A high-toughness impact-resistant PP material and its preparation method

Abstract

The present invention provides a method for preparing a high-toughness and impact-resistant PP material. The preparation method comprises the following steps: S1. Prepare a PLA solution; S2. Divide the PLA solution prepared in step S1 into two portions, and add sodium alginate powder to one of the portions; S3. Add porous carbon / silica composite microspheres to the remaining PLA in step S2; S4. Mix the solutions in steps S2 and S3 to obtain a PLA composite solution, and perform electrospinning to obtain an electrospun membrane loaded with porous carbon / silica composite microspheres; S5. Immerse the electrospun membrane prepared in step S4 in warm water with ultrasonic oscillation, and then dry and pulverize it to obtain a flaky electrospun membrane loaded with porous carbon / silica composite microspheres; S6. Blend the flaky electrospun membrane loaded with porous carbon / silica composite microspheres with PP particles and then extrude and pelletize them to obtain the high-toughness and impact-resistant PP material. By adding the flaky electrospun membrane loaded with porous carbon / silica composite microspheres, the present invention improves the impact resistance of the PP material.

Description

Technical Field

[0001] The present invention relates to the field of polymer materials, and particularly relates to a high-toughness impact-resistant PP material and a preparation method thereof. Background Art

[0002] Polypropylene (PP) is a linear chain hydrocarbon polymer that has certain similarities in properties with polyethylene. However, due to the structure in which side methyl groups are alternately connected to the main chain of polypropylene, polypropylene is different from polyethylene in properties and has great variations. Since the main chain carbon atoms to which the side methyl groups in polypropylene are attached are tertiary carbon atoms, this makes them active and easily attacked by oxygen to undergo oxidation. The carbon chain is also prone to chain breakage under the action of heat, ultraviolet light or other high-energy rays, and no crosslinking occurs. Due to the symmetry of the tertiary carbon atoms, there is a phenomenon of spatial isomerism in polypropylene, forming three spatial isomers: isotactic polypropylene (the side methyl groups on its main chain are all distributed on one side of the molecular chain), syndiotactic polypropylene (the side methyl groups on its main chain are alternately distributed on both sides of the molecular chain), and atactic polypropylene (the side methyl groups on its main chain are distributed on both sides of the molecular chain in an irregular form).

[0003] Polypropylene has many self-advantages. Its raw materials are rich in sources, low in price, have good mechanical properties, are not easy to absorb water, have heat resistance, wear resistance, chemical stability, etc., and its comprehensive performance is good. However, it also has other defects. For example, polypropylene is prone to embrittlement at low temperatures, has a large shrinkage rate after molding, is not resistant to aging, and is sensitive to notches, which will all limit the application range of polypropylene to a certain extent. To solve the above disadvantages, people have improved and enhanced its performance by modifying it. The most commonly used methods for polypropylene are copolymerization, blending, reinforcement, filling, etc. Among them, filling and reinforcement modification is currently the most promising and widely used. The modified polypropylene can be widely used in fields such as aerospace, aviation, furniture industry, automobiles, textile industry, and electrical manufacturing. Summary of the Invention

[0004] Technical problem to be solved: The purpose of the present invention is to provide a high-toughness impact-resistant PP material and a preparation method thereof, and by adding a sheet-like electrospun membrane loaded with porous carbon / silica composite microspheres, the impact resistance of the PP material is improved.

[0005] Technical solution: A high-toughness impact-resistant PP material, the high-toughness impact-resistant PP material is composed of PP and a sheet-like electrospun membrane loaded with porous carbon / silica composite microspheres, and the area of the sheet-like electrospun membrane is 0.02 - 0.1 cm 2 .

[0006] The preparation method of the above-mentioned high-toughness impact-resistant PP material, the preparation method includes the following steps:

[0007] S1. After drying the PLA particles, dissolve them in dichloromethane to prepare a PLA solution.

[0008] S2. Divide the PLA solution prepared in step S1 into two parts. Add sodium alginate powder to one part and mix and stir evenly; S3. Add porous carbon / silica composite microspheres to the remaining PLA in step S2 and mix and stir evenly.

[0009] S4. Mix the solutions in steps S2 and S3 to obtain a PLA composite solution. Electrospin the PLA composite solution to obtain an electrospun membrane loaded with porous carbon / silica composite microspheres.

[0010] S5. Immerse the electrospun membrane prepared in step S4 in warm water and ultrasonically oscillate it, then take it out and dry it. Crush the electrospun membrane to obtain a flaky electrospun membrane loaded with porous carbon / silica composite microspheres.

