高速铁路无砟轨道嵌缝用有机硅密封胶的研制

摘要

The silicone sealant with low modulus and high elongation was prepared by α,ω-hydroxy-teminated polydimethylsiloxane as the base polymer combined with the fillers,chain extender,crosslinking agent,coupling agent and catalyst.The formula was that 100 parts basic rubber,90 parts nano-calcium carbonate,4 parts chain extender,8 parts mixed crosslinking agent with the mass ratio of MOS,VOS and POS was 5:2:3.The silicone sealant prepared showed a good performance,tensile strength was 1.5 MPa,elongation at break was 993%,100% constant modulus was 0.27 MPa and the tensile strength disposed by ultraviolet for 1500 h was 1.3 MPa.The performance meets the requirements of Joint material of the high-speed railway ballastless track (Draft).%以α,ω-二羟基聚二甲基硅氧烷为基础聚合物,配合填料、扩链剂、交联剂、偶联剂和催化剂等,制得低模量、高伸长率的室温硫化有机硅密封胶.较佳配方为:复配基胶用量100份,自制扩链剂用量4份,纳米碳酸钙用量90份,复配交联剂(MOS、VOS、POS质量比为5∶2∶3)用量8份.以此配方制得密封胶的拉伸强度为1.5 MPa,拉断伸长率993%,100%模量为0.27 MPa;经紫外光老化处理1 500 h后拉伸强度为1.3 MPa,其性能满足《高速铁路无砟轨道嵌缝材料》(征求意见稿)的要求.