borate ester on the modified polylactic acid, can increase the toughness of the material. This makes the PP material biodegradable while having excellent mechanical properties.

Description

Technical Field

[0001] This invention relates to the field of biodegradable PP material preparation technology, specifically to a bio-based biodegradable PP material and its preparation method. Background Technology

[0002] Polypropylene (PP) is a high-performance thermoplastic synthetic resin with excellent chemical resistance, heat resistance, electrical insulation, high mechanical strength, and abrasion resistance, making it widely used in clothing, automobiles, and chemicals. However, PP is a fossil fuel-derived product and is non-degradable, posing a significant environmental hazard. Therefore, there is an urgent need to develop a biodegradable PP material. By composite modification of polylactic acid (PLA) with PP, the overall performance of the material can be effectively improved, giving it both excellent mechanical properties and environmental benefits. This is a commonly used method for preparing biodegradable PP materials. However, the excessive brittleness of PLA results in poor impact resistance in the prepared composite material, making it prone to breakage under external forces, thus affecting its normal use. Summary of the Invention

[0003] The purpose of this invention is to provide a bio-based biodegradable PP material and its preparation method, which solves the problem of poor mechanical properties and easy breakage of polylactic acid modified PP materials at present.

[0004] The objective of this invention can be achieved through the following technical solutions:

[0005] A method for preparing a bio-based biodegradable PP material specifically includes the following steps:

[0006] Step A1: Mix the modified polysiloxane, modifier, and DMF evenly, and react for 3-5 hours at a speed of 150-200 r / min, a temperature of 40-50℃, and a pH of 11-12 to obtain the modified additive. Mix the modified additive, lactide, and DMF evenly, purge with nitrogen, and stir while adding stannous octoate at a speed of 120-150 r / min and a temperature of 120-130℃. Heat to 140-150℃ and react for 8-10 hours at a pressure of 6000 Pa to obtain the modified polylactic acid.

[0007] Step A2: Mix cellulose and N,N-dimethylacetamide evenly, purge with nitrogen, stir and add lithium chloride at a speed of 120-150 r / min and a temperature of 100-105℃ for 2-3 hours, then cool to 8-10℃, add triethylamine and p-toluenesulfonyl chloride, and react for 20-25 hours to obtain pretreated cellulose. Mix the pretreated cellulose, N,N-dimethylacetamide and ammonia evenly, and react for 20-25 hours at a temperature of 140-145℃ and a pressure of 2.5-2.8 MPa to obtain aminated cellulose.

[0008] Step A3: Weigh the following raw materials in parts by weight: 80-100 parts of PP masterbatch, 20-30 parts of modified polylactic acid, 5-10 parts of amino cellulose, 1-2 parts of 4-dimethylaminopyridine and 0.3-0.5 parts of benzoyl peroxide. Add the raw materials to a twin-screw extruder and melt-extrude them at the following temperatures: 140-150℃ in the feeding section, 180-190℃ in the melting section, 195℃ in the homogenization section, and 140-150℃ in the die section, to obtain bio-based biodegradable PP material.

[0009] Furthermore, in step A1, the molar ratio of amino groups on the modified polysiloxane to the modifier is 1:1, the mass ratio of the modifier to lactide is 1:4, and the amount of stannous octoate is 2% of the mass of the modifier.

[0010] Furthermore, in step A2, the ratio of cellulose, N,N-dimethylacetamide, lithium chloride, triethylamine, and p-toluenesulfonyl chloride is 2g:50mL:5.5g:6mL:125mmol, the ratio of pretreated cellulose to ammonia is 1.5g:20mL, and the mass fraction of ammonia is 25%.

[0011] Furthermore, the modified polysiloxane is prepared by the following steps:

[0012] Step B1: Tetramethylcyclotetrasiloxane, styrene, chloroplatinic acid and DMF are mixed evenly, and nitrogen gas is introduced for protection. The reaction is carried out for 6-8 hours at a rotation speed of 200-300 r / min and a temperature of 70-80℃ to obtain the pretreated monomer. The pretreated monomer, silver nitrite, 2,2,6,6-tetramethylpiperidine oxide, sodium bromide and DMF are mixed evenly, and nitrogen gas is introduced for protection. The reaction is carried out for 2-4 hours at a rotation speed of 60-80 r / min and a temperature of 35-40℃ to obtain the modified monomer.