[0011] S6. Blend the flaky electrospun membrane loaded with porous carbon / silica composite microspheres with PP particles and then extrude and pelletize to obtain a high-toughness impact-resistant PP material.

[0012] Preferably, the concentration of the PLA solution in step S1 is 5-8 wt%.

[0013] Preferably, the preparation method of the porous carbon / silica composite microspheres in step S3 includes the following steps:

[0014] S11. Add tetraethyl orthosilicate to anhydrous ethanol and mix and stir evenly, then add a certain amount of polyethylene glycol 400 to obtain a tetraethyl orthosilicate solution. Drop the tetraethyl orthosilicate solution into a 1-2 mol / L hydrochloric acid solution. After dropping, continue to stir for 100-160 min to obtain a sol. Then add pollen particles and impregnate them under vacuum for 20-40 min to make the sol fully adsorb on the surface of the pollen. Centrifuge and dry, and sinter to obtain hollow mesoporous silica.

[0015] S12. Add cellulose fibers to the NaOH / urea / water solvent system, mix and stir at low temperature to dissolve, then add CaCl2 and stir and react at room temperature to obtain a cellulose sol.

[0016] S13. Add hollow mesoporous silica to the cellulose sol and stir evenly to coat a layer of cellulose sol on the surface of the hollow mesoporous silica. Filter to obtain cellulose / silica composite microspheres, and freeze-dry the composite microspheres to obtain porous cellulose / silica composite microspheres.

[0017] S14. Calcinate the porous cellulose / silica composite microspheres prepared in step S13 under the protection of argon to obtain porous carbon / silica composite microspheres.

[0018] Preferably, in the step S4, the content of sodium alginate in the PLA composite solution is 0.5-1 wt%, and the content of the porous carbon / silica composite microspheres is 3-5 wt%.

[0019] Preferably, in the step S5, the temperature of the warm water is 30-40 °C, and the time of ultrasonic oscillation is 10-30 min.

[0020] Preferably, in the step S6, the mass ratio of the sheet-shaped electrospun membrane loaded with the porous carbon / silica composite microspheres to the PP particles is 3.5-5.5:100.

[0021] Preferably, in the step S11, the volume ratio of tetraethyl orthosilicate, absolute ethanol, polyethylene glycol 400 and hydrochloric acid solution is 12-16:25-40:2-3:100-120, the sintering temperature is 550-650 °C, and the sintering time is 5-10 h.

[0022] Preferably, in the step S12, the content of CaCl2 in the cellulose sol is 0.5-1.2 wt%.

[0023] Preferably, in the step S14, the calcination temperature is 800-900 °C, and the time is 2-3 h.

[0024] Beneficial effects: The PP material of the present invention has the following advantages:

[0025] 1. In the present invention, the porous carbon / silica composite microspheres are prepared by combining the structure of the biomimetic material. The prepared porous carbon / silica composite microspheres are hollow microspheres with a gradually changing pore size structure. The outer side of the microspheres is made of porous carbon, and the inner side is made of porous silica. The pore size of the porous carbon is smaller than that of the silica. This gradually changing pore size structure can effectively absorb external energy and improve the impact resistance of PP.

[0026] 2. In the present invention, carbon and silica are used to prepare composite microspheres. The hardness of titanium dioxide is high and is set as the inner layer of the microspheres, and the hardness of carbon is low and is set as the inner layer. Through the cooperation of hard and soft, the energy absorption effect of the material is improved, thereby improving the impact resistance effect.

[0027] 3. In the present invention, CaCl2 is added to the carbon layer, and sodium alginate is added to the PLA. CaCl2 and sodium alginate can react. Therefore, the composite microspheres can be firmly fixed on the electrospun membrane of the PLA. After preparing the electrospun membrane loaded with the porous carbon / silica composite microspheres, the electrospun membrane is crushed to 0.02-0.1 cm 2 , and the membrane with this area size is blended with PP at high temperature. Due to the high temperature, PLA can be partially melt-blended with PP to improve the compatibility. Specific embodiments

[0028] The present invention will be further described below in conjunction with embodiments. The following embodiments are explanations of the present invention, and the present invention is not limited to the following embodiments:

[0029] Example 1

[0030] A method for preparing porous carbon / silica composite microspheres, comprising the following steps:

[0031] S11. Add tetraethyl orthosilicate to absolute ethanol, mix and stir evenly, then add a certain amount of polyethylene glycol 400 to obtain a tetraethyl orthosilicate solution. Drop the tetraethyl orthosilicate solution into a 1 mol / L hydrochloric acid solution. The volume ratio of tetraethyl orthosilicate, absolute ethanol, polyethylene glycol 400 and hydrochloric acid solution is 12:25:2:100. After dropping, continue to stir for 100 min to obtain a sol. Then add pollen particles and impregnate under vacuum for 20 min to allow the sol to be fully adsorbed on the surface of the pollen. Centrifuge and dry, and sinter at a sintering temperature of 550 °C for 10 h to obtain hollow mesoporous silica;

