摘要
采用差示扫描量热和偏光显微镜考察了茂金属催化剂制备PP(mPP)和齐格勒⁃纳塔催化剂制备PP(ZNPP)的熔融结晶行为;采用频率扫描和熔体拉伸的方法,考察了它们的流变学特征。进行釜压发泡实验并对发泡珠粒的熔融结晶、发泡倍率和泡孔结构进行测试表征。结果表明,由于分子量大小及分布的影响,ZNPP具有更高的表观黏度,以及更显著的剪切变稀现象;因为ZNPP分子链缠结更强烈,故在较高温度下熔体强度高于mPP,但在较低温度下二者熔体强度相近。较ZNPP,mPP可以制得倍率相近的釜压发泡PP(EPP)珠粒,但泡孔形态质量有待于进一步提高。
The melting and crystallization behavior of two types of polypropylene,named as mPP and ZNPP,were stud⁃ied by using differential scanning calorimeter(DSC)and polarized microscope(POM),and their rheological characteristics were analyzed through frequency scanning and melt stretching.Autoclave foaming experiments were conducted to investigate the melting crystallization behavior,foaming ratio,and cell structure of the expanded polypropylene(EPP)beads.The results indicated that ZNPP had a higher complex viscosity and more obvious shear thinning,leading to higher molecular weight size and distribution.ZNPP exhibits higher melting strength than mPP at higher temperatures due to more intense molecular chain entanglement.However,its melt strength is similar to that of mPP at lower temperatures.The quality of the cell structure needs to be improved,when mPP is used to produce EPP beads with similar ratios to ZNPP.
作者
沈强锋
吕明福
徐耀辉
SHEN Qiangfeng;LYU Mingfu;XU Yaohui(Sinopec Ningbo New Materials Research Institute Company Limited,Ningbo 315299,China;SINOPEC(Beijing)Research Institute of Chemical Industry Co,Ltd,Beijing 100013,China)
出处
《中国塑料》
CAS
CSCD
北大核心
2024年第7期55-61,共7页
China Plastics
关键词
茂金属聚丙烯
剪切变稀
熔体强度
釜压发泡
泡孔结构
metallocene polypropylene
shear thinning
melt strength
autoclave foaming
cell structure
