亚乙基苊镍催化剂催化乙烯溶液聚合制备超支化聚乙烯

以一种亚乙基苊(α-二亚胺)镍配合物为主催化剂,研究了温度、压力、助催化剂及其用量等对乙烯溶液聚合制备超支化聚乙烯(HBPE)的影响,并对HBPE的结构与性能进行分析。结果表明:随着温度或压力的升高,催化剂活性均呈现先升高后下降的趋势;HBPE的相对分子质量随温度的升高而下降,而支化度与温度呈正比,与压力呈反比;二氯乙基铝、三乙基铝和甲基铝氧烷均可作为该催化剂的助催化剂,使用二氯乙基铝时的催化剂活性最高,所制HBPE的支化度也最高。

Preparation of HBPE via solution polymerization of ethylene catalyzed by acenaphthylene nickel catalyst

Hyperbranched polyethylene(HBPE)was synthesized via solution polymerization of ethylene with an acenaphthylene(α-diimine)based nickel catalyst.The effects of different conditions such as temperature,ethylene pressure,cocatalyst and its amount on polymerization were investigated.The structures of HBPE obtained was characterized.The results show that the polymerization activity of the catalyst increases first and then decreases with the increase of temperature or ethylene pressure.The molecular mass of the polymer is reduced with the increase of temperature,while whose degree of branching is proportional to the temperature and inversely proportional to the pressure.Dichloroethyl aluminum,triethylaluminum and methylaluminoxane can be used as the cocatalyst of this catalytic system,among which,dichloroethyl aluminum performs the highest polymerization activity and branching degree of HBPE produced is the highest.