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中国石油化工股份有限公司开发出一种超高分子量聚乙烯催化剂及其制备方法。该超高分子量聚乙烯催化剂先由卤化镁与烃类溶剂反应,再加入醇化合物,与卤化镁化合物形成醇镁化合物,再依次加入给电子体l、卤代烷基铝、给电子体Ⅱ最后生成中间产物,对中间产物进行超声波处理后,加入钛化合物进行载钛反应,最后干燥制得。 相似文献
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主要讨论了超高分子量聚乙烯(UHMWPE)对聚丙烯(PP)的力学性能的影响,并用DSC考察了UHMWPE含量对材料的熔融和结晶行为的影响。 相似文献
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采用扫描电子显微镜、激光粒度仪、密度仪和熔体流动速率仪(MFR)等研究了2种丙烯聚合用球形齐格勒-纳塔(Ziegler-Natta)催化剂(记为1#和2#)的性能。结果表明:与2#相比,1#的平均粒径更小,粒径分布更宽,活性更高,对氢气更敏感,且所得聚丙烯(PP)堆积密度更高,但PP颗粒粒径较小。不同外给电子体对丙烯聚合的影响不同。采用二环戊基二甲氧基硅烷为外给电子体时,2种催化剂活性均最高,所得PP的MFR均最小。 相似文献
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采用实验室自制的两种复合型氧基硅烷内给电子体:二甲基二(2-酚基乙氧基)硅烷(IED1)和二甲基二(2-氯乙氧基)硅烷(IED2),将两种内给电子体配置Ziegler-Natta催化剂并进行乙烯的催化聚合以制备超高分子量聚乙烯(PE-UHMW)。考察了两种内给电子体加入对Ziegler-Natta催化剂的载钛量、催化剂活性、催化剂的微观形貌及聚合物分子量等因素的影响,并考察催化剂加入量、聚合温度、聚合时间、助催化剂加入量对PE-UHMW聚合效果的影响。由于IED1结构中含有4个含氧基团,电子云密度高于IED2,因此IED1对催化剂活性以及聚合物分子量影响较大。最终确定PE-UHMW聚合工艺条件为:以IED1为内给电子体,催化剂加入量为12 mg/L,IED1与载体氯化镁的物质的量之比为1∶4,聚合温度为75℃,聚合时间为2 h,催化剂中Al/Ti物质的量之比为80。在此工艺条件下催化剂的催化效率为17.1 kg/(g·h),催化剂载钛量为5.8%,PE-UHMW堆密度为0.3 g/cm3,PE-UHMW分子量为4.0×106。 相似文献
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通过逐级放大(10L、150L、1m~3)的淤浆法聚合制备UHMWPE的工艺试验,优化了工艺条件与催化剂(MgCl_2—TiCl_4—ED体系)组成。lm~3中试装置生产的UHMWPE产品,分子量达500万,堆积密度为0.36g/cm~3~0.40g/cm~3;催化剂效率大于50×10~4gPE/gTi;产品机械性能数据与德国Hoechst公司的Hostalen产品相似。 相似文献
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超高分子量速溶聚丙烯酸钠的合成与应用 总被引:2,自引:0,他引:2
主要研究了超高分子量速容型聚丙烯酸钠的合成工艺条件,抗交联剂对其分子量,溶解性能的影响,以及在氯碱行业作为盐水杂质助沉剂的应用效果。 相似文献
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Junting Xu Linxian Feng Zhengxi Liu Linshen Chen Yi Deng Chunming Cui Wei Chen 《应用聚合物科学杂志》1999,71(6):897-901
Syndiotactic polypropylene (s‐PP) was prepared by metallocene catalyst and was fractionated with the temperature rising elution fractionation (TREF) technique. The nonisothermal behavior of the obtained fractions was investigated. Fractions was first cooled at different rates and then heated at a constant rate. The parameters such as the peak crystallization temperature (Tc), the onset crystallization temperature (Ton), the difference between Ton and Tc (ΔT1 = Ton − Tc), the crystallization enthalpy (ΔH), the peak melting temperatures (Tm1, Tm2), and the difference between the Tm1 and Tm2 (ΔT2 = Tm2 − Tm1) were obtained. The dependence of these parameters on cooling rate, syndiotacticity, and molecular weight was discussed. It is found that Tc, Ton, ΔH, Tm1, and Tm2 systematically increase with increasing syndiotacticity and are depressed on increasing the cooling rate. Cooling rate, syndiotacticity, and molecular weight show different