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71.
EVA/木质素薄膜的制备与性能研究   总被引:3,自引:0,他引:3  
研究了经造粒、吹塑成膜的乙烯醋酸乙烯酯共聚物(EVA)/木质素共混物的结构、热性能以及力学性能。热重分析表明木质素与EVA共混物的热稳定性比单一组分的高;差示扫描量热分析表明木质素与EVA的相容性好;傅里叶红外光谱分析表明木质素与EVA之间存在分子间氢键相互作用;扫描电子显微分析表明木质素含量对共混物形貌有明显的影响;力学性能测试表明木质素含量在30%(质量分数,下同)以内,共混物薄膜仍具有较好的力学性能,随着木质素含量的增加,共混物力学性能降低。  相似文献   
72.
Knowing that dimethiconols or silanols condense under acid or alkaline catalysis, a study was undertaken to determine if these compounds could be successfully ethoxylated under conditions similar to those used to ethoxylate fatty alcohols and acids. It was anticipated that the condensation reaction would take precedent over ethoxylation reaction. We determined that ethoxylation reaction occurs preferentially to condensation reaction. In addition, kinetics of ethoxylation are similar to kinetics observed when fatty alcohols are ethoxylated. This reaction gives rise to a new class of hydrolyzable silicone compounds that have applications in industrial as well as in personal-care products.  相似文献   
73.
阐述了乙烯原料的世界与我国市场,对未来我国乙烯原料的需求与供应进行了预测。  相似文献   
74.
In this paper, the ethylene adsorption capacities of the nano-sized carbon hollow spheres (CNB) and active carbon (AC), the Pd (PdCl2) impregnated CNB or AC (Pd/CNB, Pd/AC) and heat treatment under various conditions, were studied at different ethylene concentrations from 64 to 1060 ppm. The results indicated that AC had a good ethylene adsorption capacity at high ethylene concentration. Pd impregnation decreased the ethylene adsorption capacity of AC. Heat treatment and H2 activation could increase the ethylene adsorption capacity, but also lowered than AC itself. CNB had lower ethylene adsorption capacity than AC, but heat treatment and H2 activation could increase its ethylene adsorption capacity markedly. With activating condition from heat treatment in N2 at 300 °C to activation in H2/N2 at 100 °C, to activation in H2 at 200 °C, and to activation in H2 at 300 °C, the ethylene adsorption capacity of Pd/CNB was increased regularly. At low ethylene concentration, viz., 64 ppm, the ethylene adsorption quantities (q a) by Pd/CNB activated in H2 at 200 or 300 °C were higher than any other adsorbents. So, activated in H2 atmosphere at higher than 100 °C, Pd/CNB is particularly advantaged for adsorbing low concentration of ethylene. Amongst all the adsorbents used, Pd/CNB activated in H2 atmosphere at 300 °C for 2 h has the highest ethylene adsorption capacity at lower concentration than 125 ppm. In addition, all the CNB, Pd/CNB, AC, and Pd/AC samples can be easily regenerated in airflow for more than 3 h.  相似文献   
75.
Poly(L‐lactide)‐poly(ethylene glycol) multiblock copolymers with predetermined block lengths were synthesized by polycondensation of PLA diols and PEG diacids. The reaction was carried out under mild conditions, using dicyclohexylcarbodiimide as the coupling agent and dimethylaminopyridine as the catalyst. The resulting copolymers were characterized by various analytical techniques, such as GPC, viscometry, 1H‐NMR, FTIR, DSC, X‐ray diffractometry, and contact angle measurement. The results indicated that these copolymers presented outstanding properties pertinent to biomedical use, including better miscibility between the two components, low crystallinity, and hydrophilicity. Moreover, the properties of the copolymers can be modulated by adjusting the block length of the two components or the reaction conditions. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 84: 1729–1736, 2002; DOI 10.1002/app.10580  相似文献   
76.
介绍了EP公司KG乙烯工厂先进的管理经验,提出了搞好企业合理的设想。  相似文献   
77.
E. Martuscelli  M. Pracella 《Polymer》1984,25(8):1097-1106
Results are reported on the influence of composition and molecular mass of components on the isothermal growth rate of spherulites, on the overall kinetic rate constant, on the primary nucleation and on the thermal behaviour of poly(ethylene oxide)/poly(methyl methacrylate) blends. The growth rate of PEO spherulites as well as the observed equilibrium melting temperatures decrease, for a given Tc or ΔT, with the increase of PMMA content.Such observations are interpreted by assuming that the polymers are compatible in the undercooled melt, at least in the range of crystallization temperatures investigated. Thermodynamic quantities such as the surface free energy of folding σe and the Flory-Huggins parameter χ12 have been obtained by studying the dependence of the radial growth rate G and of the overall kinetic rate constant K from temperature and composition and the dependence of the equilibrium melting temperature depression ΔTm upon composition, respectively.  相似文献   
78.
引 言乙烯生产装置的核心部分是管式裂解炉 ,在小口径反应管内进行着湍流流体流动、传质、传热及裂解反应等过程 ,它们高度耦合在一起 ,其内部有许多十分重要的化学工程参数均不易测得 ,这就使得对管式裂解炉运行机制与规律的了解和认识及其性能的优化变得十分困难 .但是 ,乙烯工业的发展所带来的经济效益又迫使人们要了解和掌握这一复杂过程 ,优质高效地设计、操作和优化乙烯管式裂解炉 .近 10多年来 ,利用流动反应数学模型较准确地描述和模拟上述复杂过程 ,证明是管式裂解炉设计改进与优化操作行之有效的途径[1] .乙烯裂解炉反应管的工艺…  相似文献   
79.
Graft polymerization of acrylic acid onto plasma‐treated poly(ethylene terephthalate) (PET) films was used to prepare surfaces suitable for collagen immobilization by dip‐coating. Such surfaces could be used as matrices for smooth muscle cell cultures in tissue engineering. Contact angle measurements showed that plasma‐treated and grafted PET films undergo considerable surface reorganization during storage under ambient conditions. However, after collagen immobilization the contact angle remained relatively stable. The amount of collagen initially attached to the film surface increased with increasing poly(acrylic acid) graft density, but subsequent washing in water led to significant collagen loss. This loss could nevertheless be substantially reduced by thermal crosslinking of the collagen in the range 110–130 °C. Atomic force microscopy (AFM) observations suggested that the washed crosslinked collagen has a very similar structure to that of the un‐crosslinked collagen. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 85: 1874–1880, 2002  相似文献   
80.
茂锆金属催化剂催化乙烯聚合研究   总被引:2,自引:0,他引:2  
主要考察了含锆的茂金属催化剂中催化乙烯反应条件优化研究,在最优条件下催化聚合反应所得的产物与吉林石化公司聚乙烯厂聚乙烯产品进行分析对比.对茂锆金属催化剂催化乙烯聚合反应条件研究表明,适宜的助催化剂[Al]与主催化剂[Cat]的摩尔比在1 500左右,适宜的主催化剂浓度在1.5×10-4 mol/L左右,最佳聚合温度60℃,此时催化剂的活性可达到106 gPE/(molCat·h).从物理性能、热性能、相对支化度、相对分子质量及其分布分析可知,制备出的负载茂锆金属催化剂在最优反应条件下催化乙烯聚合所得的产物与吉林石化公司聚乙烯产品性质基本一致,符合产品的指标,支链分布均匀,分子量分布更窄.同时对茂锆金属催化剂主、助催化剂催化乙烯聚合的作用和机理进行了探讨.  相似文献   
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