共查询到19条相似文献,搜索用时 109 毫秒
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《现代塑料加工应用》2018,(5)
应用TREF-GPC联用技术,直接得到了抗冲聚丙烯(PP)样品的温度、占比含量、相对分子质量及其分布的三维谱图和支化度(CH3/1000C)信息,能够清晰地看到复杂抗冲PP样品具有7种组成成分,分别为小分子的PP和PE(聚乙烯),无规PP,高等规PP,低等规PP,乙丙橡胶,含共聚单体的乙丙共聚物和均聚PE;此外,对比表征了3种抗冲PP样品(HecoA,HecoB,HecoC)的微观结构,结果显示,HecoA样品的小分子聚合物成分、乙丙共聚物成分、PE和PP成分含量均大于HecoB和HecoC的,并找到了HecoA样品在抗冲性能方面优异的原因。 相似文献
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研究了乙丙嵌段共聚聚丙烯(PP-B)管材专用树脂的结构与性能。PP-B具有典型的乙丙嵌段共聚物序列结构,是含有丙烯均聚物(PP-H)、乙丙橡胶(EPR)及可结晶乙丙共聚物的抗冲聚丙烯(PP);其中,均聚物与共聚物比例合理,形成的EPR多、粒径小,对提高冲击强度有利。提高PP-H的质量分数和等规指数,可有效提高PP- B的刚性。PP-B的熔点与PP-H近似;相对分子质量分布较宽,流变性能好;微观与亚微观结构合理,宏观性能优良。 相似文献
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采用核磁共振波谱仪、差示扫描量热仪、原子力显微镜、毛细管流变仪、熔体扭矩流变仪等表征了聚丙烯(PP)管材专用树脂H2483的组成、序列结构、相对分子质量分布、相态结构、流变行为,并测试了力学性能.H2483由均聚PP、乙丙橡胶组成;均聚PP为树脂提供了刚性,橡胶相提供了韧性;H2483的相对分子质量分布较宽,熔点为166.3℃,弯曲强度达到34.7 MPa,适宜挤出大口径管材. 相似文献
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《现代塑料加工应用》2016,(5)
采用分析型升温淋洗仪(A-TREF)研究了抗冲聚丙烯1215C的化学组成分布,利用制备型升温淋洗仪(P-TREF)、核磁共振仪(NMR)、差示扫描量热仪(DSC)、高温凝胶色谱(GPC)等方法研究了抗冲聚丙烯1215C的组分含量、序列结构、相对分子质量、热行为。结果表明:P-TREF所得7个组分中,第1个组分质量分数21.64%,具有典型的乙丙橡胶结构,相对分子质量较高且分布窄。第2~4个组分质量分数共计7.51%,主要为长乙烯链段的乙丙共聚物,含有少量低相对分子质量聚丙烯,相对分子质量较大且分布宽。第5个组分质量分数为4.38%,是91.83%较低相对分子质量聚丙烯和8.17%聚乙烯组成的混合物。第6~7组分为聚丙烯均聚物,质量分数为66.02%,相对分子质量较高且分布窄。 相似文献
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^13C-NMR在抗冲共聚聚丙烯序列结构研究中的应用 总被引:1,自引:0,他引:1
论述了^13C-NMR在抗冲共聚聚丙烯序列结构研究中的进展。介绍了抗冲共聚聚丙烯N脉谱图及谱图归属和单元组的分布、组成及数均序列长度的计算方法。研究结果表明抗冲共聚聚丙烯主要是由乙丙无规共聚物、乙丙可结晶共聚物(富含乙烯或丙烯均可能存在)和聚丙烯均聚物组成。 相似文献
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通过核磁共振波谱仪、凝胶渗透色谱仪、差示扫描量热仪、扫描电子显微镜等对乙烯-1-丁烯共聚物为橡胶相的抗冲共聚聚丙烯的结构进行了分析,并测试了其模塑收缩率及耐应力发白性能。结果表明:乙烯-1-丁烯共聚物可溶物的相对分子质量较低时,所制抗冲共聚聚丙烯在注塑过程中易受到剪切应力作用而沿熔体流动方向形成柱状取向结构,此橡胶相取向结构赋予抗冲共聚聚丙烯低模塑收缩率和良好的耐应力发白性能;乙烯-1-丁烯共聚物可溶物的相对分子质量较高时,所制抗冲共聚聚丙烯在注塑过程中则呈现典型的"海-岛"状橡胶形态,因而表现出较高的模塑收缩率和较差的耐应力发白性能。 相似文献
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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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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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高流动抗冲共聚PP的相态结构 总被引:1,自引:0,他引:1
用扫描电子显微镜和偏光显微镜.对氢调法和降解法生产的高流动抗冲共聚聚丙烯(PP)的微观结构进行了分析.特别对其中橡胶相在PP中的形状、尺寸和分布进行了研究。通过进行刻蚀条件的选择,分析比较不同PP中橡胶相微观结构的差异.找出了2种方法生产PP的最佳刻蚀条件。同时.对庚烷及癸烷的可溶物和不溶物做偏光显微分析。结果表明:降解法生产的PP橡胶相中确实存在少量可结晶的聚乙烯链段;在PP链上存在乙丙橡胶链嵌段。 相似文献
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Ivan Fortelný Danue Michlkov Jaroslava Koplíkov Edita Navrtilov Josef Kov 《大分子材料与工程》1990,179(1):185-201
The dependence of morphological structure and notch impact strength of polypropylene/ethylene-propylene elastomer blends on conditions of mixing was investigated. Two types of polypropylene and two types of ethylene-propylene elastomer having different viscosities were used. At low rates and short times of mixing the samples contain both regions showing fine dispersion and regions showing large elastomeric inclusions surrounded with pure polypropylene. With increasing rate and time of mixing the large inclusions gradually disappear. The conditions of mixing which are necessary for reaching a homogeneous structure of the blends depend on viscosities of the components. The independence of particle size of the rate of mixing in homogeneous samples is discussed on the basis of a dynamic equilibrium between the break up and coalescence of droplets. The notch impact strength of the individual samples of the same blend is determined by the size and number of inhomogeneities (large inclusions) in the given sample. 相似文献
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Chunhui Zhang Yonggang Shangguan Ruifen Chen Yuanzhi Wu Feng Chen Qiang Zheng Guohua Hu 《Polymer》2010,51(21):4969-1792
The morphology of impact polypropylene copolymer (IPC) was studied through scanning electron microscope (SEM) and transmission electron microscope (TEM) observation, and a modified dispersed phase model of IPC with core-shell structure was proposed. Through fractionation of IPC, the glass transitions of the ethylene-propylene random copolymer (EPR) fraction, ethylene-propylene block copolymer (EbP) fraction and propylene homopolymer (iPP) fraction were detected, respectively. Moreover, the glass transitions and crystallization behaviors of EbP/iPP and EPR/EbP fraction blends were systemically investigated and several reasonable chain structures of EbP component were confirmed. The results reveal that the EbP component presents three glass transition peaks, and the glass transition temperature of ethylene-propylene random copolymer in IPC sample is remarkably lower than that of pure EPR fraction due to the existence of special structure of EbP component in IPC. In addition, co-crystallization occurring between the polypropylene chains in EbP fraction and in iPP fraction was found for solution-mixed EbP/iPP blends, and it is believed that there exists a dilute effect of EPR on the crystallization of EbP fraction for the solution-mixed EPR/EbP blends. Accordingly, it can be inferred that EbP fraction has good compatibility with both EPR and iPP fraction, and indeed it confirms that the compatibilization effect of EbP fraction in IPC was good. 相似文献