[0013] Step B2: Lithium dimethylvinylsilane and tetrahydrofuran are mixed and protected with nitrogen. Under the conditions of 120-150 r / min and 25-30℃, the modified monomer is added while stirring. After reacting for 6-8 h, tetrachlorosilane is added and the reaction is continued for 1-1.5 h to obtain pretreated polysiloxane. The pretreated polysiloxane, palladium on carbon catalyst and DMF are mixed evenly and hydrogen is introduced to a pressure of 0.3-0.5 MPa. Under the conditions of 60-80 r / min and 80-85℃, the reaction is carried out for 4-5 h to obtain modified polysiloxane.

[0014] Furthermore, in step B1, the molar ratio of tetramethylcyclotetrasiloxane to styrene is 1:4, the amount of chloroplatinic acid is 1‰ of the mass of styrene, and the ratio of the amount of pretreatment monomer, silver nitrite, 2,2,6,6-tetramethylpiperidine oxide, sodium bromide and DMF is 100mmol:120mmol:10mmol:1mmol:200mL.

[0015] Furthermore, in step B2, the molar ratio of lithium dimethylvinylsilane, modified monomer, and tetrachlorosilane is 2:8:1, and the amount of palladium catalyst on carbon is 5% of the mass of the pretreated polysiloxane.

[0016] Furthermore, the modifier is prepared by the following steps:

[0017] 3,4-Dihydroxybenzoic acid, glycidol, p-toluenesulfonic acid, and toluene were mixed evenly and reacted at a speed of 120-150 r / min and a temperature of 115-120℃ for 2-3 hours to obtain an intermediate. The intermediate, 4-formylphenylboronic acid, and DMF were mixed evenly and reacted under nitrogen protection at a speed of 200-300 r / min, a temperature of 35-40℃, and a pH of 8.5-9 for 4-6 hours to obtain a modifier.

[0018] Furthermore, the molar ratio of 3,4-dihydroxybenzoic acid and glycidol is 1:1, the amount of p-toluenesulfonic acid is 2% of the mass of 3,4-dihydroxybenzoic acid and glycidol, and the molar ratio of the intermediate and 4-formylphenylboronic acid is 1:1.

[0019] The beneficial effects of this invention are as follows: A bio-based biodegradable PP material disclosed in this application includes the following raw materials: PP masterbatch, modified polylactic acid, amino-modified cellulose, 4-dimethylaminopyridine, and benzoyl peroxide. The modified polylactic acid is prepared by reacting modified polysiloxane and a modifier under alkaline conditions, so that the amino groups on the modified polysiloxane and the epoxy groups on the modifier react to obtain a modified additive. The modified additive is then reacted with lactide, using the modified additive as the reaction starting point, to form polylactic acid segments on the modified additive molecule, thereby obtaining modified polylactic acid.

[0020] Cellulose was activated with lithium chloride and then reacted with p-toluenesulfonyl chloride to form cellulose p-toluenesulfonate, thus obtaining pretreated cellulose. The pretreated cellulose was then aminated with ammonia to obtain aminated cellulose.

[0021] Modified polysiloxanes are prepared by reacting the Si-H bonds on tetramethylcyclotetrasiloxane and the double bonds on styrene with chloroplatinic acid to obtain a pretreated monomer. The pretreated monomer is then nitrated with silver nitrite and 2,2,6,6-tetramethylpiperidine oxide to form a nitro group at the para position of the benzene ring, thus obtaining a modified monomer. Using lithium dimethylvinylsilanolate as an initiator, the modified monomer undergoes ring-opening polymerization, followed by end-capping with tetrachlorosilane to obtain the pretreated polysiloxane. Finally, the pretreated polysiloxane is reduced with a palladium-on-carbon catalyst under a hydrogen atmosphere to convert the nitro group into an amino group, thus obtaining the modified polysiloxane.

