Degradable PA6 composite modified plastic

Abstract

The invention relates to a degradable PA6 composite modified plastic, and belongs to the technical field of composite materials. According to the invention, the modifier with double bonds in the structure is prepared and is used for modifying PBAT, so that the problem of non-uniform distribution of a polar additive in PBAT-PA6 composite plastic is effectively solved, and good antibacterial performance and ultraviolet aging resistance are provided for the composite plastic; the modifier can also improve the polarity of the modified PBAT, and the quaternary ammonium salt structure in the structure and the polar amido bond in the PA6 are utilized to form ion-dipole interaction to enhance the binding power between the modified PBAT phase and the PA6 phase, so that the compatibility between the modified PBAT and the PA6 is improved, and the overall mechanical property of the PBAT-PA6 composite plastic is further improved.

Description

Technical Field

[0001] This invention belongs to the field of composite material technology, specifically, it relates to a biodegradable PA6 composite modified plastic, and more specifically, it relates to a PA6-PBAT composite plastic. Background Technology

[0002] PBAT, or polybutylene adipate terephthalate, is a petroleum-based biodegradable plastic. In the natural environment, PBAT can be completely decomposed into carbon dioxide and water by microorganisms, without causing pollution to the environment. It also has good ductility, heat resistance and impact resistance, and is widely used in packaging materials and agricultural mulch films.

[0003] Despite the many excellent properties of PBAT, its mechanical and gas barrier properties are relatively poor. These shortcomings can be effectively addressed by blending PBAT with an appropriate amount of PA6 (polyamide 6), and the resulting composite plastic remains biodegradable, showing broad research potential. However, the two materials have significant differences in chemical polarity. PBAT is weakly polar, with ester groups as the main component, while PA6 is a polar polymer containing a large number of amide groups in its molecular chain. Direct blending often results in poor modification. Furthermore, due to the significant polarity difference between the two, polar additives (such as antibacterial agents and UV absorbers) tend to preferentially dissolve and accumulate in the more polar PA6 microregions, severely affecting the overall modification effect of the additives on the composite plastic. To address these technical deficiencies, this invention provides a biodegradable PA6 composite modified plastic. Summary of the Invention

[0004] The purpose of this invention is to provide a biodegradable PA6 composite modified plastic to solve the problems mentioned in the background art.

[0005] The objective of this invention can be achieved through the following technical solutions: A biodegradable PA6 composite modified plastic comprises the following raw materials in parts by weight: 75-85 parts modified PBAT, 15-25 parts polyamide 6, and 0.2-0.4 parts antioxidant; The modified PBAT molecular chain is grafted with the modifier of the present invention, which has a reactive double bond, a pyridyl quaternary ammonium salt structure and an ortho-hydroxybenzophenone structure.

[0006] Furthermore, biodegradable PA6 composite modified plastics can be prepared by the following methods: Modified PBAT, polyamide 6, and antioxidants were mixed and added to a twin-screw extruder for melt extrusion at a temperature of 230–240°C to obtain biodegradable PA6 composite modified plastic.

[0007] Furthermore, the antioxidant used in the step of preparing the biodegradable PA6 composite modified plastic is one of antioxidant 1010, antioxidant 1035, and antioxidant 1076.

[0008] Furthermore, the modified PBAT used in the preparation of the biodegradable PA6 composite modified plastic can be prepared by the following steps: Modified PBAT is obtained by mixing PBAT, modifier, initiator, and antioxidant and then adding the mixture to a twin-screw extruder and melt-extruding it at a temperature of 150-160℃.

[0009] Furthermore, the initiator used in the preparation step of modified PBAT is at least one of benzoyl peroxide and dicumyl peroxide.

[0010] Furthermore, the antioxidant used in the preparation of modified PBAT is antioxidant 168.

[0011] Furthermore, the preferred mass ratio of PBAT, modifier, initiator, and antioxidant used in the preparation step of modified PBAT is 100:3-4:0.15-0.25:0.1.

[0012] Furthermore, the modifier used in the preparation of modified PBAT can be prepared by the following steps: Aromatic acyl chlorides and phenol derivatives are subjected to esterification and Friedel-Crafts rearrangement reactions in sequence to obtain ultraviolet absorbers for later use. Then, olefins are subjected to the Wol-Ziegler reaction to obtain haloolefins. Finally, haloolefins are reacted with ultraviolet absorbers in a quaternary ammonium salt reaction to obtain modifiers.

