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991.
从工艺、设备等方面对生产高密度聚乙烯产品7000F的难点进行了统计分析,主要存在质量不稳定、低聚物量大、易堵塞工艺管线、离心机故障率高、己烷汽提塔系统易堵塞、造粒困难等问题,并对此提出了相应对策。通过技术改造、优化工艺参数等手段,使7000F生产周期在1个月以上,基本达到了长周期稳定生产的目的。 相似文献
992.
993.
本文作者采用色谱—质谱联用法定性地分析了合成的二甘醇单叔丁基醚及其它副产物,并用质谱谱图解析方法确定了它们的结构。 相似文献
994.
R.A. Sperling T. Pellegrino J.K. Li W.H. Chang W.J. Parak 《Advanced functional materials》2006,16(7):943-948
A concept is describe that facilitates the modification of colloidal nanoparticles of different materials with an exactly known number of variable functional groups. In particular, a procedure for the surface functionalization of nanoparticles with a controlled number of mono‐ or bifunctional poly(ethylene glycol) (PEG) molecules of suitable chain length is reported. Conjugates of nanoparticles with one, two, and three PEG molecules per nanoparticle could be separated using gel electrophoresis. Molecules with additional functionalities could be conjugated to the free ends of the bifunctional PEG molecules. In this way the PEG molecules act as convenient spacers that allow for the sorting of nanoparticles with a discrete number of functional groups. 相似文献
995.
996.
Study was made of the compatibilization of polyethylene/aluminum hydroxide (PE/ATH) and polyethylene/magnesium hydroxide (PE/MH) composites with composition 60/40 wt%. Compatibilizers were hydroxyl or carboxylic acid functionalized copolymers prepared in our laboratory with metallocene catalysts and commercial butyl acrylate, maleic anhydride, epoxy, and acrylic acid functionalized polyethylenes. Comparison was made with stearic acid treatment of the composites. The effect of polymeric compatibilizers on the properties of the composites was studied by tensile and impact tests, dynamic mechanical analysis, differential scanning calorimetry, morphology studies, and flammability tests. Adhesion of the PE/ATH and PE/MH composites was significantly improved, as seen in morphology studies in the changed fracture mechanism. The improved adhesion was particularly reflected in the mechanical properties: an improvement in both stiffness and toughness was achieved with use of the functionalized copolymers prepared with metallocene catalysts. According to cone calorimetry, flame retardancy properties of the composites did not deteriorate upon addition of compatibilizers. 相似文献
997.
增强阻燃PET工程塑料的研究 总被引:7,自引:0,他引:7
利用DSC,红外光谱图,电镜照片研究玻璃纤维与PET界面,发现添加30份经偶联剂处理的玻璃纤维可以有效增强增韧PET,玻纤表面处理剂硅烷能显著提高PET工程塑料的力学性能及界面粘结强度。通过阻燃效果分析,8-9份的溴-锑阻燃剂即可使PET/玻纤复合材料的氧指数达27。DSC分析表明玻璃纤维。阻燃剂粒子,滑石粉均起到成核剂的作用。 相似文献
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The isothermal crystallization behavior and morphology of a polypropylene (PP)‐based copolymer, a metallocene‐prepared linear low‐density polyethylene (M‐LLDPE) and their three 10/90, 30/70 and 50/50 M‐LLDPE/PP blends have been investigated. The PP and M‐LLDPE contained 5 ethylene and 3.3 mol% hexene‐1 as a comonomer, respectively. Isothermal crystallization studies revealed a different temperature‐dependence on crystallization for M‐LLDPE, PP and their blends and the crystallization half‐life for the M‐LLDPE was higher than either PP or the blends at a certain temperature. The PP‐rich blends also showed a quite similar crystallization rate to that of PP. Investigations on the variation of spherulite growth rate of PP in the blends at different temperatures revealed no significant change and was quite independent of the amount of M‐LLDPE being employed. The morphology studies revealed that the nucleation densities of the PP spherulites decreased by introducing M‐LLDPE into PP and the M‐LLDPE remained as discrete droplets dispersed throughout the PP spherulites. The results obtained were consistent with no miscibility between the two components. Copyright © 2005 Society of Chemical Industry 相似文献