[0022] The modifier is prepared by esterifying the carboxyl group on 3,4-dihydroxybenzoic acid and the hydroxyl group on glycidol under the action of p-toluenesulfonic acid to obtain an intermediate. The intermediate is then reacted with 4-formylphenylboronic acid to react the catechol on the intermediate with the borate group of 4-formylphenylboronic acid to form a borate ester structure, thus obtaining the modifier.

[0023] During the raw material blending process, the double bonds on the modified polylactic acid (PLA) are linked to the PP molecules under the action of benzoyl peroxide, thereby forming a network structure with the polysiloxane segments on the modified PLA. The PLA segments of the side chains of the polysiloxane segments are free in the gaps of the network, forming a semi-interpenetrating network structure, which increases the mechanical properties of the material. Furthermore, the amino-modified cellulose can react with the aldehyde groups on the modified PLA to form an imine structure, which, together with the borate ester on the modified PLA, can increase the toughness of the material. At the same time, the addition of cellulose further enhances the mechanical properties of the material, making the PP material biodegradable while possessing excellent mechanical properties. Detailed Implementation

[0024] The technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0025] Example 1: A method for preparing a bio-based biodegradable PP material, specifically including the following steps:

[0026] Step A1: Mix the modified polysiloxane, modifier and DMF evenly, and react for 3 hours at a speed of 150 r / min, a temperature of 40℃ and a pH of 11 to obtain the modified additive. Mix the modified additive, lactide and DMF evenly, purge with nitrogen, stir and add stannous octoate at a speed of 120 r / min and a temperature of 120℃, raise the temperature to 140℃ and react for 8 hours at a pressure of 6000 Pa to obtain the modified polylactic acid.

[0027] Step A2: Mix cellulose and N,N-dimethylacetamide evenly, purge with nitrogen, stir and add lithium chloride at 120 r / min and 100℃ for 2 h, then cool to 8℃, add triethylamine and p-toluenesulfonyl chloride, and react for 20 h to obtain pretreated cellulose. Mix the pretreated cellulose, N,N-dimethylacetamide and ammonia evenly, and react for 20 h at 140℃ and 2.5 MPa to obtain aminated cellulose.

[0028] Step A3: Weigh the following raw materials in parts by weight: 80 parts PP masterbatch, 20 parts modified polylactic acid, 5 parts amino cellulose, 1 part 4-dimethylaminopyridine and 0.3 parts benzoyl peroxide. Add the raw materials to a twin-screw extruder and melt-extrude them under the following conditions: feeding section temperature 140℃, melting section temperature 180℃, homogenization section temperature 195℃, and die section temperature 140-150℃ to obtain bio-based biodegradable PP material.

[0029] The molar ratio of amino groups and modifiers on the modified polysiloxane described in step A1 is 1:1, the mass ratio of the modifier and lactide is 1:4, and the amount of stannous octoate is 2% of the mass of the modifier.

[0030] In step A2, the ratio of cellulose, N,N-dimethylacetamide, lithium chloride, triethylamine, and p-toluenesulfonyl chloride is 2g:50mL:5.5g:6mL:125mmol, the ratio of pretreated cellulose to ammonia is 1.5g:20mL, and the mass fraction of ammonia is 25%.

[0031] The PP masterbatch mentioned in step A3 is model HP501M.

[0032] The modified polysiloxane is prepared by the following steps:

[0033] Step B1: Tetramethylcyclotetrasiloxane, styrene, chloroplatinic acid and DMF are mixed evenly, and under nitrogen protection, the mixture is reacted for 6 hours at a speed of 200 r / min and a temperature of 70℃ to obtain a pretreated monomer. The pretreated monomer, silver nitrite, 2,2,6,6-tetramethylpiperidine oxide, sodium bromide and DMF are mixed evenly, and under nitrogen protection, the mixture is reacted for 2 hours at a speed of 60 r / min and a temperature of 35℃ to obtain a modified monomer.

[0034] Step B2: Lithium dimethylvinylsilane and tetrahydrofuran were mixed and protected with nitrogen. The mixture was stirred and modified monomers were added at a speed of 120 r / min and a temperature of 25 °C. After reacting for 6 h, tetrachlorosilane was added and the reaction was continued for 1 h to obtain pretreated polysiloxane. The pretreated polysiloxane, palladium on carbon catalyst and DMF were mixed evenly and hydrogen was introduced to a pressure of 0.3 MPa. The mixture was reacted at a speed of 60 r / min and a temperature of 80 °C for 4 h to obtain modified polysiloxane.

