Anti-aging degradable plastic and preparation method thereof

Abstract

The invention relates to the technical field of plastics, and discloses an anti-aging degradable plastic and a preparation method thereof. The preparation method comprises the following steps: uniformly mixing 100 parts by weight of polyethylene glycol terephthalate, 50-100 parts by weight of nylon resin, 20-60 parts by weight of modified cellulose and the like, carrying out melt extrusion pelletizing, and carrying out injection molding to obtain the anti-aging degradable plastic. A polymer molecular chain containing a benzoate group and an amido bond is grafted in a cellulose molecular chain, the compatibility between the cellulose molecular chain and PET and nylon resin is good, microcrystalline cellulose is uniformly dispersed in a composite plastic matrix, good tensile strength and bending strength can be maintained, cellulose has better biodegradability, and the composite plastic can be widely applied to the field of plastic materials. The improvement of the biodegradation rate and the degradability of the plastic is facilitated.

Description

Technical Field

[0001] This invention relates to the field of plastics technology, specifically to an anti-aging biodegradable plastic and its preparation method. Background Technology

[0002] Polyethylene terephthalate (PET) and nylon resin both exhibit good heat resistance and excellent high-temperature processing properties. Furthermore, PET is biodegradable and environmentally friendly. The alloy materials formed by combining these two materials possess advantages such as good mechanical strength, flexibility, and low water absorption. However, the poor biodegradability of nylon resin can negatively impact the biodegradability of the composite material.

[0003] Cellulose is the most abundant polymer material in nature. It is biodegradable, has high mechanical strength, and good heat resistance, and has wide applications in plastics, fibers, and other materials. Chinese patent CN115403850B discloses a high-barrier material and its preparation method. It utilizes silane coupling agents and hydrophobic agents to treat nano-cellulose, and then composites it with PET (polyethylene terephthalate) and high-density polyethylene. The resulting composite material exhibits good high-barrier and biodegradable properties; however, the poor compatibility between cellulose and PET is detrimental to improving the material's mechanical properties. Summary of the Invention

[0004] To address the shortcomings of existing technologies, this invention provides an anti-aging biodegradable plastic and its preparation method, which solves the problem of poor mechanical properties of polyester-nylon composite materials, and also has good anti-aging and biodegradable properties.

[0005] To solve the above-mentioned technical problems, the technical solution adopted by the present invention is: a method for preparing anti-aging biodegradable plastics.

[0006] (1) Add 4-hydroxybenzamide and triethylamine to dichloromethane, add acryloyl chloride dropwise in an ice-water bath, filter after reaction, evaporate the filtrate by rotary evaporation, and separate by column chromatography to obtain 4-acrylate benzamide.

[0007] (2) Microcrystalline cellulose was added to an ethanol aqueous solution and dispersed by ultrasonication. Then, 4-acrylate benzamide was added, stirred, and an initiator was added under a nitrogen atmosphere to carry out the grafting reaction. After filtration, the mixture was washed with water and ethanol and dried to obtain modified cellulose.

[0008] (3) Polyethylene terephthalate, nylon resin, modified cellulose and antioxidant are added to a mixer and mixed evenly. Then, the mixture is melt-extruded in a screw extruder, pelletized, and injection molded to obtain an anti-aging biodegradable plastic.

[0009] Furthermore, in (1), the amount of 4-hydroxybenzamide is 100 parts by weight, triethylamine is 74-88 parts by weight, and acryloyl chloride is 66-72 parts by weight.

[0010] Furthermore, in (1), the reaction temperature is 20-30℃ and the reaction time is 4-7h.

[0011] Furthermore, in (2), the volume fraction of the ethanol aqueous solution is 10-20%.

[0012] Furthermore, in (2), the reaction temperature is 60-80℃ and the reaction time is 5-8h.

[0013] Furthermore, in (2), the amount of microcrystalline cellulose is 100 parts by weight, 4-acrylate benzamide is 5-20 parts by weight, and the initiator is 0.06-0.22 parts by weight.

[0014] Furthermore, in (2), the initiator is ammonium persulfate or potassium persulfate.

[0015] Furthermore, (3) the amount of polyethylene terephthalate is 100 parts by weight, nylon resin is 50-100 parts by weight, modified cellulose is 20-60 parts by weight, and antioxidant is 0.15-0.3 parts by weight.

[0016] Furthermore, the antioxidants in (3) include hindered phenolic antioxidants and phosphate antioxidants.

[0017] Furthermore, in (3), the temperature of the screw extruder is 190-265℃ and the screw speed is 200-300r / min.

[0018] Furthermore, in (3), the temperature of the injection molding machine is 260-275℃.