[0032] S12. Add cellulose fibers to the NaOH / urea / water solvent system, mix and stir at low temperature to dissolve, then add CaCl2 and stir and react at room temperature to obtain a cellulose sol. The content of CaCl2 in the cellulose sol is 1.2 wt%;

[0033] S13. Add hollow mesoporous silica to the cellulose sol, stir evenly, coat a layer of cellulose sol on the surface of the hollow mesoporous silica, filter to obtain cellulose / silica composite microspheres, and freeze-dry the composite microspheres at a freeze-drying temperature of -50 °C for 20 h to obtain porous cellulose / silica composite microspheres;

[0034] S14. Calcinate the porous cellulose / silica composite microspheres prepared in step S13 under the protection of argon at a calcination temperature of 800 °C for 3 h to obtain porous carbon / silica composite microspheres.

[0035] Example 2

[0036] A method for preparing porous carbon / silica composite microspheres, comprising the following steps:

[0037] S11. Add tetraethyl orthosilicate to absolute ethanol, mix and stir evenly, then add a certain amount of polyethylene glycol 400 to obtain a tetraethyl orthosilicate solution. Drop the tetraethyl orthosilicate solution into a 2 mol / L hydrochloric acid solution. The volume ratio of tetraethyl orthosilicate, absolute ethanol, polyethylene glycol 400 and hydrochloric acid solution is 16:40:3:120. After dropping, continue to stir for 160 min to obtain a sol. Then add pollen grains and impregnate under vacuum for 40 min to allow the sol to fully adsorb on the surface of the pollen. Centrifuge and dry, and sinter at a sintering temperature of 650 °C for 5 h to obtain hollow mesoporous silica;

[0038] S12. Add cellulose fibers to the NaOH / urea / water solvent system, mix and stir at low temperature to dissolve, then add CaCl2 and stir and react at room temperature to obtain a cellulose sol. The content of CaCl2 in the cellulose sol is 0.5 wt%;

[0039] S13. Add hollow mesoporous silica to the cellulose sol, stir evenly, coat a layer of cellulose sol on the surface of the hollow mesoporous silica, filter to obtain cellulose / silica composite microspheres, and freeze-dry the composite microspheres at a freeze-drying temperature of -60 °C for 20 h to obtain porous cellulose / silica composite microspheres;

[0040] S14. Calcinate the porous cellulose / silica composite microspheres prepared in step S13 under the protection of argon at a calcination temperature of 900 °C for 2 h to obtain porous carbon / silica composite microspheres.

[0041] Example 3

[0042] A method for preparing porous carbon / silica composite microspheres, comprising the following steps:

[0043] S11. Add tetraethyl orthosilicate to absolute ethanol, mix and stir evenly, then add a certain amount of polyethylene glycol 400 to obtain a tetraethyl orthosilicate solution. Drop the tetraethyl orthosilicate solution into a 1 mol / L hydrochloric acid solution. The volume ratio of tetraethyl orthosilicate, absolute ethanol, polyethylene glycol 400 and hydrochloric acid solution is 13:30:2:105. After dropping, continue to stir for 140 min to obtain a sol. Then add pollen grains and impregnate under vacuum for 25 min to allow the sol to fully adsorb on the surface of the pollen. Centrifuge and dry, and sinter at a sintering temperature of 580 °C for 7 h to obtain hollow mesoporous silica;

[0044] S12. Add cellulose fibers to the NaOH / urea / water solvent system, mix and stir at low temperature to dissolve, then add CaCl2 and stir and react at room temperature to obtain a cellulose sol. The content of CaCl2 in the cellulose sol is 0.8 wt%;

[0045] S13. Add hollow mesoporous silica into the cellulose sol, stir evenly, coat a layer of cellulose sol on the surface of the hollow mesoporous silica, filter to obtain cellulose / silica composite microspheres, and subject the composite microspheres to freeze-drying at a freeze-drying temperature of -60 °C for 20 h to obtain porous cellulose / silica composite microspheres;

[0046] S14. Calcinate the porous cellulose / silica composite microspheres prepared in step S13 under the protection of argon at a calcination temperature of 800 °C for 2.5 h to obtain porous carbon / silica composite microspheres.

