A modified composite material containing recycled polycarbonate and preparation method thereof

Abstract

The present invention discloses a modified composite material containing recycled polycarbonate and a preparation method thereof, and belongs to the technical field of composite materials. The present invention utilizes 4-((1S)-1-amino-2-hydroxyethyl)-2-methylbenzoic acid and benzoyl chloride to undergo an amidation reaction, and then synthesizes a carboxyl-containing oxazoline with p-toluenesulfonyl chloride. A tertiary amine compound containing oxazoline is synthesized by utilizing an esterification reaction between the carboxyl group on the carboxyl-containing oxazoline and the hydroxyl group on 3-dimethylamino-1,2-propylene glycol. Then, decane bromide is introduced into the tertiary amine compound to synthesize a quaternary ammonium salt containing oxazoline. Maleic anhydride is grafted onto ethylene propylene diene monomer rubber, and a ring-opening reaction is generated between maleic anhydride and oxazoline to graft the quaternary ammonium salt onto the ethylene propylene diene monomer rubber. Maleic anhydride-grafted styrene is used as a compatibilizer, and the quaternary ammonium salt-modified ethylene propylene diene monomer rubber is melt-blended with polycarbonate to obtain a modified composite material with excellent mechanical properties and antibacterial properties.

Description

Technical Field

[0001] The present invention relates to the technical field of composite materials, in particular to a modified composite material containing recycled polycarbonate and a preparation method thereof. Background Art

[0002] Polycarbonate (PC), a carbonate-based polymer, boasts excellent properties such as impact resistance, dimensional stability, and electrical insulation. As an engineering plastic, it is widely used in various fields. With the continuous increase in production and demand, a large amount of waste is generated. Due to its resistance to degradation in nature, existing recycling methods have their own shortcomings. Therefore, finding an effective way to recycle polycarbonate waste is essential.

[0003] Polycarbonate has high melt viscosity, is prone to stress cracking, and is difficult to process and shape. In addition, during storage, processing, and daily use, polycarbonate is susceptible to aging and degradation due to the effects of heat, light, and oxygen, which further seriously affects the performance of recycled plastics.

[0004] Therefore, it is necessary to modify the recycled polycarbonate plastic to obtain plastic raw materials with better performance. Summary of the Invention

[0005] In response to the above-mentioned problems existing in the prior art, the purpose of the present invention is to provide a modified composite material containing recycled polycarbonate and a preparation method thereof, which improves the notch sensitivity and stress cracking resistance of polycarbonate. At the same time, the quaternary ammonium salt imparts antibacterial properties to polycarbonate, thereby expanding its application range.

[0006] In order to solve the above problems, the technical solutions adopted by the present invention are as follows:

[0007] A method for preparing a modified composite material containing recycled polycarbonate,

[0008] The carboxyl group on the carboxyl oxazoline is esterified with the hydroxyl group on 3-dimethylamino-1,2-propylene glycol to synthesize a tertiary amine compound containing oxazoline, and then decane bromide is introduced into the tertiary amine compound to synthesize a quaternary ammonium salt containing oxazoline;

[0009] Grafting EPDM rubber with maleic anhydride to obtain maleic anhydride-modified EPDM rubber;

[0010] The quaternary ammonium salt-modified EPDM rubber is obtained by using maleic anhydride-modified EPDM rubber and a quaternary ammonium salt containing oxazoline to undergo a ring-opening reaction, and the quaternary ammonium salt is grafted onto the EPDM rubber.

[0011] The modified composite material is obtained by melt-blending quaternary ammonium salt-modified ethylene propylene diene monomer rubber and recycled polycarbonate using maleic anhydride grafted styrene as a compatibilizer.

[0012] Preferably, the method comprises the following steps:

[0013] (1) Dissolve carboxyl oxazoline, 3-dimethylamino-1,2-propylene glycol and p-toluenesulfonic acid in anhydrous xylene, react at 140-160°C for 5-15 hours, transfer the mixture to a separatory funnel, wash with water, dry the organic layer with anhydrous magnesium sulfate, filter and rotary evaporate, add bromodecane to the rotary evaporated solution, react at 60-80°C for 6-10 hours, and cool to 20-30°C after the reaction to obtain a quaternary ammonium salt containing oxazoline;

