有机蒙脱土对端羧基聚丁二烯凝胶流变行为的影响

在恒定剪切速率下,利用旋转流变仪研究端羧基聚丁二烯/蒙脱土纳米复合凝胶的流变行为,同时利用X-射线衍射(XRD)和透射电镜(TEM)等表征手段研究其微观结构.研究结果表明,该体系在26～116℃的升-降温过程中,观察到不可逆转变和可逆转变两种流变行为,其中不可逆转变流变行为归因于蒙脱土片层的剥离过程,而可逆转变流变行为...

EFFECT OF ORGANOCLAY ON THE RHEOLOGICAL BEHAVIOR OF CARBOXYL-TERMINATED POLYBUTADIENE GELS

The unique rheological behavior of carboxyl-terminated polybutadiene(CTPB)/organoclay nanocomposite gels was studied under steady shear on a HAAKE RheoStress 600 instrument.The microstructure of nanocomposite gels was characterized by X-ray diffraction(XRD) and transmission electron microscopy(TEM).The experimental results show that both irreversible and reversible viscosity transitions were observed in the temperature range from 26℃ to 116℃ in steady shear experiments on as-prepared samples.The irreversible viscosity transition is attributed to the exfoliation of the clay sheets,and the reversible viscosity transition can be understood as a shear-induced orientation-disorientation transition of the clay sheets.Moreover,the in-situ dispersion process of organoclay in CTPB matrix was observed by rheological experiments,and three important factors that significantly affected the rheological behavior of CTPB/organoclay nanocomposite gels in the steady shear measurement were studied:the temperature effect,the shear-induced orientation effect and temperature-sensitive polymer-clay interaction.Finally,a possible mechanism was suggested on the basis of the clay exfoliation and orientation-disorientation transition,and the mechanism was used to explain the effect of organoclay on the rheological behavior of CTPB gels and the relationship between the observed unique rheological behavior and the microstructure of nanocomposite gels.