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91.
本文制备了一系列不同色浆质量分数的水性聚氨酯涂料,并将其喷涂在汽车仪表板聚氯乙烯(PVC)表皮的背面形成复合材料。 用旋转流变仪表征了涂料的粘度以评价其喷涂性能;用差示扫描量热仪表征了材料的玻璃化转变温度(Tg);利用万能材料试验机表征了材料在-30 ℃条件下的拉伸性能及抗撕裂性能;用动态热机械分析仪表征了材料的损耗比随温度的变化。 结果表明:不同色浆质量分数的涂料都能喷涂,含有涂层材料PVC表皮在-30 ℃低温爆破性能与涂层材料的Tg、低温拉伸性能、抗撕裂性能的关系并不大,而与涂层材料的阻尼性能直接相关。 材料的阻尼性能越好,其低温爆破性能越好。 相似文献
92.
In order to improve the performance of inorganic/organic composites, aluminum trihydroxide (ATH) core composites with a styrene‐ethylene‐butadiene‐styrene block copolymer grafted with maleic anhydride (MAH‐g‐SEBS) shell phase, and P‐N flame retardant as a synergistic agent, were prepared through an interface design. The effects of polyethylene glycol (PEG) content on the interfacial interaction, flame retardancy, thermal properties, and mechanical properties of high‐density polyethylene (HDPE)/ATH composites were investigated by small angle X‐ray diffraction, rotational rheometer, limiting oxygen index, thermogravimetric analysis (TGA), and tensile testing. The ATH synergistic effects of P‐N flame‐retardant improved the combustion performance of HDPE/ATH/PEG(3%)/MAH‐g‐SEBS/P‐N (abbreviated as HDPE/MH3/M‐g‐S/P‐N) composite by forming more carbon layer, increased the elongation at break from 21% to 558% compared to HDPE/ATH, and increased the interface thickness from 0.447 to 0.891 nm. SEM results support the compatibility of ATH with HDPE increased and the interfacial effect was enhanced. TGA showed the maximum decomposition temperature of the two stages and the yield of the residue at high temperature increased first and then decreased with the increase of PEG content. Rheological behavior showed the storage modulus, complex viscosity, and the relaxation time initially increased and then decreased with the increase of PEG content indicating PEG, M‐g‐S, and ATH powder gradually formed a partial coating, then a full coating, and finally an over‐coated core‐shell structured model. 相似文献
93.
J. Liu T.-C. Long P. H. Geil F. Rybnikar 《Journal of Polymer Science.Polymer Physics》1996,34(17):2843-2851
Single crystals of poly(terephthalic anhydride) (PTA) have been grown using the confined thin film melt polymerization technique. Thin lamellae (ca. 50 Å) are found for low polymerization temperatures, with thick crystals forming for polymerization at 200°C. Shearing of the material shortly after the initiation of polymerization at 200°C yielded single crystal domains composed of fibrillar texture material; these samples gave [010] zone ED patterns complementing the [001] zone patterns from the unsheared CTFMP samples. A monoclinic, single chain, two repeat unit, unit cell (Pc11) is proposed based on four different electron diffraction zone patterns: a = 6.01 Å, b = 3.945 Å, c = 14.11 Å, α = 106.9°. Simulations, using the Cerius2 program, of the corresponding molecular conformation, packing and electron diffraction (ED) patterns were performed; the ED simulations are in good agreement with the observed patterns. An R-factor of 0.23 is obtained based on a comparison of calculated and observed structure factors for the 39 independent ED reflections observed on the different zone patterns. © 1996 John Wiley & Sons, Inc. 相似文献
94.