[0014] (2) Add EPDM rubber and maleic anhydride to xylene, stir and dissolve at 40-70°C, then heat to 90-110°C, add benzoyl peroxide xylene solution dropwise, react for 1-3 hours, and cool to obtain maleic anhydride-modified EPDM rubber;

[0015] (3) mixing 50-80 parts by mass of a dried quaternary ammonium salt containing oxazoline and 40-70 parts by mass of dried maleic anhydride-modified EPDM rubber, melt-extruding and granulating the mixture using a twin-screw extruder, and drying the pellets to obtain a quaternary ammonium salt-modified EPDM rubber;

[0016] (4) 20-40 parts by weight of quaternary ammonium salt modified EPDM rubber, 4-15 parts by weight of maleic anhydride grafted styrene compatibilizer, and 60-80 parts by weight of recycled polycarbonate are mixed evenly, put into a twin-screw extruder for melt extrusion and granulation, and then a standard sample is made on an injection molding machine to obtain a modified composite material containing recycled polycarbonate.

[0017] Preferably, the mass ratio of carboxy oxazoline, 3-dimethylamino-1,2-propylene glycol, p-toluenesulfonic acid and bromodecane in step (1) is 250-300:80-120:1-2:230-280.

[0018] Preferably, in step (2), the mass ratio of EPDM rubber, maleic anhydride and benzoyl peroxide is 100:3-8:0.5-1.

[0019] Preferably, the preparation method of the carboxyl-containing oxazoline is: 4-((1S)-1-amino-2-hydroxyethyl)-2-methylbenzoic acid and benzoyl chloride undergo an amidation reaction, and then the reaction is reacted with p-toluenesulfonyl chloride to synthesize the carboxyl-containing oxazoline.

[0020] Preferably, 4-((1S)-1-amino-2-hydroxyethyl)-2-methylbenzoic acid and sodium bicarbonate are dissolved in anhydrous tetrahydrofuran, and a tetrahydrofuran solution of benzoyl chloride is added dropwise with stirring in a water bath at 0-4°C, and the reaction is carried out at 20-30°C for 2-6 hours, followed by rotary evaporation under reduced pressure. The residue is dispersed in deionized water and extracted with dichloromethane. The organic layers are combined and dried over anhydrous magnesium sulfate, filtered, rotary evaporated under reduced pressure, and vacuum dried. The obtained product is dissolved in dichloroethane, and anhydrous triethylamine and p-toluenesulfonyl chloride are added dropwise with stirring. The reaction is carried out at 0-4°C for 6-10 hours. After the reaction is completed, the temperature is raised to 20-30°C, and rotary evaporation is carried out under reduced pressure to obtain the carboxyl-containing oxazoline.

[0021] Preferably, the molar ratio of 4-((1S)-1-amino-2-hydroxyethyl)-2-methylbenzoic acid, sodium bicarbonate, benzoyl chloride, anhydrous triethylamine and p-toluenesulfonyl chloride is 30-35:45-53:30-35:250-300:20-30.

[0022] Preferably, the preparation method of recycled polycarbonate is as follows: the recycled optical disc is cut into pieces, immersed in a chemical eluent, and oscillated at a constant temperature of 70-90°C for 30-40 minutes to obtain a polycarbonate base disc, the base disc is dissolved in 1,2-dichloroethane, and stirred at a constant temperature of 40-60°C for 50-80 minutes under sealing, and then filtered, the filter residue is discarded, anhydrous ethanol is added to the filtrate, and the mixture is oscillated at 20-30°C for 30-90 minutes, and then allowed to stand for 3-8 hours, and filtered to obtain coarse polycarbonate particles, and the coarse particles are manually kneaded with ascorbic acid and dibutyl phthalate to obtain recycled polycarbonate.

[0023] Preferably, the mass ratio of the polycarbonate base disk to 1,2-dichloroethane is 1:10-20.

[0024] Preferably, the mass ratio of the polycarbonate coarse particles, ascorbic acid and plasticizer dibutyl phthalate is 10:1.3-2:6-13.

[0025] Compared with the prior art, the present invention has the following beneficial effects:

[0026] (1) The present invention introduces oxazoline into quaternary ammonium salt, utilizes the ring-opening reaction of oxazoline and maleic anhydride to graft the quaternary ammonium salt onto EPDM rubber, and then blends it with polycarbonate to obtain a modified composite material of polycarbonate with excellent mechanical properties and antibacterial properties.