[0035] In step B1, the molar ratio of tetramethylcyclotetrasiloxane to styrene is 1:4, the amount of chloroplatinic acid is 1‰ of the mass of styrene, and the ratio of the amount of pretreatment monomer, silver nitrite, 2,2,6,6-tetramethylpiperidine oxide, sodium bromide and DMF is 100mmol:120mmol:10mmol:1mmol:200mL.

[0036] In step B2, the molar ratio of lithium dimethylvinylsilyl alcohol, modified monomer, and tetrachlorosilane is 2:8:1, and the amount of palladium catalyst on carbon is 5% of the mass of the pretreated polysiloxane.

[0037] The modifier is prepared by the following steps:

[0038] 3,4-Dihydroxybenzoic acid, glycidol, p-toluenesulfonic acid, and toluene were mixed evenly and reacted at 120 r / min and 115 °C for 2 h to obtain an intermediate. The intermediate, 4-formylphenylboronic acid, and DMF were mixed evenly and reacted under nitrogen protection at 200 r / min, 35 °C, and pH 8.5 for 4 h to obtain the modifier.

[0039] The molar ratio of 3,4-dihydroxybenzoic acid and glycidol is 1:1, the amount of p-toluenesulfonic acid is 2% of the mass of 3,4-dihydroxybenzoic acid and glycidol, and the molar ratio of the intermediate and 4-formylphenylboronic acid is 1:1.

[0040] Example 2, a method for preparing a bio-based biodegradable PP material, specifically includes the following steps:

[0041] Step A1: Mix the modified polysiloxane, modifier and DMF evenly, and react for 4 hours at a speed of 150 r / min, a temperature of 45℃ and a pH of 11 to obtain the modified additive. Mix the modified additive, lactide and DMF evenly, purge with nitrogen, stir and add stannous octoate at a speed of 120 r / min and a temperature of 125℃, raise the temperature to 145℃ and react for 9 hours at a pressure of 6000 Pa to obtain the modified polylactic acid.

[0042] Step A2: Mix cellulose and N,N-dimethylacetamide evenly, purge with nitrogen, stir and add lithium chloride at 120 r / min and 105℃ for 2.5 h, then cool to 9℃, add triethylamine and p-toluenesulfonyl chloride, and react for 23 h to obtain pretreated cellulose. Mix the pretreated cellulose, N,N-dimethylacetamide and ammonia evenly, and react for 20 h at 145℃ and 2.8 MPa to obtain aminated cellulose.

[0043] Step A3: Weigh the following raw materials in parts by weight: 90 parts PP masterbatch, 25 parts modified polylactic acid, 8 parts amino cellulose, 1.5 parts 4-dimethylaminopyridine and 0.4 parts benzoyl peroxide. Add the raw materials to a twin-screw extruder and melt-extrude them at the following temperatures: 145°C in the feeding section, 185°C in the melting section, 195°C in the homogenization section, and 145°C in the die section, to obtain bio-based biodegradable PP material.

[0044] The molar ratio of amino groups and modifiers on the modified polysiloxane described in step A1 is 1:1, the mass ratio of the modifier and lactide is 1:4, and the amount of stannous octoate is 2% of the mass of the modifier.

[0045] In step A2, the ratio of cellulose, N,N-dimethylacetamide, lithium chloride, triethylamine, and p-toluenesulfonyl chloride is 2g:50mL:5.5g:6mL:125mmol, the ratio of pretreated cellulose to ammonia is 1.5g:20mL, and the mass fraction of ammonia is 25%.

[0046] The PP masterbatch mentioned in step A3 is model HP501M.

