【作者】 程丝；

【导师】 闻荻江；

【作者基本信息】 苏州大学 ， 材料学， 2005， 硕士

【摘要】 在CB 填充聚合物体系中,不相容的两种聚合物共混代替单—聚合物基体是一种切实可行方法降低炭黑含量,降低电阻率。由于共混相的不同性质,多相结构可提供填料不均匀分布机会,CB 在多相体系中某—区域聚集形成导电网络,有利于提高基体导电性,同时降低炭黑粒子浓度及渗流阀值。本文研究不相容两相HIPS 和EVA 及CB形成的复合材料电性能和PTC 效应,分析半结晶聚合物EVA 对HIPS/EVA/CB 复合体系电性能及PTC 效应的影响,同时采用扫描电镜、X-射线衍射、DSC 等测试手段,分析两相不相容体系的结构、形态,并对结构与性能间关系进行探讨。研究结果如下: 1、非晶HIPS/CB 体系的PTC 强度较弱,其PTC 转变温度与HIPS 的玻璃化转变温度较为接近,同时体积膨胀-电阻率曲线与PTC 曲线较为相似,可认为其PTC 效应与体积膨胀间有一定的关系,但不足以单独解释PTC 现象。2、HIPS/EVA/CB 复合材料的渗流值较HIPS/CB 复合材料得到降低, PTC 强度提高,并且导电复合材料的力学性能得到改善,证实两相不相容聚合物体系能有效提高材料的电性能及PTC 强度。3、扫描电镜,X-射线衍射,DSC 的研究表明, EVA 含量不同,HIPS 和EVA 间两相结构及晶体结构发生变化。随着EVA 含量的增加,HIPS 和EVA 两不相容相间的界面由无明显界面的共连续结构转变成共连续内嵌网络结构,HIPS 相由连续相转变成椭圆形分散相,EVA 由分散相转变成网络状连续相,当EVA 含量增至70phr 后,网络状结构消失。更多还原

【Abstract】 It’s a feasible method to decrease the content of carbon black and the volume electrical resistively with the two immiscible polymer instant of one polymer for the carbon black/polymer composites material. The amorphous HIPS/CB composite materials were prepared by blend, and the PTC effect were studied .and the same ,in order to improve the composite materials’electricity performance and the mechanic performance ,the EVA as semi-crystalline polymer were imported to the composite material. The SEM、X-ray diffraction and the DSC were applied to analyzed the relation of the structure and performance of the two-phase immiscible blends. the result showed: 1、the PTC intension of HIPS/CB is low, and the PTC transform temperature is closed to the glass transform temperature. The composite material’s volume expansion is feebleness, so its volume expansion is not enough to explain the PTC behavior. 2、The percolation value of the HIPS/EVA/CB composite material decreased compared to the HIPS/CB composite material and the PTC intension increased. 3、.The SEM、X-ray diffraction and the DSC showed that the two phase structure and crystal structure changed with the content of EVA.更多还原