[0019] The beneficial technical effects of this invention are as follows: 4-acrylate benzamide is used to graft polymerize microcrystalline cellulose to obtain modified cellulose, which is then blended with polyethylene terephthalate, nylon resin, etc., to obtain anti-aging and biodegradable plastic.

[0020] This invention grafts polymer molecular chains containing benzoate groups and amide bonds onto cellulose molecular chains. The benzoate groups of the polymer molecular chains are structurally similar to those of polyethylene terephthalate, while the amide bonds interact with the amide bonds of nylon resin through hydrogen bonding. This improves the compatibility between cellulose and PET and nylon resin. The microcrystalline cellulose is uniformly dispersed in the composite plastic matrix, maintaining good tensile and flexural strength.

[0021] This invention introduces modified cellulose into PET / PA plastics. Cellulose has better biodegradability, which is beneficial to improving the biodegradability rate and degradability of plastics.

[0022] This invention uses PET and PA, which have excellent heat resistance, as the plastic matrix. They have good high-temperature processing performance and excellent heat and aging resistance. Detailed Implementation

[0023] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to specific examples. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0024] Example 1

[0025] (1) Add 30g of 4-hydroxybenzamide and 26.4g of triethylamine to 400mL of dichloromethane, and add 19.8g of acryloyl chloride dropwise in an ice-water bath. Stir the reaction at 20℃ for 7h, filter, rotary evaporate the filtrate, and separate by column chromatography. The eluent is ethyl acetate-petroleum ether solution, to obtain 4-acrylate benzamide. The reaction formula is:

[0026] .

[0027] (2) 500g of microcrystalline cellulose (CAS No. 9004-34-6, Guangzhou Huayu Biotechnology) was added to 6L of 10% ethanol aqueous solution and ultrasonically dispersed for 40min. Then 25g of 4-acrylate benzamide was added, and after stirring, 0.3g of potassium persulfate was added in a nitrogen atmosphere. The mixture was heated to 70℃ and refluxed for 5h. After filtration, the mixture was washed with water and ethanol and dried to obtain modified cellulose.

[0028] (3) 1 kg of polyethylene terephthalate (PET powder, 99% content, Hubei Maolin New Materials, the same below), 1 kg of nylon resin (model PA6 BKV15H2, Guangzhou Jinfeng Plastic Raw Material), 200 g of modified cellulose, and 2 g of antioxidant 1010 were added to a mixer and mixed evenly. Then, the mixture was melt-extruded in a screw extruder at temperatures of 190℃, 230℃, 255℃, 265℃, and 265℃, with a screw speed of 200 r / min. The mixture was then pelletized and injection molded at temperatures of 260℃, 275℃, and 270℃ to obtain an anti-aging biodegradable plastic.

[0029] Example 2

[0030] (1) Add 30g of 4-hydroxybenzamide and 22.2g of triethylamine to 400mL of dichloromethane, add 21.6g of acryloyl chloride dropwise in an ice-water bath, stir and react at 30℃ for 4h, filter, evaporate the filtrate by rotary evaporation, separate by column chromatography, and eluent is ethyl acetate-petroleum ether solution to obtain 4-acrylate benzamide.

[0031] (2) Add 500g of microcrystalline cellulose to 7L of 10% ethanol aqueous solution, sonicate for 40min, then add 50g of 4-acrylate benzamide, stir, add 0.52g of ammonium persulfate in a nitrogen atmosphere, heat to 80℃, reflux for 5h, filter, wash with water and ethanol, and dry to obtain modified cellulose.

[0032] (3) Add 1 kg of polyethylene terephthalate, 0.8 kg of nylon resin, 300 g of modified cellulose and 3 g of antioxidant 168 to a mixer and mix well. Then melt extrude in a screw extruder with temperatures of 190℃, 230℃, 255℃, 265℃ and 265℃ in each section and screw speed of 300 r / min. Pelletize and injection mold in an injection molding machine with temperatures of 260℃, 275℃ and 270℃ in each section to obtain anti-aging biodegradable plastic.

[0033] Example 3

[0034] (1) 4-acrylate benzamide was prepared according to the method of Example 1.

[0035] (2) Add 500g of microcrystalline cellulose to 8L of 20% ethanol aqueous solution, ultrasonically disperse for 60min, then add 75g of 4-acrylate benzamide, stir, add 0.8g of potassium persulfate in a nitrogen atmosphere, heat to 60℃, react for 8h, filter, wash with water and ethanol, and dry to obtain modified cellulose.

