硅烷偶联剂对SSBR/SiO_2混炼胶体系动态流变行为的影响

研究了高填充白炭黑(SiO2)补强溶液聚合丁苯橡胶(SSBR)混炼胶体系的动态流变特性,分别考察了在2个混炼温度(120℃、160℃)下添加3种不同偶联剂(TESPT、TESPD、NXT)对其体系中SiO2粒子表面改性的效果.结果表明,在较低混炼温度下添加偶联剂,不利于SiO2粒子表面改性.在较高混炼温度下,偶联剂TESPT、PESPD、NXT均对SiO2粒子表面有改性效果,但同时引起混炼胶不同程度的焦烧,其中以TESPT最明显.随SiO2粒子表面改性程度的提高,出现“Payne效应”的临界应变(γc)值以及低频率(ω)区域lgG′-lgω曲线的斜率值均增大,反映出偶联剂对SiO2与SSBR相互作用的促进以及SiO2粒子分散的改善.

EFFECT OF SILANE COUPLING AGENTS ON DYNAMIC RHEOLOGICAL PROPERTIES FOR UNVULCANIZED SSBR/SILICA COMPOUNDS

Effects of silane coupling agent on the dynamic properties for unvulcanized solution-polymerized styrene butadiene rubber(SSBR)/silica(SiO_2)compounds were investigated on an advanced rheometric expansion system(ARES).It is found that the molecular structure of silane coupling agent significantly influences the dynamic storage modulus(G')in the temperature range from 100℃ to 180℃ and also the strain(γ)and frequency(ω)dependence of G' at 100℃.The highest G' appears for the compound containing bis-(3-triethoxysilylpropyl)-tetraslufide(TESPT),and the lowest for the compound containing 3-octanoylthio-1-propyltriethoxysilane(NXT),indicating different reaction degrees of silane with SiO_2 and SSBR during mixing at 160℃.The molecular structure of silane coupling agents also influences the γ and ω dependence of G' at 100℃.The critical strains(γ_c)for the onset of nonlinear viscoelasticity are 1.00%,0.36% and 0.57%,and the slopes of plotting lgG' versus lgω in the low ω_s range(terminal range)are 0.14,0.17 and 0.20,for the compounds containing TESPT,TESPD and NXT,respectively.It is suggested that the increase of both γ_c value and the slopes of those plots are responsible for surface-modification of SiO_2 particles and enhancement of interaction between the particle and SSBR.