摘要
采用熔融挤出法对低密度聚乙烯（ＰＥ）进行硅烷接枝，然后在催化剂二月桂酸二丁基锡（ＤＢＴＤＬ）存在下进行水解交联，对接枝产物的熔体流动速率（ＭＦＲ）和交联样品的凝胶率的影响因素进行了系统的研究。接枝单体为乙烯基三乙氧基硅烷（ＶＴＥＳ），主要引发剂为过氧化二异丙苯（ＤＣＰ）。改变ＶＴＥＳ用量、引发剂种类与用量、ＰＥ种类、接枝反应条件（温度、转速、加料速度等）、加入添加剂等，研究它们对ＭＦＲ和凝胶率的影响。结果发现，在较低用量时，ＶＴＥＳ浓度增加能够提高凝胶率和ＭＦＲ，但超过２％（质量）后凝胶率基本不再随硅烷用量增加而上升，而ＭＦＲ仍有明显降低。引发剂ＤＣＰ用量增大有利于接枝；但当用量达０．１５％（质量）后，凝胶率趋于一定值；不同引发剂的接枝效果差异很大。引发剂是造成接枝产物的ＭＦＲ降低的主要原因，当用量到达０．１５％后，凝胶率不再升高，但接枝产物的ＭＦＲ继续大幅度降低。ＰＥ粉料的接枝和交联效果比粒料好，且在一定范围内，ＰＥ的初始ＭＦＲ对凝胶率的影响不很大。反应挤出温度必须高于１８０℃才能较好的接枝和交联，而螺杆转速对凝胶率的影响存在一最佳值。加入含氮、磷、硫的添加剂可改善接枝产物的流动性能，苯胺在不显著降低凝胶?
Vinyltriethoxysilane(VTES) was grafted onto low density polyethylene(PE) using a Haake twin screw extruder. The grafted products were crosslinked in hot water in the presence of dibutyltin dilaurate. The influences of VTES concentration, initiator type and concentration, PE type, additive type and concentration, as well as processing conditions on the melt flow rate( MFR ) of grafted PE and the gel fraction of crosslinked product were investigated. Gel fraction increases with VTES concentration and reaches a constant value at about 2 mass% VTES, while MFR goes through an optimum value with increasing VTES concentration. Gel fraction increases with increasing initiator concentration at first, and then leveled out at higher initiator concentrations, but MFR decreases further at higher initiator concentrations. High gel fraction and MFR were obtained at the same time with powdered PE. Processing conditions also affect the grafting reaction, there exist an optimum extruder screw speed that leads to the highest gel fraction and a minimum reaction temperature for the reaction to complete. Nitrogen, phosphorous, and sulfur containing additives can improve the processability of grafted PE, aniline was found to be able to greatly increase the MFR of grafted of PE without significant decrease of gel fraction.
出处
《高分子材料科学与工程》
EI
CAS
CSCD
北大核心
1999年第4期133-136,140,共5页
Polymer Materials Science & Engineering
基金
国家教委高校博士点基金
上海市青年科技启明星基金
关键词
聚乙烯
硅烷
交联
挤出
熔体流动速率
接枝共聚
polyethylene, silane, crosslinking, reactive extrusion, melt flow rate
