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61.
Jürgen Schellenberg 《大分子材料与工程》2005,290(8):833-842
Summary: The effect of impurities on the coordination polymerization has generally been classified and discussed in different ways and has been investigated in detail in the syndiospecific homo‐ and copolymerization of styrene. With regard to impurities of styrene, phenylacetylene as an unpolar impurity containing separate multiple bonds, 1‐phenyl‐1,2‐ethanediol and ω‐hydroxyacetophenone as examples of polar impurities, and ethylbenzene as an other unpolar impurity have been investigated regarding the effect on the polymerization rate and the influence on the molecular properties of the syndiotactic polystyrenes. In the syndiospecific copolymerization with p‐methylstyrene, indene shows a different behavior regarding the decrease of the polymerization conversion depending on the comonomer concentrations present in the monomer mixture. Additionally, the effect of impurities of the catalyst system on the syndiospecific styrene polymerization has been demonstrated, particularly of octahydrofluorene as a component of the transition metal compound and of trimethylaluminium as a component of the cocatalyst methylaluminoxane. All results have been discussed with respect to the mechanisms of the effects on polymerization behavior and on polymer properties.
62.
综述了洗发、护发二合一香波的功能添加剂。从消费者对产品的诉求着手,介绍了改善泡沫润滑感、泡沫稳定性的非离子水溶性聚氧乙烯醚聚合物,改善头发干、湿梳理性及柔软性的阳离子聚合物、阳离子表面活性剂和聚二甲基硅氧烷,维持香波在货架期内稳定的悬浮稳定剂、防腐剂,以及赋予洗发、护发二合一香波附加功能的去屑成分、防晒成分和头发营养滋润成分等。 相似文献
63.
由于恐怖分子利用邮政系统投寄携带炭疽病毒的邮件,传播病毒,已引起美国政府在邮政系统,选择地利用电子辐射杀死病毒。然而,这种病毒袭击并没有得到有效控制,却使信封内的邮件由于高温辐射,受到损坏。有报道说,由于电子辐射使纸张、珠宝、信用卡、软盘和光盘及其它电子材料受到损害。某些研究已在法庭科学中得到验证。本文介绍辐射过程在渗透和非渗透性客体上,对化学试剂、生物酶记录指纹信息的影响。 相似文献
64.
山梨醇类聚丙烯成核剂的开发与应用研究进展 总被引:7,自引:1,他引:7
综述了山梨醇类聚丙烯成核剂产品在国内外的开发进展,介绍了该类成核剂在聚丙烯中的应用和效果,及其作用机理。 相似文献
65.
EPDM foam was prepared by dynamically vulcanizing EPDM compound in a HAAKE rheometer firstly, then mixing the partially precured EPDM compound with a blowing agent and a sulfur vulcanizing system on a two roll mill. The compound was extruded through a cold feed extruder, and the extrudate was foamed in a circulating hot air oven. EPDM compound was vulcanized partly in the HAAKE rheometer, the final torque increases with increasing sulfur content. Rheological measurement shows the dynamic storage modulus, the loss modulus, and the complex viscosity of precured EPDM compound increase with increasing sulfur content. Then the partially precured EPDM compound was compounded with a blowing agent and a sulfur vulcanizing systems, Rheometric measurement shows that the rate of vulcanization of partially precured EPDM compound is not affected by the precure. The blowing results show that the foam processibility could be improved and the expansion ratio increases in the same processing condition for optimum partially precured EPDM compound, which indicates the optimum crosslink density for EPDM could enhance the efficiency of blowing agent AC. SEM shows that the foam articles have a closed‐cell structure with few open cells, and the large cells inlay among the small cells. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 101: 3387–3394, 2006 相似文献
66.
银系无机抗菌剂的研究进展 总被引:17,自引:1,他引:17
本文综述了银系无机抗菌剂的抗菌机理,类型,制备工艺和应用现状及其抗菌性能评价的方法,探讨了银系无机抗菌剂的发展趋势。 相似文献
67.
68.
Colloidal silica particles are prepared via a sol gel technique carried out in an inverse microemulsion of water in a toluene solution of tetraethoxysilane (TEOS), stabilized by either an anionic surfactant AOT or isopropanol. Functionalized material was obtained using a functional coupling agent (RO)3Si(CH2)3
X, X being a functional group such as methacryloyl, thiol, vinyl, amino group, or a chlorine atom. Functionalization can be carried out either directly via the direct copolycondensation of TEOS and the coupling agent, or in a two-step process involving a core-shell polycondensation of the coupling agent onto preformed silica particles. Kinetic studies of the copolycondensation are carried out using either29Si NMR analysis or liquid chromatography. They show that the consumption of TEOS is more rapid than that of the coupling agent. The materials are characterized both chemically (elemental analysis, FTIR,13C and29Si NMR CPMAS analysis), and by their particle size. The silica functionalized with a polymerizable methacryloyl group is encapsulated by a polymer layer in an inverse emulsion polymerization of acrylic acid. After inversion of the emulsion in water, the resulting material is covered with a layer of hydrophobic polymer in a conventional emulsion polymerization. 相似文献
69.
70.