硅烷交联聚乙烯的研究

在双螺杆挤出机上进行了硅烷交联聚乙烯的研究，探讨了过氧化二异丙苯(DCP)、乙烯基三乙氧基硅烷(VTES)、二月桂酸二丁基锡(DBTDL)、水温以及聚乙烯种类对交联度的影响规律。发现交联度随DCP和VTES的用量增加而增大，当DCP和VTES的用量增加到一定程度时，交联度的增加程度已不明显；DBTDL和水温仅影响达到最大交联度的时间；在低密度聚乙烯(LDPE)、高密度聚乙烯(HDPE)、线形低密度聚乙烯(LLDPE)3种不同密度聚乙烯制得的交联料中，交联度由大到小的次序为LDPE＞LLDPE＞HDPE；采用HDPE／LLDPE为80／20的共混料可以得到交联度高达77％又综合性能优异的硅烷交联聚乙烯。

Study on Factors Influencing Gel Content of Polyethylene Crosslinked with Silane

Gel content is the most important property of polyethylene cross linked with silane (PEX). It is influenced by many factors in the reactive extrusion. In this paper, initiator (DCP), monomer (VTES), catalyst (DBTDL), water temperature and types of polyethylene, were the factors studied in the two screw extruder. We find gel content of PEX rises with the increasing of DCP or VTES. But the gel content can be stabilized gradually to 82% when the DCP increases to 0.12g and to 63% when the VTES increases to 2g. DBTDL and water temperature only influence the time to the maximum gel content; Comparing the three PEXs corresponding respectively to three different density polyethylenes LDPE, LLDPE, HDPE, we find that gel content is highest for LLDPE, lowest for HDPE, and intermediate for LLDPE. The PEX of 77% gel content can be made by blending of HDPE and LLDPE (80/20), which has excellent synthetic properties and has been used to produce the aluminum plastics compound pipe already.