[0047] Example 4

[0048] A preparation method of porous carbon / silica composite microspheres, comprising the following steps:

[0049] S11. Add tetraethyl orthosilicate into absolute ethanol and mix and stir evenly, then add a certain amount of polyethylene glycol 400 to obtain a tetraethyl orthosilicate solution. Drop the tetraethyl orthosilicate solution into a 1 mol / L hydrochloric acid solution. The volume ratio of tetraethyl orthosilicate, absolute ethanol, polyethylene glycol 400 and hydrochloric acid solution is 16:36:3:115. After dropping, continue to stir for 120 min to obtain a sol, then add pollen particles, impregnate under vacuum for 35 min to make the sol fully adsorb on the pollen surface, centrifuge and dry, and sinter at a sintering temperature of 620 °C for 9 h to obtain hollow mesoporous silica;

[0050] S12. Add cellulose fibers into the NaOH / urea / water solvent system, mix and stir at low temperature to dissolve, then add CaCl2, and stir and react at room temperature to obtain a cellulose sol. The content of CaCl2 in the cellulose sol is 1 wt%;

[0051] S13. Add hollow mesoporous silica into the cellulose sol, stir evenly, coat a layer of cellulose sol on the surface of the hollow mesoporous silica, filter to obtain cellulose / silica composite microspheres, and subject the composite microspheres to freeze-drying at a freeze-drying temperature of -65 °C for 12 h to obtain porous cellulose / silica composite microspheres;

[0052] S14. Calcinate the porous cellulose / silica composite microspheres prepared in step S13 under the protection of argon at a calcination temperature of 850 °C for 3 h to obtain porous carbon / silica composite microspheres.

[0053] Table 1

[0054] Average pore diameter of silica layer / nm Average pore diameter of carbon layer / nm Example 1 12.9 5.6 Example 2 11.8 5.8 Example 3 13.2 5.5 Example 4 13.8 5.9

[0055] Example 5

[0056] Preparation method of high-toughness and impact-resistant PP material, the preparation method comprising the following steps:

[0057] S1. After drying the PLA particles, dissolve them in dichloromethane to prepare a 5wt% PLA solution;

[0058] S2. Divide the PLA solution prepared in step S1 into two parts, and add sodium alginate powder to one of the parts, and mix and stir evenly;

[0059] S3. Add the porous carbon / silica composite microspheres prepared in Example 1 to the remaining PLA in step S2, and mix and stir evenly;

[0060] S4. Mix the solutions in steps S2 and S3 to obtain a PLA composite solution. The content of sodium alginate in the PLA composite solution is 1wt%, and the content of the porous carbon / silica composite microspheres is 5wt%. Electrospinning the PLA composite solution to obtain an electrospun membrane loaded with porous carbon / silica composite microspheres;

[0061] S5. Immerse the electrospun membrane prepared in step S4 in warm water and perform ultrasonic oscillation, then take it out and dry it. The temperature of the warm water is 30°C, and the time of ultrasonic oscillation is 30 min. Crush the electrospun membrane to obtain a flaky electrospun membrane with an average area of 0.05 cm 2 , to obtain a flaky electrospun membrane loaded with porous carbon / silica composite microspheres;

[0062] S6. Blend the flaky electrospun membrane loaded with porous carbon / silica composite microspheres with PP particles and then extrude and pelletize to obtain a high-toughness and impact-resistant PP material. The mass ratio of the flaky electrospun membrane loaded with porous carbon / silica composite microspheres to PP particles is 3.5:100.

[0063] Example 6

[0064] Preparation method of high-toughness and impact-resistant PP material, the preparation method comprising the following steps:

[0065] S1. After drying the PLA particles, dissolve them in dichloromethane to prepare an 8wt% PLA solution;

[0066] S2. Divide the PLA solution prepared in step S1 into two parts, and add sodium alginate powder to one of the parts, and mix and stir evenly;

[0067] S3. Add the porous carbon / silica composite microspheres prepared in Example 2 to the remaining PLA in step S2, and mix and stir evenly;

[0068] S4. Mix the solutions in steps S2 and S3 to obtain a PLA composite solution. The content of sodium alginate in the PLA composite solution is 0.5 wt%, and the content of the porous carbon / silica composite microspheres is 3 wt%. Electrospun the PLA composite solution to obtain an electrospun membrane loaded with porous carbon / silica composite microspheres;

[0069] S5. Immerse the electrospun membrane prepared in step S4 in warm water with ultrasonic vibration, then take it out and dry it. The temperature of the warm water is 40 °C, and the time of ultrasonic vibration is 10 min. Crush the electrospun membrane to obtain a flaky electrospun membrane with an average area of 0.03 cm 2 , and obtain a flaky electrospun membrane loaded with porous carbon / silica composite microspheres;

[0070] S6. Blend the flaky electrospun membrane loaded with porous carbon / silica composite microspheres with PP particles and then extrude and pelletize to obtain a high-toughness impact-resistant PP material. The mass ratio of the flaky electrospun membrane loaded with porous carbon / silica composite microspheres to PP particles is 5.5:100.