[0047] The modified polysiloxane is prepared by the following steps:

[0048] Step B1: Tetramethylcyclotetrasiloxane, styrene, chloroplatinic acid and DMF are mixed evenly, and nitrogen gas is introduced for protection. The reaction is carried out for 7 hours at a speed of 200 r / min and a temperature of 75℃ to obtain a pretreated monomer. The pretreated monomer, silver nitrite, 2,2,6,6-tetramethylpiperidine oxide, sodium bromide and DMF are mixed evenly, and nitrogen gas is introduced for protection. The reaction is carried out for 3 hours at a speed of 60 r / min and a temperature of 40℃ to obtain a modified monomer.

[0049] Step B2: Lithium dimethylvinylsilane and tetrahydrofuran were mixed and protected with nitrogen. The mixture was stirred and modified monomers were added at a speed of 120 r / min and a temperature of 30 °C. After reacting for 7 h, tetrachlorosilane was added and the reaction was continued for 1.5 h to obtain pretreated polysiloxane. The pretreated polysiloxane, palladium on carbon catalyst and DMF were mixed evenly and hydrogen was introduced to a pressure of 0.4 MPa. The mixture was reacted at a speed of 60 r / min and a temperature of 85 °C for 4.5 h to obtain modified polysiloxane.

[0050] In step B1, the molar ratio of tetramethylcyclotetrasiloxane to styrene is 1:4, the amount of chloroplatinic acid is 1‰ of the mass of styrene, and the ratio of the amount of pretreatment monomer, silver nitrite, 2,2,6,6-tetramethylpiperidine oxide, sodium bromide and DMF is 100mmol:120mmol:10mmol:1mmol:200mL.

[0051] In step B2, the molar ratio of lithium dimethylvinylsilyl alcohol, modified monomer, and tetrachlorosilane is 2:8:1, and the amount of palladium catalyst on carbon is 5% of the mass of the pretreated polysiloxane.

[0052] The modifier is prepared by the following steps:

[0053] 3,4-Dihydroxybenzoic acid, glycidol, p-toluenesulfonic acid, and toluene were mixed evenly and reacted at 120 r / min and 120 °C for 2 h to obtain an intermediate. The intermediate, 4-formylphenylboronic acid, and DMF were mixed evenly and reacted under nitrogen protection at 300 r / min, 35 °C, and pH 9 for 5 h to obtain a modifier.

[0054] The molar ratio of 3,4-dihydroxybenzoic acid and glycidol is 1:1, the amount of p-toluenesulfonic acid is 2% of the mass of 3,4-dihydroxybenzoic acid and glycidol, and the molar ratio of the intermediate and 4-formylphenylboronic acid is 1:1.

[0055] Example 3, a method for preparing a bio-based biodegradable PP material, specifically includes the following steps:

[0056] Step A1: Mix the modified polysiloxane, modifier and DMF evenly, and react for 5 hours at a speed of 200 r / min, a temperature of 50℃ and a pH of 12 to obtain the modified additive. Mix the modified additive, lactide and DMF evenly, purge with nitrogen, stir and add stannous octoate at a speed of 150 r / min and a temperature of 130℃, raise the temperature to 150℃ and react for 10 hours at a pressure of 6000 Pa to obtain the modified polylactic acid.

[0057] Step A2: Mix cellulose and N,N-dimethylacetamide evenly, purge with nitrogen, stir and add lithium chloride at 150 r / min and 105℃ for 3 h, then cool to 10℃, add triethylamine and p-toluenesulfonyl chloride, and react for 25 h to obtain pretreated cellulose. Mix the pretreated cellulose, N,N-dimethylacetamide and ammonia evenly, and react for 25 h at 145℃ and 2.8 MPa to obtain aminated cellulose.

[0058] Step A3: Weigh the following raw materials in parts by weight: 100 parts PP masterbatch, 30 parts modified polylactic acid, 10 parts amino cellulose, 2 parts 4-dimethylaminopyridine and 0.5 parts benzoyl peroxide. Add the raw materials to a twin-screw extruder and melt-extrude them at the following temperatures: 150°C in the feeding section, 190°C in the melting section, 195°C in the homogenization section and 150°C in the die section, to obtain bio-based biodegradable PP material.

[0059] The molar ratio of amino groups and modifiers on the modified polysiloxane described in step A1 is 1:1, the mass ratio of the modifier and lactide is 1:4, and the amount of stannous octoate is 2% of the mass of the modifier.