[0036] (3) Add 1 kg of polyethylene terephthalate, 0.65 kg of nylon resin, 450 g of modified cellulose and 3 g of antioxidant 1010 to a mixer and mix well. Then melt extrude in a screw extruder with temperatures of 190℃, 230℃, 255℃, 265℃ and 265℃ in each section and screw speed of 300 r / min. Pelletize and injection mold in an injection molding machine with temperatures of 260℃, 275℃ and 270℃ in each section to obtain anti-aging biodegradable plastic.

[0037] Example 4

[0038] (1) 4-acrylate benzamide was prepared according to the method of Example 1.

[0039] (2) Add 500g of microcrystalline cellulose to 8L of 20% ethanol aqueous solution, sonicate for 40min, then add 100g of 4-acrylate benzamide, stir, add 1.1g of potassium persulfate in a nitrogen atmosphere, heat to 70℃, reflux for 8h, filter, wash with water and ethanol, and dry to obtain modified cellulose.

[0040] (3) Add 1 kg of polyethylene terephthalate, 0.5 kg of nylon resin, 600 g of modified cellulose and 3 g of antioxidant 1010 to a mixer and mix well. Then melt extrude in a screw extruder with temperatures of 190℃, 230℃, 255℃, 265℃ and 265℃ in each section and screw speed of 300 r / min. Pelletize and injection mold in an injection molding machine with temperatures of 260℃, 275℃ and 270℃ in each section to obtain anti-aging biodegradable plastic.

[0041] Comparative Example 1

[0042] (1) Add 1 kg of polyethylene terephthalate, 1 kg of nylon resin and 2 g of antioxidant 1010 to a mixer and mix well. Then melt extrude in a screw extruder with temperatures of 190℃, 230℃, 255℃, 265℃ and 265℃ in each section and screw speed of 200 r / min. Pelletize and injection mold in an injection molding machine with temperatures of 260℃, 275℃ and 270℃ in each section to obtain anti-aging biodegradable plastic.

[0043] Comparative Example 2

[0044] (1) Add 1 kg of polyethylene terephthalate, 1 kg of nylon resin, 200 g of microcrystalline cellulose and 2 g of antioxidant 1010 to a mixer and mix well. Then melt extrude in a screw extruder with temperatures of 190℃, 230℃, 255℃, 265℃ and 265℃ in each section and screw speed of 200 r / min. Pelletize and injection mold in an injection molding machine with temperatures of 260℃, 275℃ and 270℃ in each section to obtain anti-aging biodegradable plastic.

[0045] Comparative Example 3

[0046] (1) Add 500g of microcrystalline cellulose to 6L of 10% ethanol aqueous solution, disperse ultrasonically for 40min, then add 25g of phenyl acrylate (CAS No. 937-41-7), stir, add 0.3g of potassium persulfate in a nitrogen atmosphere, heat to 70℃, reflux for 5h, filter, wash with water and ethanol, and dry to obtain modified cellulose.

[0047] (2) Add 1 kg of polyethylene terephthalate, 1 kg of nylon resin, 200 g of modified cellulose and 2 g of antioxidant 1010 to a mixer and mix well. Then melt extrude in a screw extruder with temperatures of 190℃, 230℃, 255℃, 265℃ and 265℃ in each section and screw speed of 200 r / min. Pelletize and injection mold in an injection molding machine with temperatures of 260℃, 275℃ and 270℃ in each section to obtain anti-aging biodegradable plastic.

[0048] Comparative Example 4

[0049] (1) Add 500g of microcrystalline cellulose to 6L of 10% ethanol aqueous solution, ultrasonically disperse for 40min, then add 25g of acrylamide, stir, add 0.3g of potassium persulfate in a nitrogen atmosphere, heat to 70℃, reflux for 5h, filter, wash with water and ethanol, and dry to obtain modified cellulose.

[0050] (2) Add 1 kg of polyethylene terephthalate, 1 kg of nylon resin, 200 g of modified cellulose and 2 g of antioxidant 1010 to a mixer and mix well. Then melt extrude in a screw extruder with temperatures of 190℃, 230℃, 255℃, 265℃ and 265℃ in each section and screw speed of 200 r / min. Pelletize and injection mold in an injection molding machine with temperatures of 260℃, 275℃ and 270℃ in each section to obtain anti-aging biodegradable plastic.

[0051] The tensile properties of the plastic were tested according to standard GB / T 1040.1-2018. The flexural properties were tested according to standard GB / T 9341-2008. The standard biodegradability was tested according to GB / T 19277.1-2011, and the composting degradation time was 90 days.

