辛烯/十二烯共聚物的合成及其抗剪切性能

采用本体聚合法,以TiCl_4/Al(i-Bu)_3催化共聚1-辛烯/1-十二烯,合成了超高相对分子质量的油溶性聚合物。用~1H NMR和GPC表征共聚物的构成和相对分子质量及其分布。研究了辛烯加入量对共聚物相对分子质量以及抗剪切稳定性的影响,考察了超声剪切对共聚物相对分子质量分布的影响。结果表明,在最佳聚合条件(十二烯用量50 mL、辛烯用量10 mL、TiCl_4用量0.0157 g、A1(i-Bu)_3用量0.2 mL、反应温度0℃,反应时间48 h)下,共聚物的M_w=7.82×10~6,分散度D=1.98;辛烯用量对共聚物的相对分子质量有明显影响,但分散度变化幅度不大(M_w/M_n=1.8～2.5);辛烯用量对提高共聚物的抗剪切性能无明显作用;共聚物被超声剪切后,其相对分子质量分布为双峰分布,不属于拓扑断裂模型。

SYNTHESIS OF DODECENE/OCTENE COPOLYMER AND ITS SHEAR-RESISTANT STABILITY

A kind of oil-soluble copolymer of ultra high relative molecular mass was synthesized with 1-dodecene and 1-octene as monomers by bulk polymerization using TiCl_4/Al(i-Bu)_3 as catalyst.The structure and relative molecular mass of the copolymer were characterized by ~1H NMR and GPC.Influences of 1-dodecene content on the relative molecular mass and shear-resistant property of the copolymer and the ultrasonic shearing on the relative molecular mass distribution of the copolymer were studied.Under the optimum conditions,i.e.,1-dodecene 50 mL,1-octene 10 mL,catalyst 0.015 7 g,co-catalyst 0.2 mL,temperature 0℃and polymerization time 48 h,the weight-average relative molecular mass and dispersity of the polymer were 7.82×10~6 and 1.98,respectively.The dosage of 1-octene could significantly influence the relative molecular mass of the copolymer,but the distribution remained almost unchanged(M_w/M_n=1.8-2.5).1-Dodecene content did not enhance the shear-resistant property of the copolymer.The MWD of the copolymer exhibited bimodality after ultrasonic shearing,not belonging to the topological scission model.