[0027] (2) The present invention uses recycled polycarbonate plastic as the source of polycarbonate, which is beneficial to reducing costs and protecting the environment.

[0028] (3) The present invention uses 4-((1S)-1-amino-2-hydroxyethyl)-2-methylbenzoic acid and benzoyl chloride as reactants to undergo an amidation reaction, which is then reacted with p-toluenesulfonyl chloride to synthesize a new type of carboxyl-containing oxazoline. The carboxyl group on the carboxyl-containing oxazoline is esterified with the hydroxyl group on 3-dimethylamino-1,2-propylene glycol to synthesize a tertiary amine compound containing oxazoline. Decane bromide is then introduced into the tertiary amine compound to synthesize a quaternary ammonium salt containing oxazoline. Maleic anhydride is grafted onto EPDM rubber, and the quaternary ammonium salt is grafted onto the EPDM rubber through a ring-opening reaction between maleic anhydride and oxazoline, thereby imparting excellent antibacterial properties to the EPDM rubber. Maleic anhydride grafted styrene is used as a compatibilizer, and maleic anhydride reacts with the terminal hydroxyl and terminal carboxyl groups on polycarbonate. Styrene and EPDM rubber are similarly compatible, and quaternary ammonium salt-modified EPDM rubber is melt-blended with polycarbonate. EPDM improves the notch sensitivity and stress cracking of polycarbonate. At the same time, quaternary ammonium salt gives polycarbonate antibacterial properties, expanding its application range. DETAILED DESCRIPTION

[0029] The present invention will be further described below with reference to specific embodiments.

[0030] Source of raw materials:

[0031] EPDM rubber: Korean SK S6090F.

[0032] Maleic anhydride grafted styrene: KS-01, Coais Chemical Co., Ltd.

[0033] The remaining raw materials are commercially available conventional chemicals.

[0034] Example 1

[0035] (1) 60 mmol of 4-((1S)-1-amino-2-hydroxyethyl)-2-methylbenzoic acid and 106 mmol of sodium bicarbonate were dissolved in anhydrous tetrahydrofuran. 70 mmol of a tetrahydrofuran solution of benzoyl chloride was added dropwise while stirring in a water bath at 0°C. The mixture was reacted at 25°C for 2 h, and then evaporated under reduced pressure. The residue was dispersed in deionized water and extracted with dichloromethane. The organic layers were combined and dried over anhydrous magnesium sulfate. The mixture was filtered, evaporated under reduced pressure, and dried in a vacuum. The obtained product was dissolved in dichloroethane. 600 mmol of anhydrous triethylamine and 40 mmol of p-toluenesulfonyl chloride were added dropwise while stirring. The mixture was reacted at 0°C for 8 h. After the reaction, the temperature was raised to 25°C and evaporated under reduced pressure to obtain a carboxyl-containing oxazoline.

[0036] (2) Dissolve 15 g of carboxylic oxazoline, 6 g of 3-dimethylamino-1,2-propylene glycol and 100 mg of p-toluenesulfonic acid in anhydrous xylene. After reacting at 160 °C for 15 h, transfer the mixture to a separatory funnel. After washing with water, dry the organic layer with anhydrous magnesium sulfate, filter and evaporate it. Then add 14 g of bromodecane to the evaporated solution and react at 80 °C for 10 h. After the reaction is completed, cool it to 30 °C to obtain a quaternary ammonium salt containing oxazoline.

[0037] (3) Add 50 g of EPDM rubber and 4 g of maleic anhydride into xylene, stir and dissolve at 40 °C, then heat to 100 °C, add dropwise 0.5 g of benzoyl peroxide in xylene, react for 1 h, and cool to obtain maleic anhydride-modified EPDM rubber.

[0038] (4) The recycled used CDs were cut into pieces and soaked in a chemical eluent prepared by dissolving 3 g of sodium hypochlorite and 2 g of sodium hydroxide in deionized water to a mass fraction of 15%. The mixture was shaken at a constant temperature of 80 °C for 35 min to obtain a polycarbonate base disc. 5 g of the base disc was dissolved in 80 g of 1,2-dichloroethane and stirred at a constant temperature of 50 °C for 75 min under a sealed state. The mixture was then filtered and the residue was discarded. Anhydrous ethanol was added to the filtrate and shaken at 25 °C for 60 min. The mixture was allowed to stand for 5 h and filtered to obtain coarse polycarbonate particles. 100 g of the coarse particles were manually kneaded with 17 g of ascorbic acid and 100 g of dibutyl phthalate to obtain polycarbonate particles.

