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

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...

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