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Expanded graphite modified injection molding grade ultra-high molecular weight polyethylene and preparation method thereof

A technology of ultra-high molecular weight and expanded graphite, which is applied in the field of modified ultra-high molecular weight polyethylene, which can solve the problem of large decline in impact strength and wear resistance of ultra-high molecular weight polyethylene composite materials, unfavorable extrusion of composite materials, and expensive LCP and other issues, to achieve the effects of easy injection molding, improved energy transmission, and low cost

Inactive Publication Date: 2014-05-07
HEFEI UNIV OF TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, due to the addition of decahydronaphthalene, low molecular weight polyethylene, amide lubricants, etc., there is still a certain gap in the tensile strength of the composite material compared with pure ultra-high molecular weight polyethylene, and the melt index is low, and the processing flow Poor performance, which is not conducive to the smooth extrusion of composite materials
[0005] Chinese patent CN1191230A discloses a preparation method for extrusion and injection molding grade ultra-high molecular weight polyethylene modified special materials, adding a certain mass percentage of LCP, antioxidants and additives to ultra-high molecular weight polyethylene to produce a product that can be directly extruded and injection molding ultra-high molecular weight polyethylene modified special materials, but LCP is expensive, which limits its market promotion to a certain extent
Moreover, with the increase of the amount of LCP, the impact strength and wear resistance of UHMWPE composites decreased greatly

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0016] Add 90kg ultra-high molecular weight polyethylene (viscosity average molecular weight 2 million), 10kg high-density polyethylene (2208J), 3kg expanded graphite (200 times volume expansion) Mixed at 40 rpm for 10 minutes, then crushed with a crusher, and finally extruded and granulated by a twin-screw extruder to obtain an injection-molded ultra-high molecular weight polyethylene composite material modified by expanded graphite. The temperature of the screw is 160° C., and the rotational speed of the screw is 80 rpm. The melt index of the obtained ultra-high molecular weight polyethylene blended modified product is 1.2g / 10min, the tensile strength is 28MPa, and the Charpy notched impact strength is 83kJ / m 2 , The coefficient of friction is 0.15.

Embodiment 2

[0018] Add 90kg of ultra-high molecular weight polyethylene (viscosity average molecular weight 3 million), 10kg of high-density polyethylene (2208J), and 5kg of expanded graphite (300 times the volume expansion multiple) into the rubber-plastic internal mixer. Mixed at 50 rpm for 10 minutes, then crushed with a crusher, and finally extruded and granulated by a twin-screw extruder to obtain an injection-molding grade ultra-high molecular weight polyethylene composite material modified by expanded graphite. The temperature of the screw is 180° C., and the rotational speed of the screw is 120 rpm. The melt index of the obtained ultra-high molecular weight polyethylene blended modified product is 1.5g / 10min, the tensile strength is 27MPa, and the Charpy notched impact strength is 81kJ / m 2 , The coefficient of friction is 0.12.

Embodiment 3

[0020] Add 80kg of ultra-high molecular weight polyethylene (viscosity average molecular weight 3 million), 20kg of high-density polyethylene (1300J), 3kg of expanded graphite (200 times of volume expansion) Mixed at 60 rpm for 10 minutes, then crushed with a crusher, and finally extruded and granulated by a twin-screw extruder to obtain an injection-molded ultra-high molecular weight polyethylene composite material modified by expanded graphite. The temperature of the screw is 220° C., and the rotational speed of the screw is 200 rpm. The melt index of the obtained ultra-high molecular weight polyethylene blended modified product is 2.2g / 10min, the tensile strength is 28MPa, and the Charpy notched impact strength is 75kJ / m 2 , The coefficient of friction is 0.18.

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Abstract

The invention discloses an expanded graphite modified injection molding grade ultra-high molecular weight polyethylene and a preparation method thereof. The polyethylene comprises ultra-high molecular weight polyethylene, high density polyethylene and expanded graphite with the weight ratio of (60-100):(5-50):(1-10). The preparation method comprises steps of adding the ultra-high molecular weight polyethylene, high density polyethylene and expanded graphite into a rubber and plastic internal mixer for internal mixing, then crushing by a crusher, finally extruding and pelletizing. As the expanded graphite is stripped at high load and high shearing speed, nano dispersing expanded graphite can be obtained and can form a continuous, uniform and stable lubricant membrane with a matrix, so as to play a lubricant role in ultra-high molecular weight polyethylene composite, energy transfer between polyethylene chains can be improved, the ultra-high molecular weight polyethylene chains relatively slide easily, and the fluidity of the ultra-high molecular weight polyethylene is improved. Furthermore, the expanded graphite is beneficial to lowering the friction coefficient and improving the abrasive resistance of the composite.

Description

[0001] technical field [0002] The invention relates to a modified ultra-high molecular weight polyethylene, in particular to an injection-molding-grade ultra-high-molecular-weight polyethylene modified by expanded graphite. Process for the preparation of polyethylene. Background technique [0003] Ultra-high molecular weight polyethylene (UHMW-PE) is a thermoplastic engineering plastic with a linear structure and excellent comprehensive properties. It has excellent impact resistance, wear resistance, chemical corrosion resistance and self-lubricating properties. It has been It is widely used in harsh environments with the above characteristics, such as in textile, mining, chemical industry, machinery, construction, medical treatment, aviation and military industry and other fields. However, the shortcomings of ultra-high molecular weight polyethylene, such as high viscosity, difficult flow and difficult injection molding, cannot be overcome, which limits the application r...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C08L23/06C08K7/24C08K3/04B29C47/92B29C48/92
CPCC08L23/06C08L2207/062C08L2207/068C08K7/24C08K3/04B29C48/04B29C48/40B29C48/92B29C2948/9259B29C2948/92704B29C2948/92885B29C2948/92895
Inventor 徐卫兵肖时玉周正发任凤梅马海红
Owner HEFEI UNIV OF TECH
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