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由中国科学院化学研究所申请的专利(专利号CN1293139,公开日期2005~11—16)“纳米硅橡胶改性超高相对分子质量聚乙烯及其制备方法和用途”,涉及一种硅橡胶改性超高相对分子质量聚乙烯的制备方法及其在耐磨管材中的应用。硅橡胶改性超高相对分子质量聚乙烯配方为:超高相对分子质量聚乙烯80~99,纳米硅橡胶0.1~15,润滑剂0.01~5,加工流变助剂0.01~5,成核剂0.01~5,抗氧剂0.1~0.5。制备步骤是先将超高相对分子质量聚乙烯、成核剂、润滑剂、加工流变助剂和抗氧剂在高速搅拌机内混合搅拌,再加入粒径为20~100nm的纳米硅橡胶继续搅拌,然后将混合均匀的物料加入双螺杆挤出机中进行共混造粒, 相似文献
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将3种不同熔体流动指数(MFI)的聚丙烯(PP)按一定的质量比通过机械混合均匀,在单螺杆挤出机上纺成直径分别为0.20,0.25,0.30 mm的单丝,研究了PP的MFI与其相对分子质量及其分布之间的关系,以及相对分子质量及其分布对PP结晶行为和力学性能的影响。结果表明:混合后的PP熔体MFI介于两种原料的MFI值之间,且PP的相对分子质量及其分布随着MFI值的变化而变化,MFI越高,PP的相对分子质量越低;随着相对分子质量分布变窄,PP的结晶温度和熔融温度降低,结晶度增大,结晶速度加快;3组混合试样分别在MFI每10 min为3.74,4.80,11.21 g时相对分子质量较小,相对分子质量分布最窄,PP单丝的力学性能达到最佳,且直径为0.20 mm时的PP单丝力学性能最好。 相似文献
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田瑶珠;王松;秦军;于杰;罗筑 《中国塑料》2011,25(4):55-58
采用差示扫描量热仪和凝胶渗透色谱仪研究了PP粉粒径大小对其相对分子质量及分布、结晶行为和力学性能的影响。结果表明,粒径大小对PP粉的相对分子质量及分布、结晶温度、结晶速率、成核能力、力学性能等均有明显的影响。随着粒径的减小,PP粉的数均相对分子质量下降,相对分子质量分布变宽,熔体流动速率逐渐增大;结晶温度和结晶起始温度升高,成核能力增加,起始结晶速率增大,晶粒更加细化均匀;但其拉伸强度和缺口冲击强度有不同程度的下降。 相似文献
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1,3—2,4-二亚(对甲基)苄基山梨醇(MDBS)可以改变PP结晶结构,细化晶粒结构尺寸,提高结晶度,加快结晶速度和其它性能。以MDBS为成核剂,使用溶液沉淀法制备MDBS质量分数分别为0.1%、0.3%、0.5%、0.7%、0.9%的粉末聚丙烯样品,采用红外光谱仪、差示扫描量热仪,X-射线衍射仪和偏光显微镜等技术进行结晶性能的研究。结果表明,透明成核剂MDBS是PP的有效α诱导剂,MDBS的加入能诱导大量球晶生成,使结晶峰尖锐,结晶温度区间变窄,提高PP的结晶速率和结晶度,差示扫描量热法测得结晶度提高19%左右。FT-IR,X-ray衍射和DSC等分析结果一致,即在PP中添加0.3%MDBS时,聚丙烯的改性效果最好,PP的结晶度达到最大值。 相似文献
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采用过氧化二异丙苯(DCP)降解PP/POE共混物。熔体流动速率试验结果表明,当DCP含量从0.2‰(质量分数,下同)增加到1‰时,对应的共混物的熔体流动速率从7.0g/10min增加到17.2g/10min,二者基本成线性关系。并且这种增加(相对分子质量的降低)导致其冲击性能从125J/m下降到50J/m;拉伸实验结果表明,共混物相对分子质量的降低对其屈服应力影响不大,这说明相对分子质量的降低主要是引起基体断裂应力的降低,从而导致共混物的冲击强度大大降低;通过扫描电子显微镜观察了不同相对分子质量共混物中橡胶相的分散情况,结果表明,随着DCP含量的增加,共混物中橡胶相的相区尺寸明显增加。因此,共混物冲击强度的降低是基体相对分子质量降低与橡胶相粒径变化共同作用的结果。 相似文献
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在过氧化二异丙苯(DCP)引发下,研究三烯丙基异氰脲酸酯(TAIC)对聚丙烯(PP)的交联程度、熔体强度及其发泡性能的影响。在TAIC加入前后,分别测定PP的抗流淌能力和熔体流动速率及PP发泡材料的凝胶率和力学性能。结果表明,DCP/TAIC交联体系使PP的抗流淌时间平均延长了6-7min;当DCP为1.4份时,PP发泡材料的最大凝胶率提高14%,拉伸强度和撕裂强度分别提高了24.5%和55.8%。偏光显微镜观察结果显示,在DCP/TAIC交联体系作用下,PP发泡材料表面光滑,泡孔细密且均匀一致。 相似文献
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采用动态硫化法制备POE/PP共混型热塑性弹性体,研究了交联剂过氧化二异丙苯(DCP)用量对POE/PP体系熔体流动速率和力学性能的影响.并用配方优化系统(RCAD)对DCP和助交联剂做了变量分析,考察DCP/S和DCP/TAIC不同配比对体系物理性能的影响。结果表明,DCP的加入使体系中PP降解,体系熔体流动速率单调上升、力学性能下降。DCP用量在一定范围内。助交联剂硫黄S对POE/PP体系才有较好的补强作用,固定DCP用量为2-4份,S用量范围为0.1~0-46份时,体系拉伸强度可达13.9MPa。当DCP用量超过2.0份,TAIC对强度的影响不大,DCP用量为1.72份,TAIC用量在2.44~3.0份时.体系的拉伸强度较好。 相似文献
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研究了新型酰胺类β成核剂对聚丙烯(PP)结晶性能的影响。用差示扫描量热计(DSC)和X射线衍射仪(XRD)对其结晶形态进行了表征,DSC研究表明,该成核剂的加入可以诱导PP中α晶向口晶转变;X射线衍射研究发现,当成核剂加入质量分数为0.3%时,β晶型的相对含量可达到87%,与DSC的研究结果一致。考察了冷却速率对结晶温度和结晶峰温度的影响,结果表明该成核剂的加入使PP结晶向高温方向偏移,结晶速度加快。 相似文献
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聚丙烯熔体流动指数与分子量及其分布的关系 总被引:2,自引:2,他引:0
研究了聚丙烯(PP)的熔体流动指数(MI)与聚合物不同分子量之间的关联性,对于分子量分布较窄的PP,数均分子量(Mn)、重均分子量(Mw)和粘均分子量(Mv)均能较好的关联;反之,MI与Mn关联性下降,而MI与Mn和Mv的关联性仍很好,尤其是MI与Mv的关联性受分子量分布的影响很小;MI与Z均分子量的关联性很差。同时.确定了MI与各种分子量之间的关联式,该式用于本体PP工艺反应器内氢气浓度的计算和MI的预测,与实验测量结果吻合良好。 相似文献
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G. Padmavathi M. G. Mandan S. P. Mitra K. K. Chaudhuri Shital J. Patel S. P. Dabke 《应用聚合物科学杂志》2005,96(5):1611-1618