[0060] In step A2, the ratio of cellulose, N,N-dimethylacetamide, lithium chloride, triethylamine, and p-toluenesulfonyl chloride is 2g:50mL:5.5g:6mL:125mmol, the ratio of pretreated cellulose to ammonia is 1.5g:20mL, and the mass fraction of ammonia is 25%.

[0061] The PP masterbatch mentioned in step A3 is model HP501M.

[0062] The modified polysiloxane is prepared by the following steps:

[0063] Step B1: Tetramethylcyclotetrasiloxane, styrene, chloroplatinic acid and DMF are mixed evenly, and nitrogen gas is introduced for protection. The reaction is carried out for 8 hours at a speed of 300 r / min and a temperature of 80℃ to obtain a pretreated monomer. The pretreated monomer, silver nitrite, 2,2,6,6-tetramethylpiperidine oxide, sodium bromide and DMF are mixed evenly, and nitrogen gas is introduced for protection. The reaction is carried out for 4 hours at a speed of 80 r / min and a temperature of 40℃ to obtain a modified monomer.

[0064] Step B2: Lithium dimethylvinylsilane and tetrahydrofuran were mixed and protected with nitrogen. The mixture was stirred and modified monomers were added at a speed of 150 r / min and a temperature of 30 °C. After reacting for 8 h, tetrachlorosilane was added and the reaction was continued for 1.5 h to obtain pretreated polysiloxane. The pretreated polysiloxane, palladium on carbon catalyst and DMF were mixed evenly and hydrogen was introduced to a pressure of 0.5 MPa. The mixture was reacted at a speed of 80 r / min and a temperature of 85 °C for 5 h to obtain modified polysiloxane.

[0065] In step B1, the molar ratio of tetramethylcyclotetrasiloxane to styrene is 1:4, the amount of chloroplatinic acid is 1‰ of the mass of styrene, and the ratio of the amount of pretreatment monomer, silver nitrite, 2,2,6,6-tetramethylpiperidine oxide, sodium bromide and DMF is 100mmol:120mmol:10mmol:1mmol:200mL.

[0066] In step B2, the molar ratio of lithium dimethylvinylsilyl alcohol, modified monomer, and tetrachlorosilane is 2:8:1, and the amount of palladium catalyst on carbon is 5% of the mass of the pretreated polysiloxane.

[0067] The modifier is prepared by the following steps:

[0068] 3,4-Dihydroxybenzoic acid, glycidol, p-toluenesulfonic acid, and toluene were mixed evenly and reacted at 150 r / min and 120 °C for 3 h to obtain an intermediate. The intermediate, 4-formylphenylboronic acid, and DMF were mixed evenly and reacted under nitrogen protection at 300 r / min, 40 °C, and pH 9 for 6 h to obtain a modifier.

[0069] The molar ratio of 3,4-dihydroxybenzoic acid and glycidol is 1:1, the amount of p-toluenesulfonic acid is 2% of the mass of 3,4-dihydroxybenzoic acid and glycidol, and the molar ratio of the intermediate and 4-formylphenylboronic acid is 1:1.

[0070] Comparative Example 1: This comparative example uses cellulose instead of aminated cellulose, but the other steps are the same as in Example 1.

[0071] Comparative Example 2: This comparative example did not include aminated cellulose compared to Example 1, but the remaining steps were the same.

[0072] Comparative Example 3: This comparative example uses pentaerythritol instead of the modifying additive compared to Example 1, with the remaining steps being the same.

[0073] Comparative Example 4: This comparative example uses glycidol instead of the modifier as in Example 1, but the other steps are the same.

[0074] The PP materials obtained in Examples 1-3 and Comparative Examples 1-4 were prepared into Type II specimens according to the standard of GB / T1040-2018, and the tensile strength was tested at a tensile rate of 20 mm / min. Notched Type A specimens were prepared according to GB / T1843-2008, and the impact strength was tested. The test results are shown in Table 1 below.

[0075] Table 1

[0076]

[0077] As shown in Table 1, this application is biodegradable and has excellent mechanical properties.