[0071] Example 7

[0072] A preparation method of a high-toughness impact-resistant PP material, the preparation method comprising the following steps:

[0073] S1. Dry the PLA particles and then dissolve them in dichloromethane to prepare a 6.2 wt% PLA solution;

[0074] S2. Divide the PLA solution prepared in step S1 into two parts, and add sodium alginate powder to one of the parts and mix and stir evenly;

[0075] S3. Add the porous carbon / silica composite microspheres prepared in Example 3 to the remaining PLA in step S2 and mix and stir evenly;

[0076] S4. Mix the solutions in steps S2 and S3 to obtain a PLA composite solution. The content of sodium alginate in the PLA composite solution is 0.75 wt%, and the content of the porous carbon / silica composite microspheres is 3.5 wt%. Electrospun the PLA composite solution to obtain an electrospun membrane loaded with porous carbon / silica composite microspheres;

[0077] S5. Immerse the electrospun membrane prepared in step S4 in warm water with ultrasonic vibration, then take it out and dry it. The temperature of the warm water is 40 °C, and the time of ultrasonic vibration is 20 min. Crush the electrospun membrane to obtain a flaky electrospun membrane with an average area of 0.06 cm 2 , and obtain a flaky electrospun membrane loaded with porous carbon / silica composite microspheres;

[0078] S6. Blend the sheet-like electrospun membrane of the loaded porous carbon / silica composite microspheres with PP particles and then extrude and granulate to obtain a high-toughness and impact-resistant PP material. The mass ratio of the sheet-like electrospun membrane of the loaded porous carbon / silica composite microspheres to PP particles is 5:100.

[0079] Example 8

[0080] Preparation method of a high-toughness and impact-resistant PP material, the preparation method comprising the following steps:

[0081] S1. After drying the PLA particles, dissolve them in dichloromethane to prepare a 7.5 wt% PLA solution.

[0082] S2. Divide the PLA solution prepared in step S1 into two parts, and add sodium alginate powder to one of them, and mix and stir evenly.

[0083] S3. Add the porous carbon / silica composite microspheres prepared in Example 4 to the remaining PLA in step S2, and mix and stir evenly.

[0084] S4. Mix the solutions in steps S2 and S3 to obtain a PLA composite solution. The content of sodium alginate in the PLA composite solution is 0.55 wt%, and the content of the porous carbon / silica composite microspheres is 4.5 wt%. Electrospin the PLA composite solution to obtain an electrospun membrane loaded with porous carbon / silica composite microspheres.

[0085] S5. Immerse the electrospun membrane prepared in step S4 in warm water and ultrasonically vibrate, then take it out and dry. The temperature of the warm water is 30 °C, and the time of ultrasonic vibration is 25 min. Crush the electrospun membrane to obtain a sheet-like electrospun membrane with an average area of 0.06 cm 2 , to obtain a sheet-like electrospun membrane loaded with porous carbon / silica composite microspheres.

[0086] S6. Blend the sheet-like electrospun membrane of the loaded porous carbon / silica composite microspheres with PP particles and then extrude and granulate to obtain a high-toughness and impact-resistant PP material. The mass ratio of the sheet-like electrospun membrane of the loaded porous carbon / silica composite microspheres to PP particles is 4:100.

[0087] Example 9

[0088] Preparation method of a high-toughness and impact-resistant PP material, the preparation method comprising the following steps:

[0089] S1. After drying the PLA particles, dissolve them in dichloromethane to prepare a 7 wt% PLA solution.

[0090] S2. Divide the PLA solution prepared in step S1 into two portions. Add sodium alginate powder to one of the portions and mix well by stirring.

[0091] S3. Add the porous carbon / silica composite microspheres prepared in Example 4 to the remaining PLA in step S2 and mix well by stirring.

[0092] S4. Mix the solutions in steps S2 and S3 to obtain a PLA composite solution. The content of sodium alginate in the PLA composite solution is 0.65 wt%, and the content of the porous carbon / silica composite microspheres is 4 wt%. Electrospin the PLA composite solution to obtain an electrospun membrane loaded with the porous carbon / silica composite microspheres.

[0093] S5. Immerse the electrospun membrane prepared in step S4 in warm water and perform ultrasonic oscillation, then take it out and dry it. The temperature of the warm water is 35 °C, and the time of ultrasonic oscillation is 25 min. Crush the electrospun membrane to obtain a flaky electrospun membrane with an average area of 0.07 cm 2 , and obtain a flaky electrospun membrane loaded with the porous carbon / silica composite microspheres.

