聚氯乙烯表皮成分对加成型硅橡胶固化的影响

Effect of Polyvinyl Chloride Skin Composition on Vulcanization of Additive Silicone Rubber

采用流变学方法研究了双组分加成型硅橡胶在不同聚氯乙烯(PVC)表皮上的固化动力学,并利用红外光谱、核磁共振波谱、电感耦合等离子体质谱仪等手段分析了PVC表皮成分,以确定导致双组分加成型硅橡胶不固化的具体原因。结果表明,PVC表皮中导致硅橡胶不固化的主要元素为P元素。在固定硅橡胶厚度为1 mm的情况下,当PVC表皮中的P元素质量分数低于3×10^-3%时,浇注在其上的双组分加成型硅橡胶依然能固化;而当PVC表皮中的P元素质量分数超过约2.4×10^-2%时,虽然浇注在其上的双组分加成型硅橡胶的中间层依然能固化,但与PVC表皮接触部分的硅橡胶不固化,且不固化层厚度随P元素质量分数增加而增加。本文还研究了在P元素质量分数低于3×10^-3%的PVC表皮上,降低硅橡胶厚度至微米级时的固化行为,在P元素质量分数低于3×10^-3%的PVC表皮上,当硅橡胶厚度低于2μm时,硅橡胶出现不完全固化现象。双组分加成型硅橡胶在含有P元素的PVC表皮表面的固化行为主要是由硅橡胶样品中铂催化剂总含量及PVC表皮中的P元素含量确定的,同时也会受到双组分加成型硅橡胶反应速率以及铂催化剂、P元素在硅橡胶中的扩散速率的影响。

In this paper,the curing kinetics of two-component addition silicone rubber on different polyvinyl chloride(PVC)skins was studied with rheological method.The components of PVC skins were analyzed to determine the mechanism of uncuring of two-component addition silicone rubber by using Fourier transform infrared spectrometer(FTIR),nuclear magnetic resonance(NMR),and inductively coupled plasma mass spectrometer(ICP-MS).The results show that phosphorus(P)is the main element in the PVC skin that causes the difficulty in curing of silicone rubber.At the fixed silicone rubber thickness of 1 mm,when the content(mass fraction)of P element in the PVC is below 3×10^-3%,the two-component addition silicone rubber casted on the PVC skin can still be solidified completely;when the content of P in the PVC skin exceeds about 2.4×10^-2%,although the intermediate layer of two-component addition silicone rubber can be cured,the layer contacting PVC skins fails to cure,and the thickness of the uncured layer increases with the content of P.Besides,reducing the thickness of silicone rubber to micron on the skin of PVC with P element content less than 3×10^-3%,especially less than 2μm,the silicone rubber can not cure completely.The consequences mentioned above indicate that the curing behavior of two-component addition silicone rubber on the surface of PVC skin containing P element is mainly influenced by the total content of platinum catalyst in silicone rubber and the content of P element in PVC skin,while the reaction rate of two-component addition silicone rubber and diffusion rates of platinum catalyst and P element in the silicone rubber have ffects as well.