Yi-Feng Wang Kwok P. Chan Allan S. Hay 《Journal of polymer science. Part A, Polymer chemistry》1996,34(3):375-385
Facile ring-opening polymerization of cyclic aryl ether oligomers containing the 1,2-dibenzoylbenzene moiety to form high molecular weight linear polymers in the presence of a nucleophilic initiator is described. The polymerization can be initiated in the melt in the presence of a nucleophilic initiator such as potassium carbonate, cesium fluoride, and alkali phenoxides. Various alkali phenoxides were investigated as potential nucleophilic initiators. The polymerization reaction rate in the melt increases in the order of K+ > Na+ > Cs+, and in the order of −OPhPhO− > PhO− > PhOPhO− > PhPhO−. However, the polymerization in an aprotic dipolar solvent is faster in the presence of cesium phenoxide than in the presence of potassium phenoxide. Polymerization of the cyclic oligomers in solution demonstrates that the ring-opening polymerization proceeds via a chain-growth mechanism and involves a transetherification reaction between linear and cyclic aryl ether oligomers. The ring-chain equilibrium is much more favorable towards linear polymers. Since little or no ring strain exists in the cyclic system, the transetherification reactions are indiscriminate with regards to cyclic or linear chains and the interchain equilibration is also a facile process during polymerization. This intermolecular transetherification has been demonstrated by using low molecular weight aryl ethers to control the molecular weight of the polymer formed via ring-opening polymerization. © 1996 John Wiley & Sons, Inc. 相似文献
95.
Giorgio Montaudo Concetto Puglisi Filippo Samperi Francesco Paolo Lamantia 《Journal of polymer science. Part A, Polymer chemistry》1996,34(7):1283-1290
Nylon 6 (Ny6) and Bisphenol A polycarbonate (PC) are immiscible and form biphasic blends. To improve the compatibility of Ny6 and PC several ABA and AB Ny6/PC block copolymers were synthesized, and their compatibilizing behavior on the blends were tested. Block copolymers were prepared by reacting monoamino- or diamino-terminated Ny6 homopolymers with high molecular weight PC at 130°C in anhydrous DMSO. The reaction of diamino- and monoamino-terminated Ny6 with polycarbonate produces block copolymers of the type PC-Ny6-PC (ABA) and PC-Ny6 (AB), respectively, plus a certain amount of unconverted PC degradated to lower molecular weights. To separate the block copolymer from the unconverted PC, a selective fractionation with tetrahydrofuran (THF) and trifluoroethanol (TFE) was carried out. Three different fractions were obtained: THF-soluble fraction, TFE-soluble fraction, and the TFE-insoluble fraction. The scanning electron microscopy (SEM) analysis of a 75/25 (wt/wt) Ny6/PC blend added with 2% of ABA or AB block copolymers, showed the presence of smaller PC particles more adherent to the polyamide matrix, with respect to the same blend nonadded, which is clearly biphasic. The size of the PC particles decreases from ABA to AB compatibilized blends and the adhesion with the matrix is increases in the same way. © 1996 John Wiley & Sons, Inc. 相似文献
96.
97.
98.
1 INTRODUCTION Bauxite porcelain is a novel “K2O–Al2O3–SiO2” system ceramic by using sintered bauxite, clay and potash feldspar and albite as the main raw materials with the Al2O3’s content of 50%~60(massfraction). Compared to the traditional“K2O–Al2O3–SiO2” feldspar porcelain by using quartz, bolus alb and potash feldspar and albite as the main raw materials, the bauxite porcelain possesses such advantages as high mechanical strength, excellent electrical insula- tion prop… 相似文献
99.
在没有溶剂介质参与的高分子聚合反应中,高分子凝聚态的变化与化学反应之间的作用关系变得更加直接。以熔融聚合、反应挤出、固相聚合为代表的高分子树脂无溶剂生产技术是集高分子树脂合成、材料加工制备及工程一体化的新兴科学与技术,是当代材料科学领域发展的前沿领域,代表着高分子树脂生产技术发展的必然趋势。本文将上述这三种典型的树脂工业合成技术及相应机理进行了简要的介绍,并分别以聚对苯二甲酸乙二醇酯(PET)和聚乳酸(PLA)的实际生产研究情况为例,展示三种生产技术之间的相互联系,揭示这三种无溶剂型高分子制备技术过程中出现的高分子凝聚态变化与化学反应之间的基本问题,为广大科研工作提供一些有价值的参考。 相似文献
100.
Electrosynthesis of hafnium diboride from cryolite-alumina melts containing hafnium and boron oxides
S. V. Devyatkin 《Russian Journal of Electrochemistry》2005,41(4):392-394
Electrosynthesis of hafnium diboride from cryolite-alumina melts containing hafnium and boron oxides is studied. Thermodynamic estimation and voltammetric measurements show this process to occur in one-stage. Hafnium diboride coatings on nickel are obtained by electrolysis.__________Translated from Elektrokhimiya, Vol. 41, No. 4, 2005, pp. 448–451.Original Russian Text Copyright © 2005 by Devyatkin. 相似文献