新癸酸钕-三辛基铝-叔丁基氯催化体系合成高顺式聚异戊二烯

Synthesis of high cis-1,4-polyisoprene by neodymium capratetri-n-octyl aluminum-tert-butyl chloride catalyst

以新癸酸钕(简称Nd)-三辛基铝(简称Al)-叔丁基氯(简称Cl)为催化剂合成了聚异戊二烯(IR),考察了催化剂的配制顺序、陈化温度和时间、陈化方式、组分比、聚合温度对聚合活性和IR微观结构的影响,并与传统催化剂Nd-三异丁基铝-倍半乙基氯化铝合成的IR结构与性能进行了比较。结果表明,催化剂采用Nd和Al先混合30 min、再与Cl混合的陈化方式(陈化温度50℃,陈化时间为45 min),在Al/Nd(摩尔比)为25、聚合温度为50℃的条件下可以合成顺式-1,4-结构摩尔分数不小于96%的IR;与传统Nd催化剂相比,Nd-Al-Cl对异戊二烯的聚合活性更高,且IR的顺式-1,4-结构含量更大;由Nd-Al-Cl制得IR生胶的拉伸强度和扯断伸长率均高于传统Nd催化剂制得IR,且存在应变诱导结晶现象,而硫化胶的拉伸强度与天然橡胶相近,其与扯断伸长率均高于传统Nd催化剂制得IR和钛系IR。

Using rare earth catalyst Nd（VA）3（simplified as Nd）-Al（Oct）3（simplified as Al）-（CH3）3CCl（simplified as Cl）,the polyisoprene rubbers（IR） were synthesized.The effects of feeding sequence,aging temperature,aging time,aging mode and component ratio of the catalyst as well as polymerization temperature on activity and microstructure were investigated.Furthermore,the properties of prepared IR was compared with those of IR synthesized by traditional catalyst [Nd（VA）3-Al（i-Bu）3-Al2Et3Cl3].The results showed that the IR with cis-1,4-unit mole fraction of 96% could be synthesized when Nd was mixed with Al for 30 min,and then with Cl at 50 ？栦or 45 min,Al/Nd（mole ratio）was 25,and polymerization temperature was 50 ？殃ompared with traditional Nd catalyst,Nd-Al-Cl catalyst had higher activity and higher cis-1,4-unit content in its polymer product.The tensile strength and elongation at break of Nd-Al-Cl based IR raw rubber were higher than those of traditional Nd based one,and the former had ＂strain induced crystallization＂ trend.The Nd-Al-Cl based IR vulcanizate was close to natural rubber vulcanizate in tensile strength,and better than traditional Nd based IR vulcanizate in both of tensile strength and elongation at break.