[0013] Furthermore, the aromatic acyl chloride used in the preparation step of the modifier is one of nicotinic acid chloride and isonicotinic acid chloride, preferably isonicotinic acid chloride.

[0014] Furthermore, the phenol derivative used in the preparation step of the modifier is one of 3-dodecoxyphenol or 4-dodecoxyphenol.

[0015] Furthermore, the olefin used in the preparation step of the modifier is one of 2-methyl-1-dodecene or 2-methyl-1-tetradecene.

[0016] The beneficial effects of this invention are: The modifier prepared by this invention has an o-hydroxybenzophenone structure, which can form reversible intramolecular hydrogen bonds to absorb the energy of ultraviolet light and convert it into heat energy when exposed to ultraviolet light. In addition, the modifier of this invention also has a pyridyl quaternary ammonium salt structure. The pyridyl quaternary ammonium salt not only has good antibacterial properties, but its quaternary ammonium salt structure can also be incorporated into the conjugated system of o-hydroxybenzophenone, significantly enhancing the intramolecular electron donation and electron withdrawal effect, reducing the band gap, enabling the molecule to absorb ultraviolet light with longer wavelengths, achieving a red shift in the absorption spectrum, and fully covering the entire ultraviolet spectrum. Using the modifier of this invention to modify PBAT can effectively improve the overall antibacterial properties and UV aging resistance of PBAT-PA6 composite plastics.

[0017] The modifier prepared by this invention has two long-chain alkyl structures, which have good compatibility with the ester groups in the PBAT molecular chain. The double bond structure can also be grafted into the PBAT molecular chain under the action of an initiator, effectively solving the migration problem of additives in composite modified plastics.

[0018] This invention uses a modifier to modify PBAT, introducing a quaternary ammonium salt structure into the modified PBAT, which enhances the polarity of the modified PBAT. The quaternary ammonium salt structure can also enhance the adhesion between the modified PBAT phase and the PA6 phase by forming ion-dipole interactions with the polar amide bonds in PA6, thereby improving the compatibility between modified PBAT and PA6, and thus improving the overall mechanical properties of the modified PBAT-PA6 composite plastic. It also improves the problem of uneven distribution of polar additives in the modified PBAT-PA6 composite plastic. Detailed Implementation

[0019] The technical solution of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. 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 of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0020] The raw materials used in this invention are not particularly restricted in terms of their source; they can be purchased from the market or prepared using conventional methods known to those skilled in the art.

[0021] The room temperature was 25±5℃.

[0022] Example 1 A biodegradable PA6 composite modified plastic comprises the following raw materials in parts by weight: 75 parts modified PBAT, 15 parts polyamide 6, and 0.2 parts antioxidant 1010; The modified PBAT can be prepared by the following steps: Modified PBAT was obtained by mixing 100 parts PBAT, 3 parts modifier, 0.15 parts benzoyl peroxide, and 0.1 parts antioxidant 168 by weight and then adding the mixture to a twin-screw extruder and melt-extruding at a temperature of 150°C. The modifier is prepared by the following steps: S1. By mass fraction, 2.8 parts of 3-dodecyloxyphenol, 1.2 parts of triethylamine, and 20 parts of dichloromethane were mixed in a three-necked flask equipped with a thermometer and a reflux condenser. A solution prepared by 1.4 parts of nicotinamide chloride and 10 parts of dichloromethane was added dropwise to the three-necked flask at room temperature. After the addition was complete, the mixture was reacted at room temperature for 6 hours. After the reaction was completed, the mixture was cooled to room temperature, and 20 parts of 10% dilute hydrochloric acid were added to the three-necked flask. The organic layer was separated, dried, and the solvent was removed by rotary evaporation to obtain the esterified product. Then, 3.2 parts of the esterified product, 2.2 parts of aluminum trichloride, and 15 parts of o-dichlorobenzene were mixed in a three-necked flask equipped with a thermometer and a reflux condenser. The mixture was reacted at 130°C for 6 hours. After the reaction was completed, the mixture was cooled to room temperature, and 30 parts of 10% dilute hydrochloric acid were added to the three-necked flask. The solvent was then removed by rotary evaporation, and the remaining solid was recrystallized to obtain the ultraviolet absorber. S2. By mass, 1.8 parts of 2-methyl-1-dodecene, 1.8 parts of N-bromosuccinimide, 0.4 parts of benzoyl peroxide, and 20 parts of carbon tetrachloride were mixed in a three-necked flask equipped with a thermometer and a reflux condenser. The mixture was reacted at 60°C for 10 hours. After the reaction was completed, the solid was separated by filtration. The remaining reaction solution was rotary evaporated to remove the solvent and obtain a haloalkene. S3. By mass, 2.5 parts of ultraviolet absorber, 1.8 parts of haloolefin and 15 parts of acetonitrile were mixed in a three-necked flask equipped with a thermometer and a reflux condenser. The mixture was reacted at 40°C for 48 hours. After the reaction was completed, the solvent was removed by rotary evaporation. The remaining solid was washed with petroleum ether and dried to obtain the modifier. Biodegradable PA6 composite modified plastics are prepared by the following methods: By weight, 75 parts of modified PBAT, 15 parts of polyamide 6, and 0.2 parts of antioxidant 1010 were mixed and added to a twin-screw extruder and melt-extruded at a temperature of 230°C to obtain a biodegradable PA6 composite modified plastic.

