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采用Ziegler-Natta催化剂催化1-丁烯本体聚合,稀土β-成核剂经原位聚合的方法加入到体系,并考察成核剂加入量对产物聚(1-丁烯)的分子量和结晶性能的影响.通过凝胶渗透色谱(GPC)、示差扫描量热仪(DSC)、偏光显微镜(POM)和广角X射线衍射仪(WAXD)对聚合物进行表征分析.实验结果表明,随着稀土β-成核剂加入量的增大,催化剂活性有所下降,聚合物等规度略有提高,而聚合的分子量显著提高,分子量分布变窄;聚合时成核剂的加入提高了聚(1-丁烯)的结晶性能,随着成核剂加入量的增多聚合物晶粒变小且尺寸趋向均一化,聚合物结晶度也得到了提高,当成核剂加入量为30 mg时,聚合物结晶度和熔融焓出现突变现象.此外,稀土β-成核剂的加入会改变熔融前聚(1-丁烯)中晶型Ⅰ’和Ⅲ所占比例从而影响聚合物的熔点,成核剂的存在也改变了晶型II向晶型I的转变速率,缩短了晶型转变周期.
Ziegler-Natta catalyst was used to catalyze the bulk polymerization of 1-butene and the rare earth β-nucleating agent was added to the system by in situ polymerization. The molecular weight and crystallinity of poly (1-butene) The polymer was characterized by gel permeation chromatography (GPC), differential scanning calorimeter (DSC), polarized light microscope (POM) and wide angle X-ray diffractometer (WAXD) .The experimental results show that with the increase of rare earth β - the amount of nucleating agent increases, the activity of the catalyst decreases, the isotacticity of the polymer increases slightly, while the molecular weight of the polymer increases remarkably and the molecular weight distribution becomes narrower; when the nucleating agent is added during polymerization, the poly (1- Butene). With the increase of the amount of nucleating agent, the polymer grains become smaller and the size tends to be uniform, the crystallinity of the polymer is also improved. When the nucleating agent is added in an amount of 30 mg, the polymer crystallizes Degree and enthalpy of fusion .In addition, the addition of rare earth β-nucleating agent will change the proportion of crystal form I ’and III in the poly (1-butene) before melting to affect the melting point of the polymer, Presence also changes the rate of conversion of Form II to Form I, shortening the cycle of the polymorphic transformation .