硅烷法聚乙烯交联技术的最新进展

比较了各种聚乙烯交联技术，讨论了硅烷法聚乙烯交联技术的原理，类型，交联和加工特点及其在电缆和管材等方面的应用，详细提供了可交联硅烷乙烯共聚物的最新进展。     

A DYNAMIC MECHANICAL ANALYSIS STUDY OF THE TRANSITION BEHAVIOUR OF I-PP/EPDM BLENDS

The transition behaviour of the blends of isotactic polypropylene (i-PP) with ethylene-propylene terpolymer (EPDM) containing 42 wt% propylene was investigated by dynamic mechanical analysis technique (DMA). Owing to its high propylene content, EPDM is compatible with i-PP to some degree. The interaction between the two components was strengthened. As expected, for partially compatible system the glass transition temperature of i-PP in the blends shifted to lower temperature. It was found that there existed two transitions, αEPDM and βEPDM, for the EPDM used in this work. The former was considered to be the glass transition of the random chain segments of EPDM, while the latter the local motion of the long ethylene sequences in EPDM. The unusual transition behaviour of αEPDM in the blends was explained in terms of the greater thermal expansion of EPDM and the compatibility of the two components. On the other hand, the βEPDM changed with the composition of the blends in a regular manner.     

纳米-CaCO3/OMMT/HDPE三元复合塑料的制备和性能

三元复合塑料;纳米碳酸钙;有机蒙脱土;高密度聚乙烯     

改性纳米CaCO3/PE-g-MAH/HDPE复合塑料拉伸性能研究

采用硬脂酸(SA)对纳米进行表面活化,考察了改性纳米CaCO3、马来酸酐接枝聚乙烯(PE-g-MAH)分别或共同添加到高密度聚乙烯(HDPE)中形成的复合塑料的拉伸性能.结果表明:用质量分数为7%硬脂酸改性的纳米CaCO3,能较好地促使无机粒子的分散和与HDPE的结合,提高复合塑料的拉伸性能.PE-g-MAH的进一步嫁接作用,可延长硬脂酸分子链,加强硬脂酸和基体树脂之间的缠结作用,从而显著提高了复合塑料的拉伸强度.     

STRUCTURE AND THERMAL MECHANICAL PROPERTIES OF ORIENTED POLYIMIDE (PEI-E)

The strain induced crystallization behaviour in polyimide from 1,4-bis (3', 4'- dicarboxyphenoxy)benzene and 4,4'-oxydianiline (PEI-E)has been investigated by WAXD, DSC and FTIR. The results obtained show that crystallization in PEI-E did take place just after tensile yielding. Meanwhile, the effect of strain induced crystallization on the thermomechanical properties was studied by DMA and TMA, the results of which indicate that the crystallization and hot stretching have a certain influence on the dynamic mechanical properties, such as weakening the βrelaxation and decreasing the glass transition temperature. The TMA results confirm the shifting of glass transition temperature to lower temperature region after hot stretching. This phenomenon could be well explained by the effect of residual stress according to Eyring's theory.