共查询到16条相似文献,搜索用时 171 毫秒
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高抗冲聚丙烯(hiPP)以其优异的力学性能成为当前聚丙烯行业中的一类代表性产品,具有广阔的应用前景,关于其结构与性能的分析和关联一直都是研究的热点之一。综述了近年来关于高抗冲聚丙烯结构与性能分析的最新进展,一方面从体系相形态入手,分析提高hiPP 抗冲性能的分散相形态及其分布;另一方面从分子链结构出发,将hiPP 中各组分归纳为乙丙橡胶、乙丙短嵌段共聚物、乙丙嵌段共聚物和等规聚丙烯等,并阐述了各自的作用及影响因素。 相似文献
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国外抗冲共聚聚丙烯结构的研究 总被引:2,自引:1,他引:1
利用升温淋洗分级柱、核磁共振波谱仪、差示扫描量热仪、凝胶渗透色谱仪和扫描电子显微镜等研究了国外抗冲共聚聚丙烯(PP)的组成、序列结构、相对分子质量及其分布、热转变、相态结构和宏观性能.结果表明,该抗冲共聚PP由均聚PP、乙丙橡胶和可结晶的乙丙共聚物组成,具有优良的机械性能;均聚PP为抗冲共聚物提供刚性,乙丙橡胶可提高抗冲共聚物的韧性;抗冲共聚物的相对分子质量呈多分散性,其分布较宽;乙丙橡胶的相对分子质量较大,以直径为1~2μm的微粒均匀分布在PP基体中,有利于提高抗冲共聚物的冲击强度;抗冲共聚物的熔点较高,耐热性好. 相似文献
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<正> 聚丙烯的分子量和分子量分布对它的纺丝性能有很大的影响。分子量较大、分子量分布较宽和具有较多高分子量尾端的聚丙烯树脂,纺出的卷绕丝容易形成α-晶型结构,纺丝性能和拉伸性能都较差。用当前的纤维级树脂(粘均分子量在22万左右)进行纺 相似文献
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设计合成了一系列不同相对分子质量和乙烯平均序列长度的乙丙嵌段共聚物(EP),并将其作为聚丙烯(PP)/二元乙丙橡胶(EPR)共混体系的增容剂,考察了EP用量、相对分子质量及乙烯平均序列长度对共混体系性能及分散相形态演变的影响。结果表明,EP增容PP/EPR体系时存在最佳添加量,少量EP的加入可有效提高PP/EPR共混体系的抗冲击性能,并对分散相尺寸及形态起到良好的调控作用;同时,EP的相对分子质量越大对共混体系的冲击性能提高越明显,EP的组成与EPR越接近,对共混体系的增容效果越明显。 相似文献
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Factors influencing the impact toughness of two impact polypropylene copolymers (IPC) with almost the same ethylene content, molecular weight and molecular weight distribution were studied by temperature gradient extraction fractionation (TGEF), scanning electron microscopy (SEM), nuclear magnetic resonance (NMR) and differential scanning calorimetry (DSC). The results indicate that poor interfacial adhesion between the disperse phase and the continuous matrix, larger dimensions and non-uniform distribution of disperse phases are main reasons for the low impact toughness of IPC B that possesses of a low content of ethylene-propylene segmented copolymer with long crystallizable PE and PP sequences as a compatibilizer between the disperse phase and the matrix. 相似文献
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Propylene polymerizations were conducted in slurry phase batch process using different dialkyldimethoxysilanes as an external
donor with magnesium dichloride (MgCl2) supported titanium tetrachloride (TiCl4) catalyst having diisobutylphthalate (DIBP) as an internal donor. The dialkyl group of the external donors like dimethyldimethoxysilane
(DMDMS), diisopropyldimethoxysilane (DIPDMS) and dicyclopentyldimethoxysilane (DCPDMS) were found to influence on the microstructure
and the molecular weight characteristics of synthesized polypropylene in addition to the initial rate of polymerization and
decay index. DCPDMS gave highest productivity and high molecular weight polypropylene with improved kinetics while DMDMS gave
lowest productivity in comparison. The molar equivalent combination of DCPDMS with DIPDMS and DMDMS respectively, resulted
in producing polypropylene with tacticity pattern and molecular weight characteristics in between the individual alkoxysilane
based system indicating the effect of alkyl group on the catalyst performance. 相似文献