[0039] (5) 80 parts by mass of dried oxazoline-containing quaternary ammonium salt and 40 parts by mass of dried maleic anhydride-modified EPDM rubber were mixed, melt-extruded and granulated using a twin-screw extruder. After the pellets were dried, quaternary ammonium salt-modified EPDM rubber was obtained. Then, 40 parts by mass of quaternary ammonium salt-modified EPDM rubber was uniformly mixed with 4 parts by mass of maleic anhydride-grafted styrene compatibilizer and 80 parts by mass of polycarbonate, and the mixture was put into a twin-screw extruder for melt-extruded and granulated. Then, a standard sample was made on an injection molding machine to obtain a modified composite material of polycarbonate.

[0040] Example 2

[0041] (1) 70 mmol of 4-((1S)-1-amino-2-hydroxyethyl)-2-methylbenzoic acid and 90 mmol of sodium bicarbonate were dissolved in anhydrous tetrahydrofuran. 60 mmol of a tetrahydrofuran solution of benzoyl chloride was added dropwise while stirring in a water bath at 4°C. The mixture was reacted at 30°C for 2 h, and then evaporated under reduced pressure. The residue was dispersed in deionized water and extracted with dichloromethane. The organic layers were combined and dried over anhydrous magnesium sulfate. The mixture was filtered, evaporated under reduced pressure, and dried in a vacuum. The obtained product was dissolved in dichloroethane. 600 mmol of anhydrous triethylamine and 40 mmol of p-toluenesulfonyl chloride were added dropwise while stirring. The mixture was reacted at 4°C for 6 h. After the reaction, the temperature was raised to 30°C and evaporated under reduced pressure to obtain a carboxyl-containing oxazoline.

[0042] (2) Dissolve 15 g of carboxylic oxazoline, 4 g of 3-dimethylamino-1,2-propylene glycol and 100 mg of p-toluenesulfonic acid in anhydrous xylene, react at 150 ° C for 10 h, transfer the mixture to a separatory funnel, wash with water, dry the organic layer with anhydrous magnesium sulfate, filter and evaporate, add 14 g of bromodecane to the evaporated solution, react at 60 ° C for 8 h, and cool to 25 ° C after the reaction to obtain a quaternary ammonium salt containing oxazoline.

[0043] (3) Add 50 g of EPDM rubber and 2.8 g of maleic anhydride into xylene, stir and dissolve at 50 °C, then heat to 100 °C, add dropwise 0.45 g of benzoyl peroxide in xylene, react for 2 h, and cool to obtain maleic anhydride-modified EPDM rubber.

[0044] (4) Cut the recycled used CDs into pieces and soak them in a chemical eluent prepared by dissolving 3g of sodium hypochlorite and 2g of sodium hydroxide in deionized water to a mass fraction of 10%. Oscillate at 90°C for 30min to obtain a polycarbonate base disc. Dissolve 5g of the base disc in 100g of 1,2-dichloroethane and stir at 40°C for 80min under a sealed state. Filter and discard the filter residue. Add anhydrous ethanol to the filtrate and oscillate at 20°C for 90min. Let it stand for 3h and filter to obtain coarse polycarbonate particles. Manually knead 100g of the coarse particles with 20g of ascorbic acid and 60g of dibutyl phthalate to obtain polycarbonate particles.

[0045] (5) 80 parts by mass of dried oxazoline-containing quaternary ammonium salt and 40 parts by mass of dried maleic anhydride-modified EPDM rubber were mixed, melt-extruded and granulated using a twin-screw extruder. After the pellets were dried, quaternary ammonium salt-modified EPDM rubber was obtained. Then, 40 parts by mass of quaternary ammonium salt-modified EPDM rubber was uniformly mixed with 4 parts by mass of maleic anhydride-grafted styrene compatibilizer and 80 parts by mass of polycarbonate, and the mixture was put into a twin-screw extruder for melt-extruded and granulated. Then, a standard sample was made on an injection molding machine to obtain a modified composite material of polycarbonate.

