【摘 要】
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Polybutene-1 was modified with rare earth β-nucleating agents which were introduced in situ during bulk polymerization of butene-1.The influence of nucleat
【机 构】
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Daqing Petrochemical Research Center,Petrochemical Research Institute of CNPC,Daqing Heilongjiang 16
论文部分内容阅读
Polybutene-1 was modified with rare earth β-nucleating agents which were introduced in situ during bulk polymerization of butene-1.The influence of nucleating agent amount on the molecular weight,melting temperature(Tm),degree of crystallization(xc)behavior of resulting polybutene-1 was investigated in detail by gel permeation chromatography(GPC),differential scanning calorimeter(DSC),polarizing microscopy(POM),and wide angle X-ray diffraction(WAXD).The results show that with the increase of nucleating agent content the isotacticity of polybutene-1 was slightly increased,the number-average molecular weight was obviously improved and the molecular weight distribution was narrowed while the activity of Ziegler-Natta catalyst was somewhat decreased.The addition of rare earth β-nucleating agents changed the crystallization behavior of polymers,the spherulites size of nucleated polybutene-1 dramatically decreased compared with that of pure polybutene-1 and tends to homogenization with the increasing of nucleating agents content,the χc of polybutene-1 is improved,especially when the addition of β-nucleating agents is 300mg,but dropped dramatically after this point.In addition,the rare earth β-nucleating agents not only play a positive role improving Tm by changing the proportion of forms Ⅰ' and Ⅲ,but also speed up the transformation of crystalline form from Ⅱ to Ⅰ,shorten the crystal transformation period.
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