Mechanical And Tribological Properties Of Short Basalt Fiber-reinforced Polyoxymethylene Composites

In recent years,with the increasing awareness of environmental issues,more and more people began to focus on natural fiber reinforced polymer matrix composites.Basalt fiber(BF)originated from volcanic rock shows equivalent tensile strength,higher modulus and better alkaline resistance as compared with the glass fiber.In addition,compared with the carbon fiber,BF has the characteristics of lower cost,higher flame retardance and more excellent thermal insulation.In this paper,short basalt fiber(BF)-reinforced polyoxymethylene(POM)composites were prepared by melt blending and injection molding.The impact of the BF content and length on the mechanical and tribological properties of the composites was studied.The formulations of BF/POM composites have been optimized by an orthogonal experiment.After the optimal combination is confirmed,10wt% PTFE would be added into the optimal combination to improve its tribological properties.The cross section and worn surface morphology of the composites have been observed and analyzed by a scanning electron microscope(SEM).Results are as follows.1)The mechanical and tribological properties of the composites are related to the BF content.After the BF’s addtion,the mechanical properties of the composites could be improved significantly,however,its tribological properties would be worse as compared with that of the pure POM.The tensile strength,notched impact strength,friction coefficient and wear loss of the composites are increased with the increase of BF content.And the flexural strength shows a trend of first decreased then increased and keep stable at last with the increase of BF content.2)The mechanical and tribological properties of the composites related to the BF length.The tensile strength and flexural strength are increased with the increase of BF length.The notched impact strength and friction coefficient shows a trend of first increased then decreased with the increase of BF length,but the wear loss shows a trend of first decreased then increased with the increase of BF length.3)Considering the impact of the BF amount,length and surface treatment methods onthe mechanical and tribological properties of the composites,the formulations of BF/POM composites have been optimized by an orthogonal experiment.The result of the optimal combination for comprehensive properties is fiber length 4mm,fiber addition 20 wt% and treated with KH550.4)After confirming the optimal combination of the composites,10wt% of PTFE had been added into the optimal combination to improve its tribological properties.The friction coefficient and wear loss of the composites are close to pure POM,and the impact strength is close to the optimal combination,but the tensile strength and flexural strength are decreased.