[0046] Example 3

[0047] (1) 60 mmol of 4-((1S)-1-amino-2-hydroxyethyl)-2-methylbenzoic acid and 90 mmol of sodium bicarbonate were dissolved in anhydrous tetrahydrofuran. 60 mmol of a tetrahydrofuran solution of benzoyl chloride was added dropwise while stirring in a water bath at 0°C. The mixture was reacted at 20°C for 2 h, and then evaporated under reduced pressure. The residue was dispersed in deionized water and extracted with dichloromethane. The organic layers were combined and dried over anhydrous magnesium sulfate. The mixture was filtered, evaporated under reduced pressure, and dried in a vacuum. The obtained product was dissolved in dichloroethane. 500 mmol of anhydrous triethylamine and 40 mmol of p-toluenesulfonyl chloride were added dropwise while stirring. The mixture was reacted at 0°C for 6 h. After the reaction, the temperature was raised to 20°C and evaporated under reduced pressure to obtain a carboxyl-containing oxazoline.

[0048] (2) Dissolve 12.5 g of carboxylic oxazoline, 6 g of 3-dimethylamino-1,2-propylene glycol and 50 mg of p-toluenesulfonic acid in anhydrous xylene, react at 160 ° C for 5 h, transfer the mixture to a separatory funnel, wash with water, dry the organic layer with anhydrous magnesium sulfate, filter and evaporate, add 14 g of bromodecane to the evaporated solution, react at 60 ° C for 10 h, and cool to 20 ° C after the reaction to obtain a quaternary ammonium salt containing oxazoline.

[0049] (3) Add 50 g of EPDM rubber and 4 g of maleic anhydride into xylene, stir and dissolve at 40 °C, then heat to 110 °C, add dropwise 0.25 g of benzoyl peroxide in xylene, react for 3 h, and cool to obtain maleic anhydride-modified EPDM rubber.

[0050] (4) Cut the recycled used CDs into pieces and soak them in a chemical eluent prepared by dissolving 3g of sodium hypochlorite and 2g of sodium hydroxide in deionized water to a mass fraction of 15%. Oscillate at 90°C for 30min to obtain a polycarbonate base disc. Dissolve 5g of the base disc in 100g of 1,2-dichloroethane and stir at 40°C for 80min under a sealed state. Filter and discard the filter residue. Add anhydrous ethanol to the filtrate and oscillate at 25°C for 30min. Let it stand for 8h and filter to obtain coarse polycarbonate particles. Manually knead 100g of the coarse particles with 13g of ascorbic acid and 110g of dibutyl phthalate to obtain polycarbonate particles.

[0051] (5) 80 parts by mass of dried oxazoline-containing quaternary ammonium salt and 70 parts by mass of dried maleic anhydride-modified EPDM rubber were mixed, melt-extruded and granulated using a twin-screw extruder. After the pellets were dried, quaternary ammonium salt-modified EPDM rubber was obtained. Then, 40 parts by mass of quaternary ammonium salt-modified EPDM rubber was uniformly mixed with 15 parts by mass of maleic anhydride-grafted styrene compatibilizer and 80 parts by mass of polycarbonate, and the mixture was put into a twin-screw extruder for melt-extruded and granulated. Then, a standard sample was made on an injection molding machine to obtain a modified composite material of polycarbonate.

[0052] Example 4

[0053] (1) Dissolve 70 mmol of 4-((1S)-1-amino-2-hydroxyethyl)-2-methylbenzoic acid and 106 mmol of sodium bicarbonate in anhydrous tetrahydrofuran, add 70 mmol of benzoyl chloride in tetrahydrofuran dropwise while stirring in a water bath at 4°C, react at 30°C for 6 h, and then evaporate under reduced pressure. Disperse the residue in deionized water and extract with dichloromethane. Combine the organic layers and dry them over anhydrous magnesium sulfate. Then filter and evaporate under reduced pressure and vacuum dry. Dissolve the obtained product in dichloroethane, add 600 mmol of anhydrous triethylamine and 60 mmol of p-toluenesulfonyl chloride dropwise while stirring, and react at 4°C for 10 h. After the reaction, heat to 30°C and evaporate under reduced pressure to obtain carboxyl-containing oxazoline.

[0054] (2) 14 g of carboxylic oxazoline, 5 g of 3-dimethylamino-1,2-propylene glycol and 80 mg of p-toluenesulfonic acid were dissolved in anhydrous xylene and reacted at 150 °C for 10 h. The mixture was transferred to a separatory funnel and washed with water. The organic layer was dried over anhydrous magnesium sulfate, filtered and rotary evaporated. 13 g of bromodecane was added to the rotary evaporated solution and reacted at 70 °C for 8 h. After the reaction was completed, the temperature was lowered to 25 °C to obtain a quaternary ammonium salt containing oxazoline.