[0078] The above description is merely an example and illustration of the concept of the present invention. Those skilled in the art can make various modifications or additions to the specific embodiments described or use similar methods to replace them, as long as they do not deviate from the concept of the invention or exceed the scope defined in the claims, they should all fall within the protection scope of the present invention.

Claims

1. A method for preparing a bio-based biodegradable PP material, characterized in that: Specifically, the steps include the following: Step A1: Mix and react the modified polysiloxane, modifier and DMF to obtain the modified additive. Mix the modified additive, lactide and DMF evenly, purge with nitrogen for protection, stir and add stannous octoate, heat and react to obtain modified polylactic acid. Step A2: Mix cellulose and N,N-dimethylacetamide evenly, purge with nitrogen, stir and add lithium chloride, stir, cool and add triethylamine and p-toluenesulfonyl chloride to react and obtain pretreated cellulose. Mix the pretreated cellulose, N,N-dimethylacetamide and ammonia water to react and obtain aminated cellulose. Step A3: Weigh the following raw materials in parts by weight: 80-100 parts of PP masterbatch, 20-30 parts of modified polylactic acid, 5-10 parts of amino cellulose, 1-2 parts of 4-dimethylaminopyridine and 0.3-0.5 parts of benzoyl peroxide. Add the raw materials to a twin-screw extruder and melt extrude to obtain bio-based biodegradable PP material. The modified polysiloxane is prepared by the following steps: Step B1: Tetramethylcyclotetrasiloxane, styrene, chloroplatinic acid and DMF are mixed evenly, and the mixture is purged with nitrogen to carry out the reaction to obtain a pretreated monomer. The pretreated monomer, silver nitrite, 2,2,6,6-tetramethylpiperidine oxide, sodium bromide and DMF are mixed evenly, and the mixture is purged with nitrogen to carry out the reaction to obtain a modified monomer. Step B2: Lithium dimethylvinylsilane and tetrahydrofuran are mixed, nitrogen gas is introduced for protection, the mixture is stirred and modified monomers are added. After the reaction is carried out, tetrachlorosilane is added and the reaction is continued to obtain pretreated polysiloxane. The pretreated polysiloxane, palladium on carbon catalyst and DMF are mixed evenly and hydrogen gas is introduced to carry out the reaction to obtain modified polysiloxane. The modifier is prepared by the following steps: 3,4-Dihydroxybenzoic acid, glycidol, p-toluenesulfonic acid and toluene were mixed and reacted to obtain an intermediate. The intermediate, 4-formylphenylboronic acid and DMF were mixed evenly, and the mixture was subjected to nitrogen protection to carry out the reaction to obtain the modifier.

2. The method for preparing a bio-based biodegradable PP material according to claim 1, characterized in that: The molar ratio of amino groups on the modified polysiloxane to the modifier in step A1 is 1:1, and the mass ratio of the modifier to lactide is 1:

4.

3. The method for preparing a bio-based biodegradable PP material according to claim 1, characterized in that: The ratio of cellulose, N,N-dimethylacetamide, lithium chloride, triethylamine and p-toluenesulfonyl chloride in step A2 is 2g:50mL:5.5g:6mL:125mmol, and the ratio of pretreated cellulose to ammonia is 1.5g:20mL.

4. The method for preparing a bio-based biodegradable PP material according to claim 1, characterized in that: The molar ratio of tetramethylcyclotetrasiloxane and styrene in step B1 is 1:4, and the ratio of pretreatment monomer, silver nitrite, 2,2,6,6-tetramethylpiperidine oxide, sodium bromide and DMF is 100mmol:120mmol:10mmol:1mmol:200mL.

5. The method for preparing a bio-based biodegradable PP material according to claim 1, characterized in that: The molar ratio of lithium dimethylvinylsilane, modified monomer and tetrachlorosilane in step B2 is 2:8:

1.

6. The method for preparing a bio-based biodegradable PP material according to claim 1, characterized in that: The molar ratio of 3,4-dihydroxybenzoic acid and glycidol is 1:1, and the molar ratio of the intermediate and 4-formylphenylboronic acid is 1:

1.

7. A bio-based biodegradable PP material, characterized in that: It is prepared according to any one of the preparation methods described in claims 1-6.

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