HDPE/石墨复合体系动态粘弹行为与Mooney方程改进

由于小应变条件下,动态流变行为的测定不会对材料本身的结构造成影响或破坏,动态流变研究被认为是表征填充类聚合物体系填料颗粒的分散状态的有效方法[1～3].众所周知,窄分子量分布的均相聚合物体系在低频率(ω)区域的粘弹行为满足线性粘弹关系,而填充类聚合物基复合材料的流变行为表现出特殊的粘弹特征[4～8],即在低ω区域显示出非线性粘弹行为的特殊响应.特别是所谓的"第二平台(second plateau)"现象,被认为与体系形态结构密切相关[9].

DYNAMIC VISCOELASTIC BEHAVIOR OF GRAPHITE FILLED HIGH DENSITY POLYETHYLENE COMPOSITES AND MODIFICATION OF MOONEY EQUATION

A study of viscoelastic properties of graphite(GP) filled high density polyethylene composites was carried out.The Mooney equation was modified to evaluate the formation and development of agglomerate structure for high filled suspension system.The apparent filler concentration(φ) was substituted by the effective volume fraction,φ_(eff).It is believed that in the case of high filler concentrations the viscoelastic properties of the composites are mainly related with φ_(eff).Here,we define φ_(eff)=fφ,in which f(f≥1) is the experiential factor of effective volume,corresponding to the microstructure with different relaxation time in HDPE/GP system.In the low φ region,the viscoelastic properties of the composites can be described by the original Mooney equation,while the viscoelastic properties of the high loading composites can be described by the modified Mooney equation considering the effective filler volume in the case of ω=0.1 rad/s,experientially postulate f=1.55.