[0055] (3) Add 50 g of EPDM rubber and 4 g of maleic anhydride into xylene, stir and dissolve at 70 °C, then heat to 110 °C, add dropwise 0.5 g of benzoyl peroxide in xylene, react for 3 h, and cool to obtain maleic anhydride-modified EPDM rubber.

[0056] (4) Cut the recycled used CDs into pieces and soak them in a chemical eluent prepared by dissolving 3g of sodium hypochlorite and 2g of sodium hydroxide in deionized water to a mass fraction of 20%. Oscillate at 90°C for 40min to obtain a polycarbonate base disc. Dissolve 5g of the base disc in 100g of 1,2-dichloroethane and stir at 60°C for 80min under a sealed state. Filter and discard the filter residue. Add anhydrous ethanol to the filtrate and oscillate at 30°C for 90min. Let it stand for 8h and filter to obtain coarse polycarbonate particles. Manually knead 100g of the coarse particles with 20g of ascorbic acid and 130g of dibutyl phthalate to obtain polycarbonate particles.

[0057] (5) 50 parts by mass of dried oxazoline-containing quaternary ammonium salt and 40 parts by mass of dried maleic anhydride-modified EPDM rubber were mixed, melt-extruded and granulated using a twin-screw extruder. After the pellets were dried, quaternary ammonium salt-modified EPDM rubber was obtained. Then, 20 parts by mass of quaternary ammonium salt-modified EPDM rubber was uniformly mixed with 4 parts by mass of maleic anhydride-grafted styrene compatibilizer and 60 parts by mass of polycarbonate, and the mixture was put into a twin-screw extruder for melt-extruded and granulated. Then, a standard sample was made on an injection molding machine to obtain a modified composite material of polycarbonate.

[0058] Example 5

[0059] (1) 65 mmol of 4-((1S)-1-amino-2-hydroxyethyl)-2-methylbenzoic acid and 95 mmol of sodium bicarbonate were dissolved in anhydrous tetrahydrofuran. 65 mmol of a tetrahydrofuran solution of benzoyl chloride was added dropwise while stirring in a water bath at 2°C. The mixture was reacted at 25°C for 4 h, and then evaporated under reduced pressure. The residue was dispersed in deionized water and extracted with dichloromethane. The organic layers were combined and dried over anhydrous magnesium sulfate. The mixture was filtered, evaporated under reduced pressure, and dried in a vacuum. The obtained product was dissolved in dichloroethane. 550 mmol of anhydrous triethylamine and 50 mmol of p-toluenesulfonyl chloride were added dropwise while stirring. The mixture was reacted at 2°C for 8 h. After the reaction, the temperature was raised to 25°C and evaporated under reduced pressure to obtain a carboxyl-containing oxazoline.

[0060] (2) Dissolve 12.5 g of carboxylic oxazoline, 4 g of 3-dimethylamino-1,2-propylene glycol and 50 mg of p-toluenesulfonic acid in anhydrous xylene, react at 140 ° C for 5 h, transfer the mixture to a separatory funnel, wash with water, dry the organic layer with anhydrous magnesium sulfate, filter and evaporate, add 11.5 g of bromodecane to the evaporated solution, react at 60 ° C for 6 h, and cool to 20 ° C after the reaction to obtain a quaternary ammonium salt containing oxazoline.

[0061] (3) Add 50 g of EPDM rubber and 1.5 g of maleic anhydride to xylene, stir and dissolve at 40 °C, then heat to 90 °C, add 0.25 g of benzoyl peroxide in xylene solution dropwise, react for 1 h, and cool to obtain maleic anhydride-modified EPDM rubber.

[0062] (4) Cut the recycled used CDs into pieces and soak them in a chemical eluent prepared by dissolving 3g of sodium hypochlorite and 2g of sodium hydroxide in deionized water to a mass fraction of 10%. Oscillate at 70°C for 30min to obtain a polycarbonate base disc. Dissolve 5g of the base disc in 50g of 1,2-dichloroethane and stir at 40°C for 50min under a sealed state. Filter and discard the residue. Add anhydrous ethanol to the filtrate and oscillate at 20°C for 30min. Let it stand for 3h and filter to obtain coarse polycarbonate particles. Manually knead 100g of the coarse particles with 13g of ascorbic acid and 60g of dibutyl phthalate to obtain polycarbonate particles.