[0052] Table 1 Properties of Plastics

[0053]

[0054] The biodegradability of the PET / PA composite plastic in Comparative Example 1 was only 26.8%, indicating poor biodegradability. Comparative Example 2, with the addition of microcrystalline cellulose, achieved a biodegradability of 31.7%, but its tensile and flexural strengths decreased significantly. This was mainly due to the poor compatibility of microcrystalline cellulose with PET (ethylene terephthalate) and PA (nylon resin), resulting in poor dispersion in the composite plastic and severely impacting its mechanical properties.

[0055] Example 1 utilizes the graft polymerization of microcrystalline cellulose with 4-acrylate benzamide. This grafts polymer chains containing benzoate groups and amide bonds onto the cellulose molecular chains. The benzoate groups in the polymer chains are structurally similar to those of polyethylene terephthalate. Simultaneously, the amide bonds interact with the amide bonds of the nylon resin through hydrogen bonding, thereby improving the compatibility between cellulose and PET / nylon resin. The microcrystalline cellulose is uniformly dispersed in the composite plastic matrix without adversely affecting the mechanical properties of the plastic, maintaining good tensile and flexural strength. Examples 2-4, by adjusting different proportions of PET, nylon resin, and modified cellulose, demonstrate composite plastics that possess both good mechanical strength and biodegradability.

[0056] Comparative Example 3 uses phenyl acrylate to graft polymerize microcrystalline cellulose. The resulting modified cellulose does not contain amide bonds and has poor compatibility with nylon resin. The tensile strength and flexural strength of the composite plastic are lower than those of Example 1.

[0057] Comparative Example 4 uses acrylamide to graft polymerize microcrystalline cellulose. The resulting modified cellulose does not contain benzoic acid ester structures and has poor compatibility with PET. The tensile strength and flexural strength of the composite plastic are lower than those of Example 1.

[0058] Furthermore, it should be understood that although this specification describes embodiments, not every embodiment contains only one independent technical solution. This narrative style is merely for clarity. Those skilled in the art should consider the specification as a whole, and the technical solutions in each embodiment can also be appropriately combined to form other embodiments that can be understood by those skilled in the art.

Claims

1. An anti-aging degradable plastic, characterized in that, The anti-aging degradable plastic comprises 100 parts by weight of polyethylene terephthalate, 50-100 parts by weight of nylon resin, 20-60 parts by weight of modified cellulose, and 0.15-0.3 parts by weight of antioxidant. The modified cellulose is prepared by the following method: adding microcrystalline cellulose into an ethanol aqueous solution, dispersing by ultrasonic, then adding 4-acrylate benzamide, stirring, adding initiator in nitrogen atmosphere, carrying out grafting reaction, filtering, washing, drying, and obtaining modified cellulose.

2. The anti-aging degradable plastic according to claim 1, wherein, The antioxidant comprises hindered phenol antioxidant and phosphate antioxidant.

3. The anti-aging degradable plastic according to claim 1, wherein, The volume fraction of the ethanol aqueous solution is 10-20%.

4. The anti-aging degradable plastic according to claim 1, wherein, The reaction temperature is 60-80℃, and the reaction time is 5-8h.

5. The anti-aging degradable plastic according to claim 1, wherein, The amount of the microcrystalline cellulose is 100 parts by weight, the amount of 4-acrylate benzamide is 5-20 parts by weight, and the amount of initiator is 0.06-0.22 parts by weight.

6. The anti-aging degradable plastic according to claim 1, wherein, The initiator is ammonium persulfate or potassium persulfate.

7. The anti-aging degradable plastic according to claim 5, wherein, The preparation method of the 4-acrylate benzamide comprises: adding 100 parts by weight of 4-hydroxybenzamide and 74-88 parts by weight of triethylamine into dichloromethane, adding 66-72 parts by weight of acryloyl chloride dropwise in ice water bath, then reacting at 20-30℃ for 4-7h, filtering, rotary evaporation of the filtrate, column chromatography separation, and obtaining 4-acrylate benzamide.

8. A process for the preparation of an anti-aging degradable plastic as claimed in any one of claims 1 to 6, characterized in that, The preparation method comprises: adding polyethylene terephthalate, nylon resin, and modified cellulose into a mixer, mixing uniformly, then melt extruding in a screw extruder, pelletizing, injection molding in an injection molding machine, and obtaining anti-aging degradable plastic.

9. The method for preparing the anti-aging biodegradable plastic according to claim 8, characterized in that, The temperature of the screw extruder is 190-265℃, and the screw rotation speed is 200-300r / min.

10. The method for preparing the anti-aging biodegradable plastic according to claim 8, characterized in that, The temperature of the injection molding machine is 260-275℃.

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