[0023] Example 2 A biodegradable PA6 composite modified plastic comprises the following raw materials in parts by weight: 80 parts modified PBAT, 20 parts polyamide 6, and 0.3 parts antioxidant 1035; The modified PBAT can be prepared by the following steps: Modified PBAT was obtained by mixing 100 parts PBAT, 3.5 parts modifier, 0.2 parts dicumyl peroxide, and 0.1 parts antioxidant 168 by weight and then adding the mixture to a twin-screw extruder and melt-extruded at a temperature of 155°C. The modifier is prepared by the following steps: S1. By mass fraction, 2.8 parts of 4-dodecoxyphenol, 1.6 parts of triethylamine, and 20 parts of dichloromethane were mixed in a three-necked flask equipped with a thermometer and a reflux condenser. A solution prepared by 1.4 parts of isonicotinamide chloride and 10 parts of dichloromethane was added dropwise to the three-necked flask at room temperature. After the addition was complete, the mixture was reacted at room temperature for 7 hours. After the reaction was completed, the mixture was cooled to room temperature, and 20 parts of 10% dilute hydrochloric acid were added to the three-necked flask. The organic layer was separated, dried, and the solvent was removed by rotary evaporation to obtain the esterified product. Then, 3.2 parts of the esterified product, 2.4 parts of aluminum trichloride, and 15 parts of o-dichlorobenzene were mixed in a three-necked flask equipped with a thermometer and a reflux condenser. The mixture was reacted at 140°C for 5 hours. After the reaction was completed, the mixture was cooled to room temperature, and 30 parts of 10% dilute hydrochloric acid were added to the three-necked flask. The solvent was then removed by rotary evaporation, and the remaining solid was recrystallized to obtain the ultraviolet absorber. S2. By mass, 2.1 parts of 2-methyl-1-tetradecene, 1.8 parts of N-bromosuccinimide, 0.4 parts of benzoyl peroxide, and 20 parts of carbon tetrachloride were mixed in a three-necked flask equipped with a thermometer and a reflux condenser. The mixture was reacted at 70°C for 8 hours. After the reaction was completed, the solid was separated by filtration. The remaining reaction solution was rotary evaporated to remove the solvent and obtain a haloalkene. S3. By mass, 2.5 parts of ultraviolet absorber, 2.0 parts of haloolefin and 15 parts of acetonitrile are mixed in a three-necked flask equipped with a thermometer and a reflux condenser. The mixture is reacted at 55°C for 24 hours. After the reaction is completed, the solvent is removed by rotary evaporation. The remaining solid is washed with petroleum ether and dried to obtain the modifier. Biodegradable PA6 composite modified plastics are prepared by the following methods: By weight, 80 parts of modified PBAT, 20 parts of polyamide 6, and 0.3 parts of antioxidant 1035 were mixed and added to a twin-screw extruder and melt-extruded at a temperature of 235°C to obtain a biodegradable PA6 composite modified plastic.