[0094] S6. Blend the flaky electrospun membrane loaded with the porous carbon / silica composite microspheres with PP particles and then extrude and pelletize to obtain a high-toughness impact-resistant PP material. The mass ratio of the flaky electrospun membrane loaded with the porous carbon / silica composite microspheres to the PP particles is 4.5:100.

[0095] Comparative Example 1

[0096] A method for preparing a high-toughness impact-resistant PP material, the preparation method comprising the following steps:

[0097] S1. Blend the porous carbon / silica composite microspheres prepared in Example 4 with PP particles and then extrude and pelletize to obtain a high-toughness impact-resistant PP material. The mass ratio of the loaded porous carbon / silica composite microspheres to the PP particles is 12:100.

[0098] Comparative Example 2

[0099] A method for preparing a high-toughness impact-resistant PP material, the preparation method comprising the following steps:

[0100] S1. Dry the PLA particles and then dissolve them in dichloromethane to prepare a 7 wt% PLA solution.

[0101] S2. Add the porous carbon / silica composite microspheres prepared in Example 4 to the PLA solution prepared in step S1 and mix well by stirring.

[0102] S3. Electrospin the solution in step S2 with the content of porous carbon / silica composite microspheres being 4 wt% to obtain an electrospun membrane loaded with porous carbon / silica composite microspheres;

[0103] S4. Crush the electrospun membrane prepared in step S4 to obtain a flaky electrospun membrane with an average area of 0.06 cm 2 , and obtain a flaky electrospun membrane loaded with porous carbon / silica composite microspheres;

[0104] S5. Blend the flaky electrospun membrane loaded with porous carbon / silica composite microspheres with PP particles and then extrude and pelletize to obtain a high-toughness impact-resistant PP material. The mass ratio of the flaky electrospun membrane loaded with porous carbon / silica composite microspheres to PP particles is 4.5:100.

[0105] Comparative Example 3

[0106] A preparation method of a high-toughness impact-resistant PP material, the preparation method comprising the following steps:

[0107] S1. After drying the PLA particles, dissolve them in dichloromethane to prepare a 7.5 wt% PLA solution;

[0108] S2. Divide the PLA solution prepared in step S1 into two parts. Add sodium alginate powder to one part and mix and stir evenly; S3. Add silica composite microspheres to the remaining PLA in step S2 and mix and stir evenly;

[0109] S4. Mix the solutions in steps S2 and S3 to obtain a PLA composite solution. The content of sodium alginate in the PLA composite solution is 0.55 wt%, and the content of silica composite microspheres is 4.5 wt%. Electrospin the PLA composite solution to obtain an electrospun membrane loaded with silica composite microspheres;

[0110] S5. Immerse the electrospun membrane prepared in step S4 in warm water with ultrasonic oscillation, then take it out and dry it. The temperature of the warm water is 30 °C, and the time of ultrasonic oscillation is 25 min. Crush the electrospun membrane to obtain a flaky electrospun membrane with an average area of 0.06 cm 2 , and obtain a flaky electrospun membrane loaded with silica composite microspheres;

[0111] S6. Blend the flaky electrospun membrane loaded with silica composite microspheres with PP particles and then extrude and pelletize to obtain a high-toughness impact-resistant PP material. The mass ratio of the flaky electrospun membrane loaded with silica composite microspheres to PP particles is 4:100;

[0112] Among them, the preparation method of the silica composite microspheres includes the following steps:

[0113] S11. Add tetraethyl orthosilicate to absolute ethanol, mix and stir evenly, then add a certain amount of polyethylene glycol 400 to obtain a tetraethyl orthosilicate solution. Drop the tetraethyl orthosilicate solution into 1 mol / L hydrochloric acid solution. The volume ratio of tetraethyl orthosilicate, absolute ethanol, polyethylene glycol 400 and hydrochloric acid solution is 16:36:3:115. After dropping, continue to stir for 120 min to obtain a sol. Then add pollen particles and impregnate them under vacuum for 35 min to allow the sol to fully adsorb on the surface of the pollen. Centrifuge and dry, and sinter at a sintering temperature of 620 °C for 9 h to obtain hollow mesoporous silica;

[0114] S12. Prepare the sol according to the above ratio. The difference is that the sol does not contain polyethylene glycol 400 and CaCl2 is added, and its content in the sol is 1%. Immerse the hollow mesoporous silica prepared in step S11 in the sol prepared in this step again under vacuum for 30 min, centrifuge and dry, and sinter at a sintering temperature of 600 °C for 10 h to obtain silica composite microspheres.

