原材料对铁路扣件绝缘轨距块低温性能的影响研究

摘要

哈齐高速铁路穿越高寒地区，铁路扣件保持轨距的能力对于运营安全和运营成本非常重要。铁路扣件绝缘轨距块以玻璃纤维(33%含量)增强聚酰胺66体系( PA66-GF33体系)作为原材料，在原材料中添加增韧剂来改善绝缘轨距块低温下的力学性能。本文研究增韧剂(马来酸酐接枝三元乙丙橡胶)含量变化对 PA66-GF33体系在常温下力学性能的影响，及其在－30℃和－50℃环境下缺口冲击强度的变化。研究结果表明：原材料中增韧剂含量由3%增加到12%时，缺口冲击强度增大，拉伸强度、弯曲强度和熔融指数降低，扫描电镜分析显示缺口冲击试验的样条断面由脆性断裂逐渐表现为韧性断裂；当增韧剂含量为6%时，PA66-GF33体系同时具有较好的低温韧性和优良的加工性能，选择增韧剂含量为6%的 PA66-GF33体系作为绝缘轨距块原材料，采用注塑工艺制备的绝缘轨距块剖面无内部空隙，并且在－45℃环境下冲击强度试验合格。%Harbin-Qiqihar high speed railway crosses through the frigid area and the track gauge of railway fasteners is important to railway operation safety and cost. T he insulation gauge block material of railway fasteners is glass fiber reinforced polyamide 66 ( Glassfiber content:33%) and addition of toughening agent in the raw material would improve the mechanical properties of insulation gauge block in low-temperature. T his paper studied the influence of toughening agent ( EPDM-g-MAH,maleic anhydride grafted Ethylene-Propylene-Diene Monomer) content on mechanical properties of PA66-GF33 under normal temperature and changes of notched impact strength under-30 ~ -50 ℃ condition. T he results showed that notched impact strength increases and the tensile strength,bending strength and melt index decreases when the EPDM-g-M AH content is from 3% to 12%,the scanning electron microscope ( SEM ) observation indicates that sample piece cross section is from brittle fracture to ductile fracture gradually in notch impact test,PA66-GF33 exhibits good low temperature toughness and excellent processing performance with 6% EPDM-g-M AH content,PA66-GF33 as raw materials of insulation gauge block with 6%EPDM-g-M AH content,insulation gauge block section of which has no internal voids by injection molding processing,is qualified by impact strength test under -45 ℃ environment.