[0024] Example 3 A biodegradable PA6 composite modified plastic comprises the following raw materials in parts by weight: 85 parts modified PBAT, 25 parts polyamide 6, and 0.4 parts antioxidant 1076; The modified PBAT can be prepared by the following steps: Modified PBAT was obtained by mixing 100 parts PBAT, 4 parts modifier, 0.25 parts dicumyl peroxide, and 0.1 parts antioxidant 168 by weight and then adding the mixture to a twin-screw extruder and melt-extruding at a temperature of 160°C. The modifier is prepared by the following steps: S1. By mass, 5.6 parts of 3-dodecoxyphenol, 2.4 parts of triethylamine, and 35 parts of dichloromethane were mixed in a three-necked flask equipped with a thermometer and a reflux condenser. A solution prepared from 2.8 parts of isonicotinamide chloride and 15 parts of dichloromethane was added dropwise to the three-necked flask at room temperature. After the addition was complete, the mixture was reacted at room temperature for 8 hours. After the reaction was completed, the mixture was cooled to room temperature, and 30 parts of 10% dilute hydrochloric acid were added to the three-necked flask. The organic layer was separated, dried, and the solvent was removed by rotary evaporation to obtain the esterified product. Then, 6.5 parts of the esterified product, 4.4 parts of aluminum trichloride, and 30 parts of o-dichlorobenzene were mixed in a three-necked flask equipped with a thermometer and a reflux condenser. The mixture was reacted at 150°C for 4 hours. After the reaction was completed, the mixture was cooled to room temperature, and 50 parts of 10% dilute hydrochloric acid were added to the three-necked flask. The solvent was then removed by rotary evaporation, and the remaining solid was recrystallized to obtain the ultraviolet absorber. S2. By mass, 3.6 parts of 2-methyl-1-dodecene, 3.6 parts of N-bromosuccinimide, 0.8 parts of benzoyl peroxide, and 40 parts of carbon tetrachloride were mixed in a three-necked flask equipped with a thermometer and a reflux condenser. The mixture was reacted at 80°C for 6 hours. After the reaction was completed, the solid was separated by filtration. The remaining reaction solution was rotary evaporated to remove the solvent and obtain a haloalkene. S3. By mass, 5.2 parts of ultraviolet absorber, 4.4 parts of haloolefin and 30 parts of acetonitrile were mixed in a three-necked flask equipped with a thermometer and a reflux condenser. The mixture was reacted at 80°C for 6 hours. After the reaction was completed, the solvent was removed by rotary evaporation. The remaining solid was washed with petroleum ether and dried to obtain the modifier. Biodegradable PA6 composite modified plastics are prepared by the following methods: By weight, 85 parts of modified PBAT, 25 parts of polyamide 6, and 0.4 parts of antioxidant 1076 were mixed and added to a twin-screw extruder and melt-extruded at a temperature of 240°C to obtain a biodegradable PA6 composite modified plastic.

[0025] Comparative Example 1 The difference between this comparative example and Example 1 is that PBAT is not modified. Instead, unmodified PBAT is used to replace the modified PBAT in the raw materials, and ultraviolet absorbers and antibacterial agents are added in proportion.

[0026] A biodegradable PA6 composite modified plastic comprises the following raw materials in parts by weight: 75 parts PBAT, 15 parts polyamide 6, 0.2 parts antioxidant 1010, 1 part 2-hydroxy-4-n-octyloxybenzophenone, and 1.25 parts dimethylbenzyl alkyl ammonium chloride. Biodegradable PA6 composite modified plastics are prepared by the following methods: By weight, 75 parts PBAT, 15 parts polyamide 6, 1 part 2-hydroxy-4-n-octyloxybenzophenone, 1.25 parts dimethyl benzyl alkyl ammonium chloride, and 0.2 parts antioxidant 1010 were mixed and added to a twin-screw extruder and melt-extruded at a temperature of 230°C to obtain biodegradable PA6 composite modified plastic.