[0063] (5) 75 parts by mass of dried oxazoline-containing quaternary ammonium salt and 55 parts by mass of dried maleic anhydride-modified EPDM rubber were mixed, melt-extruded and granulated using a twin-screw extruder. After the pellets were dried, quaternary ammonium salt-modified EPDM rubber was obtained. Then, 30 parts by mass of quaternary ammonium salt-modified EPDM rubber was uniformly mixed with 9 parts by mass of maleic anhydride-grafted styrene compatibilizer and 70 parts by mass of polycarbonate. The mixtures were put into a twin-screw extruder for melt-extruded and granulated, and then standard samples were made on an injection molding machine to obtain a modified composite material of polycarbonate.

[0064] Comparative Example 1

[0065] (1) The recycled used CDs were cut into pieces and soaked in a chemical eluent prepared by dissolving 3 g of sodium hypochlorite and 2 g of sodium hydroxide in deionized water to a mass fraction of 15%. The mixture was shaken at 80°C for 30 min to obtain a polycarbonate base disc. 5 g of the base disc was dissolved in 75 g of 1,2-dichloroethane and stirred at 50°C for 40 min under a sealed state. The mixture was then filtered and the residue was discarded. Anhydrous ethanol was added to the filtrate and shaken at 25°C for 60 min. The mixture was allowed to stand for 5 h and filtered to obtain coarse polycarbonate particles. 100 g of the coarse particles were manually kneaded with 17 g of ascorbic acid and 100 g of dibutyl phthalate to obtain polycarbonate particles.

[0066] (2) 30 parts by mass of EPDM rubber, 9 parts by mass of maleic anhydride grafted styrene compatibilizer, and 70 parts by mass of polycarbonate were mixed evenly, put into a twin-screw extruder for melt extrusion and granulation, and then made into a standard sample on an injection molding machine to obtain a modified composite material of polycarbonate.

[0067] The product's tensile strength was tested according to GB / T1040.2-2022, its flexural strength was tested according to GB / T9341-2008, its melt flow rate was tested according to GB / T3682.2-2018, its elongation at break was tested according to ASTMD638, and its antibacterial properties were tested according to GB / T31402-2015. The test results are shown in Table 1.

[0068] Table 1 Product performance test results

[0069]

[0070] As can be seen from Table 1, the products prepared in each embodiment have a tensile strength of about 50 MPa, a flexural strength of about 90 MPa, an elongation at break of about 60%, and an antibacterial activity value of about 5.0, which are significantly higher than the data of the comparative example, indicating that the mechanical properties of the composite material are significantly improved after the EPDM rubber and polycarbonate are blended, and the introduction of quaternary ammonium salt also greatly improves the antibacterial properties of polycarbonate.

Claims

1. A method for preparing a modified composite material containing recycled polycarbonate, characterized in that: The carboxyl group on the carboxyl oxazoline is esterified with the hydroxyl group on 3-dimethylamino-1,2-propylene glycol to synthesize a tertiary amine compound containing oxazoline, and then decane bromide is introduced into the tertiary amine compound to synthesize a quaternary ammonium salt containing oxazoline; Grafting EPDM rubber with maleic anhydride to obtain maleic anhydride-modified EPDM rubber; The quaternary ammonium salt-modified EPDM rubber is obtained by using maleic anhydride-modified EPDM rubber and a quaternary ammonium salt containing oxazoline to undergo a ring-opening reaction, and the quaternary ammonium salt is grafted onto the EPDM rubber. Using maleic anhydride grafted styrene as a compatibilizer, quaternary ammonium salt modified EPDM rubber and recycled polycarbonate are melt-blended to obtain the modified composite material; The preparation method of the carboxyl-containing oxazoline comprises the following steps: using 4-((1S)-1-amino-2-hydroxyethyl)-2-methylbenzoic acid and benzoyl chloride to undergo an amidation reaction, and then reacting the reaction mixture with p-toluenesulfonyl chloride to synthesize the carboxyl-containing oxazoline.

