用Z-N催化剂分段聚合制备PP/EPR共混物的结构和形态特征

用Ziegler-Natta(Z-N)催化剂MgCl2/TiCl4/BMF-AlEt3(BMF代表内给电子体9,9-二甲氧基甲基芴),采用分段聚合的方法制备了PP/EPR原位共混物,通过改变乙丙共聚的时间调节聚合物中乙烯的含量.使用核磁共振(13C-NMR)、凝胶渗透色谱(GPC)、示差扫描量热分析法(DSC)、动态力学分析(DMA)、扫描电子显微镜(SEM)和偏光显微镜(PLM)等研究了聚合物的结构和形态特征.研究发现,分段聚合制备的PP/EPR共混物是一种包括丙烯均聚物、乙丙无规和嵌段共聚物在内的多组分混合物.动态力学的结果显示混合物中聚丙烯与乙丙无规共聚物的玻璃化转变峰出现了内移现象,说明两者呈现部分相容性.扫描电镜的照片表明了聚丙烯基体与乙丙无规共聚物分散相之间的相界面模糊,两相之间的相容性较好.随着聚合物中乙烯含量的增加,分散相出现明显的塑性变形,同时,聚丙烯的结晶形态也发生明显的变化,球晶的尺寸逐渐变小,同时球晶变得不完善.

THE STRUCTURE AND MORPHOLOGY CHARACTERS OF PP/EPR in situ BLENDS SEQUENTIALLY PREPARED BY ZIEGLER-NATTA CATALYST

PP/EPR in situ blends were prepared by the sequential polymerization technique using a Ziegler-Natta catalyst MgCl_2/TiCl_4/BMF(BMF is 9,9-bis(methoxymethyl)fluorine as an internal donor).The content of ethylene unit in blends was adjusted by modifying the time of ethylene-propylene copolymerization.The structure and morphology characters of the blends obtained were investigated by nuclear magnetic resonance(NMR),gel permeation chromatography(GPC),dynamic mechanical analysis(DMA),differential scanning calorimetry(DSC),scanning electron microscopy(SEM) and polarized light microscopy(PLM).The results suggested that PP/EPR is a complex multiphase mixture including PP,EPR and EP block copolymer.The presence of EP block copolymer greatly improved the compatibility between the PP matrix and the EPR dispersed phase in the multiphase system.The compatibility between the PP matrix and the EPR dispeersed phase in the multiphase system.The change of the ethylene unit content in PP/EPR remarkably influenced the crystalline morphology of PP with increasing the content of ethylene unit in the blend,the PP spherulites became smaller and irregular.