STUDIES ON MISCIBILITY AND MORPHOLOGICAL FEATURES OF BLENDS OF LC COPOLYESTER AND PET

The morphology of a special blend system composed of liquid crystalline aromatic random copolyester (LCP) and semiflexible polyester PET over the whole composition range has been studied by means of polarized microscope, density measurement, DSC, FTIR and SEM. Based on the microscopic observation, it is found that under suitable mechanical mixing condition, LCP may be rather homogeneously dispersed in the PET matrix, with the middle composition range of the contents of LCP at 30--70 wt % the anisotropic and isotropic phase segregation appears, while with LCP contents over 80 wt% the blends exhibit wholly anisotropie. The DSC thermographs of the melt-pressed and quenched films show single T_(?), T_(cc) and T_m. T_(?) increases with increasing content of LCP and ap, proaches to the T_(?) of pure LCP. The experimental results indicate that the two components of this blend system are miscible, there exist some specific interactions between them.     

刚性链芳香聚酰胺片晶结构

应用透射电子显微术直接观察了刚性链芳香聚酰胺结晶取向膜的结晶形态结构．结果表明了，在聚对苯二甲酰对苯二胺（ＰＰＴＡ）和聚对苯甲酰胺（ＰＢＡ）的结晶取向膜中均存在有片晶结构．片晶的厚度对ＰＰＴＡ为２０ｎｍ；而对ＰＢＡ为４０ｎｍ，其大小恰好分别与该高聚物分子链的相关长度相当．最后提出一伸直链构象的结构模型来描述这类刚性链高聚物形成片晶结构的分子链堆砌排列方式．     

高分子液晶态有序性对基结晶过程的影响

采用退偏振光强度法、SALS和POM测定了高分子液晶态有序微区结构随体系温度变化的规律，并用DSC法研究具有不同有序微区结构尺寸的液晶态的结晶过程。结果发现，高分子液晶态有序性或有序微区结构是随着体系退火温度和时间的变化而变化。同时从相应的不同有序性为起始态进行结晶时，其结晶速率明显不同，并讨论了高分子液晶态的结晶机理。     

珠状热敏电阻的试制

一、緒论热敏电阻是一种用过渡元素(周期表中从钛至銅)的金属氧化物为材料制成的半导体电器元件,它的电导率介乎导体和絕緣体之間;并且是随着温度的升高而急剧減小。通常溫度变化1℃时其电阻改变为原来电阻的2％—6％,比起普通金属导体的溫度系数(如铂的溫度系数为0.42％)約大十倍,所以可以利用它来做为对溫度的敏感元件。不但其电阻对溫度变化极