2. The preparation method according to claim 1, wherein: The following steps are involved: (1) Dissolve carboxyl oxazoline, 3-dimethylamino-1,2-propylene glycol and p-toluenesulfonic acid in anhydrous xylene, react at 140-160°C for 5-15 hours, transfer the mixture to a separatory funnel, wash with water, dry the organic layer with anhydrous magnesium sulfate, filter and rotary evaporate, add bromodecane to the rotary evaporated solution, react at 60-80°C for 6-10 hours, and cool to 20-30°C after the reaction to obtain a quaternary ammonium salt containing oxazoline; (2) Add EPDM rubber and maleic anhydride to xylene, stir and dissolve at 40-70°C, then heat to 90-110°C, add benzoyl peroxide xylene solution dropwise, react for 1-3 hours, and cool to obtain maleic anhydride-modified EPDM rubber; (3) mixing 50-80 parts by mass of a dried quaternary ammonium salt containing oxazoline and 40-70 parts by mass of dried maleic anhydride-modified EPDM rubber, melt-extruding and granulating the mixture using a twin-screw extruder, and drying the pellets to obtain a quaternary ammonium salt-modified EPDM rubber; (4) 20-40 parts by weight of quaternary ammonium salt modified EPDM rubber, 4-15 parts by weight of maleic anhydride grafted styrene compatibilizer, and 60-80 parts by weight of recycled polycarbonate are mixed evenly, put into a twin-screw extruder for melt extrusion and granulation, and then a standard sample is made on an injection molding machine to obtain a modified composite material containing recycled polycarbonate.

3. The preparation method according to claim 2, wherein: The mass ratio of carboxy oxazoline, 3-dimethylamino-1,2-propylene glycol, p-toluenesulfonic acid and bromodecane in step (1) is 250-300:80-120:1-2:230-280.

4. The preparation method according to claim 2, wherein: In the step (2), the mass ratio of EPDM rubber, maleic anhydride and benzoyl peroxide is 100:3-8:0.5-1.

5. The preparation method according to claim 1, wherein: 4-((1S)-1-amino-2-hydroxyethyl)-2-methylbenzoic acid and sodium bicarbonate are dissolved in anhydrous tetrahydrofuran, and a tetrahydrofuran solution of benzoyl chloride is added dropwise with stirring in a water bath at 0-4°C. The mixture is reacted at 20-30°C for 2-6 hours, and then evaporated under reduced pressure. The residue is dispersed in deionized water and extracted with dichloromethane. The organic layers are combined and dried over anhydrous magnesium sulfate, filtered, evaporated under reduced pressure, and dried in vacuo. The obtained product is dissolved in dichloroethane, and anhydrous triethylamine and p-toluenesulfonyl chloride are added dropwise with stirring. The mixture is reacted at 0-4°C for 6-10 hours. After the reaction, the temperature is raised to 20-30°C, and evaporated under reduced pressure to obtain a carboxyl-containing oxazoline.

6. The preparation method according to claim 5, characterized in that: The molar ratio of 4-((1S)-1-amino-2-hydroxyethyl)-2-methylbenzoic acid, sodium bicarbonate, benzoyl chloride, anhydrous triethylamine and p-toluenesulfonyl chloride is 30-35:45-53:30-35:250-300:20-30.

7. The preparation method according to claim 1 or 2, characterized in that: The preparation method of recycled polycarbonate comprises the following steps: cutting the recycled optical disc into pieces, soaking the pieces in a chemical eluent, and oscillating the pieces at a constant temperature of 70-90°C for 30-40 minutes to obtain a polycarbonate base disc; dissolving the base disc in 1,2-dichloroethane, and stirring the pieces at a constant temperature of 40-60°C for 50-80 minutes under sealing; filtering the pieces, and discarding the filter residue; adding anhydrous ethanol to the filtrate, and oscillating the pieces at 20-30°C for 30-90 minutes, and then letting the pieces stand for 3-8 hours; filtering the pieces to obtain coarse polycarbonate particles; and manually kneading the coarse particles with ascorbic acid and dibutyl phthalate to obtain recycled polycarbonate.

8. The preparation method according to claim 7, characterized in that: The mass ratio of the polycarbonate base disk to 1,2-dichloroethane is 1:10-20.

9. The preparation method according to claim 7, characterized in that: The mass ratio of the polycarbonate coarse particles, ascorbic acid and plasticizer dibutyl phthalate is 10:1.3-2:6-13.

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