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在分析负载茂金属催化的丙烯气相聚合过程中催化剂颗粒破碎行为基础上,提出了该过程聚丙烯颗粒内部传质与传热物理模型,耦合丙烯聚合本征反应建立了丙烯气相聚合过程的单颗粒模型:改进的多粒模型.采用上述模型得到了丙烯气相聚合过程中聚丙烯颗粒内部的单体浓度、平均温度、颗粒内部的温度梯度以及催化剂活性中心浓度等的变化规律.模拟结果表... 相似文献
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通过广角X射线衍射(WAXD)对由丙烯超临界聚合和传统本体淤浆法制得的等规聚丙烯原生结晶特征进行了研究,并讨论了聚合工艺、预聚温度、粒径、分子量等对原生晶特征的影响。结果表明,超临界聚合法制备的等规聚丙烯(SC-iPP)呈现出α和γ的混合晶型,而采用传统淤浆法制备的等规聚丙烯(C-iPP)只含有单一α晶型,这是因为超临界的高温高压状态,使得体系传热传质阻力较小,更有利于原生晶型的发展。此外,预聚温度、粒径、分子量等因素也对丙烯超临界聚合所制得的SC-iPP结晶特征有显著影响。 相似文献
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综述了以硼化合物为助催化剂的离子茂金属催化剂催化丙烯聚合的研究进展,介绍了用不同催化体系制备的不同结构的聚丙烯的性能及用途,并对聚合机理进行了探讨 。 相似文献
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综述了丙烯聚合用Ziegler-Natta催化剂预聚合的研究进展,包括预聚合对催化剂的影响、预聚合方法及其应用。预聚合可以提高催化剂活性、改善聚合物的颗粒形态、影响聚合动力学行为。现有研究已经开发了不同的预聚合方法,进一步改善了催化剂和聚合物的颗粒形态,提高了聚合物的性能。经过预聚合制备的预聚合催化剂,适用于无预聚合操作单元的气相丙烯聚合工艺,不仅能有效解决聚合物中细粉含量高、聚合物结块等问题,还能获得具有高性能、高附加值的聚丙烯产品。 相似文献
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采用氧化一还原引发体系,以丙烯酞胺、丙烯酸为单体,通过水溶液聚合合成了高分子量的阴离子型聚丙烯酞胺.研究了EDTA用量、反应时间、pH值和AA/AM配比等对聚丙烯酞胺分子量、聚合转化率以及溶解性能的影响. 相似文献
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介绍我国自行开发的聚丙烯连续本体聚合新工艺(SPG PP)具有,丙烯单耗低,能耗低,丙烯单程转化率高,催化剂利用率高,设备生产效率高,对不同催化剂适应性强,产品质量好,单线生产能力大等特点。适用于间歇装置的改造,也适用于新建装置,若能使国内众多间歇本体聚合相继改造成SPGPP工艺生产装置,将使这些装置的生产水平跃上一个新台阶。 相似文献
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Plasma pretreatment has been used to generate reactive radicals and oxygenated groups on polymer surfaces for graft polymerization. The polymer substrates studied were composed of a polypropylene–polyethylene (PP–PE) copolymer, which was predominantly PP, and also contained blended ethylene–propylene rubber (EPR) as either about 15 or about 60 mol %. A pure PP substrate was also studied for comparison. The grafted polymer was polystyrene (PS). Raman microspectroscopic 2‐dimensional mapping was used to elucidate the role of crystallinity and EPR in the plasma treatment and graft polymerization process. It was found that the plasma pretreatment favored the EPR component of the substrate and the graft yield was related to the EPR content. Crystallinity seemed to have a much less significant effect on the grafting reaction. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 88: 1643–1652, 2003 相似文献
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丙烯聚合的Monte Carlo模拟(Ⅰ)活性杂质对丙烯聚合的影响 总被引:2,自引:0,他引:2
A comprehensive mechanism for propylene polymerization was proposed by considering the effects of main impurities in the material on propylene polymerization. According to the proposed mechanism, Monte Carlo simulation was employed to investigate the polymerization kinetics in order to determine the effects of the main impurities on the polymerization. Significant influences of the main impurities on the rate, number-average degree and controlling capability of hydrogen of the polymerization were analyzed. 相似文献
