硅烷偶联剂对SSBR/SiO_2混炼胶体系动态流变行为的影响

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

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.

Effects of silane coupling agent on the dynamic properties for unvulcanized solution-polymerized styrene butadiene rubber （SSBR）/silica （SiO2） 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-propyltfiethoxysilane （NXT）, indicating different reaction degrees of silane with SiO2 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 （yo） 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 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 γc value and the slopes of those plots are responsible for surface-modification of SiO2 particles and enhancement of interaction between the particle and SSBR.