[0115] Comparative Example 4

[0116] Preparation method of high-toughness impact-resistant PP material, the preparation method includes the following steps:

[0117] S1. After drying the PLA particles, dissolve them in dichloromethane to prepare a 7 wt% PLA solution;

[0118] S2. Divide the PLA solution prepared in step S1 into two parts, and add sodium alginate powder to one part and mix and stir evenly; S3. Add porous carbon / silica composite microspheres to the remaining PLA in step S2 and mix and stir evenly;

[0119] S4. Mix the solutions in steps S2 and S3 to obtain a PLA composite solution. The content of sodium alginate in the PLA composite solution is 0.65 wt%, and the content of porous carbon / silica composite microspheres is 4 wt%. Electrospun the PLA composite solution to obtain an electrospun membrane loaded with porous carbon / silica composite microspheres;

[0120] S5. Immerse the electrospun membrane prepared in step S4 in warm water for ultrasonic oscillation, then take it out and dry. The temperature of the warm water is 35 °C, and the time of ultrasonic oscillation is 25 min. Crush the electrospun membrane to obtain a flaky electrospun membrane with an average area of 0.07 cm 2 , to obtain a flaky electrospun membrane loaded with porous carbon / silica composite microspheres;

[0121] S6. The sheet-like electrospun membrane of the loaded porous carbon / silica composite microspheres is blended with PP particles and then extruded and granulated to obtain a high-toughness and impact-resistant PP material. The mass ratio of the sheet-like electrospun membrane of the loaded porous carbon / silica composite microspheres to the PP particles is 4.5:100;

[0122] Among them, the preparation method of the porous carbon / silica composite microspheres includes the following steps:

[0123] S11. Tetraethyl orthosilicate is added to absolute ethanol and mixed and stirred evenly, and then a certain amount of polyethylene glycol 400 is added to obtain a tetraethyl orthosilicate solution. The tetraethyl orthosilicate solution is dropped into a 1.5 mol / L hydrochloric acid solution. The volume ratio of tetraethyl orthosilicate, absolute ethanol, polyethylene glycol 400, and hydrochloric acid solution is 16:36:2.5:110. After the dropping is completed, stirring is continued for 120 min to obtain a sol. Then pollen particles are added and impregnated under vacuum for 35 min to allow the sol to be fully adsorbed on the surface of the pollen. After centrifugation and drying, sintering is carried out. The sintering temperature is 620 °C and the sintering time is 9 h to obtain hollow mesoporous silica;

[0124] S12. Cellulose fibers are added to the NaOH / urea / water solvent system and dissolved by mixing and stirring at low temperature. Then polyethylene glycol and CaCl2 are added and stirred and reacted at room temperature to obtain a cellulose sol. The content of polyethylene glycol in the cellulose sol is 1.5%, and the content of CaCl2 in the cellulose sol is 1 wt%;

[0125] S13. Hollow mesoporous silica is added to the cellulose sol and stirred evenly to coat a layer of cellulose sol on the surface of the hollow mesoporous silica. After filtration, cellulose / silica composite microspheres are obtained. The composite microspheres are freeze-dried. The freeze-drying temperature is -65 °C and the time is 12 h to obtain porous cellulose / silica composite microspheres;

[0126] S14. The porous cellulose / silica composite microspheres prepared in step S13 are calcined under the protection of argon. The calcination temperature is 850 °C and the time is 3 h to obtain porous carbon / silica composite microspheres. The pore diameter of the silica layer in the obtained microspheres is 13.5 nm, and the pore diameter of the carbon layer is 15.6 nm.

[0127] Performance test: The PP particles prepared in the examples and comparative examples are made into the shapes specified in the following test methods, and performance tests are carried out according to the following test methods:

[0128] Tensile property test: Tensile test is carried out on a universal testing machine according to GB / T1040-92. The test temperature is 23 ± 2 °C, the size of the test part is 150 mm × 10 mm × 4 mm, and the test speed is 10 mm / min;

[0129] Impact performance test:

[0130] The notched impact experiment was carried out on a cantilever beam impact testing machine in accordance with GB / T1843-1996. The test temperature was 23±2°C. The dimensions of the test part were 100mm×80mm×4mm. The A-type notch was adopted, with the bottom radius of the notch being 0.20±0.05mm and the angle being 45°±1°;

[0131] The tensile test was carried out on a universal testing machine in accordance with GB / T9341-88. The test temperature was 23±2°C. The dimensions of the test part were 80mm×10mm×4mm. The test speed was 2mm / min.