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丙烯聚合的Monte Carlo模拟(Ⅰ)活性杂质对丙烯聚合的影响 总被引:1,自引:0,他引:1
1 INTRODUCTION Polypropylene is a popular thermoplastic polymer, and produced via bulk polymerization in petroleum chemical industry. The molecular configuration of polypropylene and the characteristics of polymer can be controlled by the catalyst and polymerization method. Furthermore, other factors, such as impurities in the material and polymerization conditions, also influence the industrial production. Catalyst influences the rate and the quality of polymer, is a key factor of the in… 相似文献
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研究了C2对称的[Me2Si(2-Me-4-Ph-Ind)2]Zr Cl2双茂锆催化剂在不同条件下对丙烯均聚及丙烯与高级α-烯烃共聚反应的催化特性。研究结果表明:配合物的催化活性随着铝锆比、温度、压力的增加而提高;聚合物数均相对分子质量随着温度的提高而降低,在25℃、1 MPa丙烯压力下,可以获得数均相对分子质量高达40万的等规聚丙烯。该催化体系具有良好的共聚活性,共单体的侧链长度并不影响聚合活性。通过改变共单体的投料比,可控制共聚物中共单体的含量。 相似文献
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The functions of crystallizable ethylene‐propylene copolymers in the formation of multiple phase morphology of high impact polypropylene (hiPP) were studied by solvent extraction fractionation, transmission electron microscopy (TEM), selected area electron diffraction (SAED), nuclear magnetic resonance (13C‐NMR), and selected reblending of different fractions of hiPP. The results indicate that hiPP contains, in addition to polypropylene (PP) and amorphous ethylene‐propylene random copolymer (EPR) as well as a small amount of polyethylene (PE), a series of crystallizable ethylene‐propylene copolymers. The crystallizable ethylene‐propylene copolymers can be further divided into ethylene‐propylene segmented copolymer (PE‐s‐PP) with a short sequence length of PE and PP segments, and ethylene‐propylene block copolymer (PE‐b‐PP) with a long sequence length of PE and PP blocks. PE‐s‐PP and PE‐b‐PP participate differently in the formation of multilayered core‐shell structure of the dispersed phase in hiPP. PE‐s‐PP (like PE) constructs inner core, PE‐b‐PP forms outer shell, while intermediate layer is resulted from EPR. The main reason of the different functions of the crystallizable ethylene‐propylene copolymers is due to their different compatibility with the PP matrix. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012 相似文献
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在MgCl2溶解过程中加入内给电子体,开发了一种新型丙烯聚合用BCZ型催化剂,并在5 L聚合釜中进行了本体聚合考核评价,在12 m3小本体工艺装置上进行工业应用试验,在25 kg/h的连续法Innovene气相工艺装置进行中试试验。研究表明:用BCZ型催化剂制备聚丙烯(PP)时,催化剂活性高出国产同类催化剂近50%,氢调敏感性好,同样氢气用量下,PP的熔体流动速率可提高25%左右;所制PP的相对分子质量分布大于7.5,等规指数高;BCZ型催化剂可用于小本体法工艺、连续法气相工艺装置制备均聚和共聚PP。 相似文献
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国内外乙丙橡胶生产现状及市场分析 总被引:1,自引:0,他引:1
分析对比了乙丙橡胶的几种生产方法,目前世界上乙丙橡胶生产主要采用溶液聚合法。介绍了国内外乙丙橡胶生产、消费现状,并对乙丙橡胶市场进行了分析预测。 相似文献
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就聚丙烯装置的生产情况,分析了影响丙烯聚合反应的几个主要因素。通过降低原料杂质含量,选择合适的催化剂、改性剂、三乙基铝加入比例以及选择合适的反应温度、反应压力等措施来提高聚合反应的效率。 相似文献