influences on ΔT1. In the melting process of s‐PP, double peaks were observed. © 1999 John Wiley & Sons, Inc. J Appl Polym Sci 71: 897–901, 1999 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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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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Bulk polymerization of styrene (St) with an in‐situ‐activated Ziegler‐catalyst containing neodymium 2‐ethylhexyl phosphonate [Nd(P204)3], magnesium–aluminum alkyls and hexamethyl phosphoramide (HMPA) was studied. The new rare‐earth catalyst exhibited high activity for polymerization of styrene, and its catalytic efficiency reached 14 730 g PSt/g Nd. The influence of reaction parameters, such as Mg/Nd, Mg/Al, St/Nd molar ratios, temperature, etc, on the catalyst performance was examined in detail. The molecular weight of the resulting polystyrene is ultra‐high (MW = 40 × 104 ∼ 120 × 104 g mol−1) and the distribution of molecular weight is broad (MW/Mn = 2.1 ∼ 2.8). The microstructure of the polystyrene was characterized by IR and 13C NMR spectroscopies and found to be atactic. © 2001 Society of Chemical Industry 相似文献
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Z-N催化剂生产宽/双峰MWD聚乙烯的研究进展 总被引:5,自引:0,他引:5
介绍了Ziegler-Natta(Z-N)催化剂在单反应器中生产宽,双峰相对分子质量分布(MWD)聚乙烯(PE)的最新研究进展,概括了Z-N催化剂制备宽/双峰MWDPE的主要方法及特点,即传统的Ti系催化体系生产的双峰PE的MWD较窄,改进的Ti-V双金属催化体系活性高,可以调节MWD,但反应操作难度大。通过加入不同的配合物,调节并改进PE的MWD,取得了较好的实验结果。宽/双峰MWDPE的生产和开发是PE工业发展的一个重要方向。 相似文献
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用工业非均相Ziegler-Natta催化剂通过实验室制备和工业生产获得等规聚丙烯(i PP),利用高温凝胶渗透色谱仪、差示扫描量热仪等对i PP进行分析表征。在聚合温度分别为60,70℃条件下,研究了H2、外给电子体环己基-甲基-二甲氧基硅烷(CHMMS)对i PP相对分子质量及其分布、立构规整性及结晶性能等的影响。结果表明:H2,CHMMS对i PP微观结构的影响与聚合温度有很大关系;在不加CHMMS、聚合温度为60℃时,加入H2使i PP全同立构五单元组序列结构含量从60.16%增至77.45%;H2和CHMMS通过影响丙烯分子的"头-头"或"头-尾"结合方式对i PP的微观立体缺陷分布有调整作用。 相似文献
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Ultimate mechanical properties of polyethylene fibers were measured. Results are in close agreement with the stress-induced melting theory of fracture (for finite molecular weight polymers). The perfect fiber work of rupture Wc, modulus Kc, strength σc, and strain c are found to be Wc=0.084±0.003 GPa; σc=7.5 GPa; Kc=335±12 GPa; c=0.0225±0.0005. The activation energy of fracture is measured as ≈108 kJ/mol—the activation energy of polyethylene fusion and one-third the activation energy of bond scission. Non-uniformity of fibers necessitates averaging properties over several test lengths. Actual stress-strain curves are decomposed into thermodynamic and irreversible components. Fusion theory applies to the thermodynamic component.. 相似文献