[0027] Experimental Example The biodegradable PA6 composite modified plastics in Examples 1-3 and Comparative Example 1 were subjected to the following performance tests, and the test results are shown in Table 1 and Table 2. Mechanical property testing: The tensile strength and elongation at break of each component of the biodegradable PA6 composite modified plastic were tested in accordance with the national standard GB / T 1040.2-2006 "Determination of tensile properties of plastics". UV aging test: A 500-hour accelerated UV aging test was conducted according to the national standard GB / T16422.3 "Laboratory Light Exposure Test Methods for Plastics - Part 3: Fluorescent UV Lamp". Then, the tensile strength and elongation at break of each component of the biodegradable PA6 composite modified plastic were tested according to the national standard GB / T 1040.2-2006 "Determination of Tensile Properties of Plastics". The tensile strength retention rate and elongation at break retention rate of each component of the biodegradable PA6 composite modified plastic after accelerated aging were calculated. Antibacterial performance test: The antibacterial rate of each component of the biodegradable PA6 composite modified plastic against Escherichia coli and Staphylococcus aureus was tested in accordance with the national standard GB / T 31402-2023 "Determination of antibacterial activity of plastics and other non-porous materials".

[0028]

[0029]

[0030] As can be seen from Tables 1 and 2, the modifier of the present invention effectively improves the compatibility between PBAT and PA6, thereby improving the overall mechanical properties of the composite material. Compared with the modification method of directly adding antibacterial agents and ultraviolet absorbers, the modifier of the present invention can better improve the overall UV aging resistance and antibacterial properties of the material.

[0031] The above description of the disclosed embodiments enables those skilled in the art to make or use the invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention. Therefore, the invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A biodegradable PA6 composite modified plastic, characterized in that, It contains the following raw materials: modified PBAT, polyamide 6, and antioxidants; Among them, the modified PBAT molecular chain is grafted with a modifier, which has a reactive double bond, a pyridyl quaternary ammonium salt structure and an o-hydroxybenzophenone structure.

2. The biodegradable PA6 composite modified plastic according to claim 1, characterized in that, It contains the following parts by weight of raw materials: 75-85 parts modified PBAT, 15-25 parts polyamide 6, and 0.2-0.4 parts antioxidant.

3. The biodegradable PA6 composite modified plastic according to claim 1, characterized in that, Biodegradable PA6 composite modified plastics are prepared by the following methods: Modified PBAT, polyamide 6, and antioxidants were mixed and added to a twin-screw extruder for melt extrusion at a temperature of 230–240°C to obtain biodegradable PA6 composite modified plastic.

4. The biodegradable PA6 composite modified plastic according to claim 3, characterized in that, The antioxidant used in the preparation of biodegradable PA6 composite modified plastic is one of antioxidant 1010, antioxidant 1035, and antioxidant 1076.

5. The biodegradable PA6 composite modified plastic according to claim 3, characterized in that, The modified PBAT used in the preparation of biodegradable PA6 composite modified plastics is prepared by the following steps: Modified PBAT is obtained by mixing PBAT, modifier, initiator, and antioxidant and then adding the mixture to a twin-screw extruder and melt-extruding it at a temperature of 150-160℃.

6. The biodegradable PA6 composite modified plastic according to claim 5, characterized in that, The initiator used in the preparation of modified PBAT is at least one of benzoyl peroxide and dicumyl peroxide.

7. The biodegradable PA6 composite modified plastic according to claim 5, characterized in that, The antioxidant used in the preparation of modified PBAT is antioxidant 168.

8. The biodegradable PA6 composite modified plastic according to claim 5, characterized in that, The mass ratio of PBAT, modifier, initiator, and antioxidant used in the preparation of modified PBAT is 100:3-4:0.15-0.25:0.

1.

9. The biodegradable PA6 composite modified plastic according to claim 8, characterized in that, The modifier used in the preparation of modified PBAT is prepared by the following steps: Aromatic acyl chlorides and phenol derivatives are subjected to esterification and Friedel-Crafts rearrangement reactions in sequence to obtain ultraviolet absorbers for later use. Then, olefins are subjected to the Wol-Ziegler reaction to obtain haloolefins. Finally, haloolefins are reacted with ultraviolet absorbers in a quaternary ammonium salt reaction to obtain modifiers.

10. The biodegradable PA6 composite modified plastic according to claim 9, characterized in that, The aromatic acyl chloride used in the preparation of the modifier is one of nicotinic acid chloride and isonicotinic acid chloride; the phenol derivative used in the preparation of the modifier is one of 3-dodecoxyphenol and 4-dodecoxyphenol; and the olefin used in the preparation of the modifier is one of 2-methyl-1-dodecene and 2-methyl-1-tetradecene.

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