Molecular weight distribution, which is characterized by its averages like number average (Mn) and weight average (Mw), is one of the important properties of polybutadiene rubber (PBR), and it is difficult to measure. The objective of this work is to develop models to predict Mn and Mw from readily available process variables. Neural networks that are capable of mapping highly complex and non‐linear dependencies have been adapted to develop models for the Mn and Mw of PBR. The molecular weight distribution and its averages of PBR samples collected over a wide range of operating conditions were measured by the conventional Gel Permeable Chromatograph (GPC) method. Neural networks were trained with relevant data to predict Mn and Mw from process variables. The trained networks were found to generalize well when tested with new data. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 96: 1611–1618, 2005 相似文献
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The molecular weights of the industrial-grade isotactic polypropylene (i-PP) homopolymers samples were determined by the melt-state rheological method and effects of molecular weight and molecular weight distribution on solid and melt state creep properties were investigated in detail. The melt-state creep test results showed that the creep resistance of the samples increased by Mw due to the increased chain entanglements, while variations in the polydispersity index (PDI) values did not cause a considerable change in the creep strain values. Moreover, the solid-state creep test results showed that creep strain values increased by Mw and PDI due to the decreasing amount of crystalline structure in the polymer. The results also showed that the amount of crystalline segment was more effective than chain entanglements that were caused by long polymer chains on the creep resistance of the polymers. Modeling the solid-state viscoelastic structure of the samples by the Burger model revealed that the weight of the viscous strain in the total creep strain increased with Mw and PDI, which meant that the differences in the creep strain values of the samples would be more pronounced at extended periods of time. 相似文献
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Static and dynamic light scattering experiments were performed to characterize the copolymer of tetrafluoroethylene (TFE) and perfluoromethyl vinyl ether (PMVE). Solvents of perfluoro‐2‐butyltetrahydrofuran (FC‐75) and Flutec PP11 (PP11) were used to dissolve the TFE‐PMVE copolymer. By taking advantage of the solvent properties of FC‐75 and PP11, homogeneous TFE‐PMVE copolymer solutions were specially prepared in a FC‐75/PP11 mixed solvent. Such prepared solutions could provide a strong enough scattered intensity for light scattering studies. The molecular weight, molecular weight distribution, chain dimensions, and conformation were determined for the TFE‐PMVE copolymer in the FC‐75/PP11 mixed solvent. A combination of viscosity and molecular weight measurements enabled the calculation of the k value in the relation of η0 = k (Mw)3.4 and thus the prediction of the molecular weight of a given TFE‐PMVE copolymer with the same composition by using only the simpler and more readily available rheological measurements. © 2000 John Wiley & Sons, Inc. J Appl Polym Sci 77: 733–739, 2000 相似文献
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