[0132] Table 2

[0133] Tensile strength (MPa) <![CDATA[Impact strength (KJ / m 2 )]]> Flexural strength / MPa Example 5 39.65 8.41 61.64 Example 6 42.31 8.37 63.78 Example 7 43.58 8.29 62.45 Example 8 40.69 8.48 61.28 Example 9 43.56 8.56 62.13 Comparative Example 1 32.16 7.58 56.23 Comparative Example 2 35.14 7.29 50.36 Comparative Example 3 34.56 7.54 52.69 Comparative Example 4 33.65 7.32 53.98 Pure PP 27.91 7.24 45.69

[0134] Obviously, the above-mentioned embodiments are only examples for clear illustration and not limitations on the implementation manners. For those of ordinary skill in the art, other different forms of changes or modifications can be made based on the above description. It is not necessary and impossible to list all the implementation manners here. And the obvious changes or modifications derived therefrom are still within the protection scope of the present invention.

Claims

1. A high-toughness and impact-resistant PP material, characterized in that: The high-toughness impact-resistant PP material is composed of PP and a sheet-like electrospun membrane loaded with porous carbon / silica composite microspheres, and the area of the sheet-like electrospun membrane is 0.02 - 0.1 cm 2 ; The preparation method of the above-mentioned high-toughness impact-resistant PP material, the preparation method includes the following steps: S1. After drying the PLA particles, dissolve them in dichloromethane to prepare a PLA solution with a concentration of 5-8 wt%. S2. Divide the PLA solution prepared in step S1 into two parts, and add sodium alginate powder to one of them, and mix and stir evenly. S3. Add porous carbon / silica composite microspheres to the remaining PLA in step S2, and mix and stir evenly. S4. Mix the solutions in steps S2 and S3 to obtain a PLA composite solution. The content of sodium alginate in the PLA composite solution is 0.5-1 wt%, and the content of porous carbon / silica composite microspheres is 3-5 wt%. Electrospinning the PLA composite solution to obtain an electrospun membrane loaded with porous carbon / silica composite microspheres. S5. Immerse the electrospun membrane prepared in step S4 in warm water and ultrasonically oscillate it, then take it out and dry it. Crush the electrospun membrane to obtain a flaky electrospun membrane loaded with porous carbon / silica composite microspheres. S6. Blend the flaky electrospun membrane loaded with porous carbon / silica composite microspheres with a mass ratio of 3.5-5.5:100 and PP particles, and then extrude and pelletize to obtain a high-toughness impact-resistant PP material. Among them, the preparation method of the porous carbon / silica composite microspheres in step S3 includes the following steps: S11. Add tetraethyl orthosilicate to anhydrous ethanol and mix and stir evenly, then add a certain amount of polyethylene glycol 400 to obtain a tetraethyl orthosilicate solution. Drop the tetraethyl orthosilicate solution into a 1-2 mol / L hydrochloric acid solution. After dropping, continue to stir for 100-160 min to obtain a sol. Then add pollen particles and impregnate them under vacuum for 20-40 min to make the sol fully adsorb on the surface of the pollen. Centrifuge and dry, and sinter to obtain hollow mesoporous silica. S12. Add cellulose fibers to the NaOH / urea / water solvent system, mix and stir at low temperature to dissolve, then add CaCl2, and stir and react at room temperature to obtain a cellulose sol. S13. Add hollow mesoporous silica to the cellulose sol and stir evenly to coat a layer of cellulose sol on the surface of the hollow mesoporous silica. Filter to obtain cellulose / silica composite microspheres, and freeze-dry the composite microspheres to obtain porous cellulose / silica composite microspheres. S14. Calcinate the porous cellulose / silica composite microspheres prepared in step S13 under the protection of argon to obtain porous carbon / silica composite microspheres.

2. The high-toughness impact-resistant PP material according to claim 1, wherein: In step S5, the temperature of the warm water is 30-40 °C, and the time of ultrasonic oscillation is 10-30 min.

3. The high-toughness impact-resistant PP material according to claim 1, wherein: In step S11, the volume ratio of tetraethyl orthosilicate, anhydrous ethanol, polyethylene glycol 400 and hydrochloric acid solution is 12-16:25-40:2-3:100-120, the sintering temperature is 550-650 °C, and the sintering time is 5-10 h.

4. The high-toughness impact-resistant PP material according to claim 3, characterized in that: In step S12, the content of CaCl2 in the cellulose sol is 0.5-1.2 wt%.

5. The high-toughness impact-resistant PP material according to claim 3, characterized in that: In the step S14, the calcination temperature is 800 - 900 °C and the time is 2 - 3 h.