Study On The Mechanical And Tribological Properties Of Polydicyclopentadiene Composites

PDCPD is a kind of excellent thermosetting plastic with combination properties, which is formed by reaction injection molding (RIM) systems and is a new polymer through ring opening metathesis polymerization (ROMP) of dicyclopentadiene (DCPD). PDCPD is widely used as engineering plastic in various areas because of its high impact resistance and high chemical corrosion resistance. However, PDCPD can not meet the need of wear resistant. It is so exciting that many properties of polymers, such as strength, hardness, toughness and wear resistance, etc., can be tailored by filling common inorganic fillers or polymer micropowder. At present, the reports about the tribology of PDCPD are rare.In this article, the surface of expanded graphite was treated with vinyltrimethoxysilane (DB-171), and 5-norbornene-2-carboxylic acid was successfully grafted on the surface of the nano-silica via toluene diisocyanate. Treated expanded graphite (TEG) and functionalized nano-silica were gained. The WCl₆-AlEt₂Cl catalytic system was employed to prepare TEG/PDCPD composites and functionalized nano-silica/PDCPD composites with different filler contents. Furthermore, polyethylene wax (PEW) was also used to prepare PEW/PCDPD composites. Mechanical properties were measured by electronic universal material tester and impact tester; PDCPD composites were tested on the MM-200 wear tester and atmosphere high temperature wear tester (QG-700). The wear properties of PDCPD composites were discussed mainly. Finally, the wear mechanisms of the PDCPD composites under different filler contents were also discussed according to the scanning electron microscopic examination of the worn surface of specimen.The results show that PEW and TEG have better effect of enhancement and toughening on PDCPD. When the PEW content is 3wt%, PDCPD composites are equiped with good flexural and tensile properties, while PDCPD composites with 1wt% PEW content have better impact strength. The mechanical properties of TEG/PDCPD composites with 0.5wt% TEG content are improved. Functionalized nano-silica leads to the mechanical properties of PDCPD materials decline with high content of functionalized nano-silica. For wear resistance, polyethylene wax, TEG and functionalized nano-silica are able to improve the antiwear properties of PDCPD to a certain extent. The abrasion mechanisms are mainly abrasive wear and fatigue wear. It is stated that the agglomeration of fillers is one of the important reasons leading the antiwear and mechanical properties of PDCPD composites to becoming bad.