LDPE硅烷接枝及其交联副反应研究

A Study on Silane Graft LDPE and Crosslinking Side Reaction

研究了以DCP(过氧化二异丙苯)为引发剂,在挤出过程中将不饱和硅烷(乙烯基-三甲氧基硅烷)接枝到LDPE分子链上时,挤出温度、DCP用量、硅烷用量等因素对接枝率及交联副反应的影响,采用红外光谱计算接枝率;通过凝胶含量测定对熔融接枝过程中的交联副反应进行跟踪测量,结果表明,在熔融接枝过程中,交联副反应是二种反应的加和,一种是DCP引发LDPE分子间的C—C交联,另一种是接枝后的大分子链上的—Si(OCH_3)_3基团缩水形成Si—O—Si键交联。配方中硅烷用量为1％左右,DCP用量为0.1％,挤出温度为170～200℃时接枝率较高,挤出物外观质量较好。

With DCP (dicumyl peroxide) as initiator, unsaturated silane is grafted onto LDPE large molecular chain in the extrution process,and the effect of extrution temperature and the concentration of DCP and silane on the graft ratio and crosslinking side reaction are stud-ied in the paper. With infrared spectroscopy the graft ratio is calculated ;at the same time by mea-suring gelation of grafted product the crosslinking side reaction was estimated. The results show that in the melt grafting process the gelation is the result of two reactions :one is C-C crosslinking between LDPE molecules,another is Si-O-Si crosslinking between -Si(OCH3)3 groups. When concentrations of LDPE and DCP are 1% and 0.1% and extrution temperature is 170℃-200℃,high graft ratio and good external quality prodact can be achieved.