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聚酰胺共混改性的新进展 总被引:4,自引:0,他引:4
综述了近年来聚酰胺共混改性的新进展,指出反应增容技术促进了聚酞胺与PE、PP等非极性聚合物的共混,并广泛介绍了PA/ABS、PA/E、PA/IP、PA/PAE、PA/PPO、PA/PPTA等新品种聚酰胺共混体系的特性及应用前景。 相似文献
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合成并表征了具有芳香酮侧链结构的苯甲酰基聚苯乙烯(BPS),讨论了反应时间、温度、溶剂、催化剂及投料比对聚苯乙烯(PS)转化为BPS的转化率和交联反应的影响,结果表明,PS在合适条件下可转化成BPS,PS转化成BPS后其UV吸收强度明显增大 相似文献
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本文介绍了适于PVC电缆料生产的PVC树脂、增塑剂、稳定剂、填充剂、润滑剂、差色剂等原辅料,介绍了PVC电缆料配方的设程序、设计要点及实验方法,列举了60℃PVC电缆料、70℃PVC电缆料、PVC易撕电缆料等等PVC电缆料实例。 相似文献
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丙烯酸树脂改性的水性聚氨酯结构设计及表征 总被引:11,自引:2,他引:9
设计聚氨酯(PU) 、丙烯酸树脂( PA)2 种树脂的机械共混、化学共混即核- 壳型聚合过程,及设计该2 种树脂分子链之间形成的化学键,研究了用丙烯酸树脂改性的水性聚氨酯。分析乳胶粒大小及分布、胶膜材料红外光谱及DSC 特征曲线表明:设计PU 分子链硬段与PA 分子链形成化学键,得到的材料中PUA 及PU/PA 中PU 分子链硬段与PA 分子链具有较高的相容性和共混程度;核- 壳型聚合得到的PUA 及PUA′材料PU 分子链与PA 分子链之间处于一定的微相分离状态;机械共混物PU/PA 中PU 分子链、PA 分子链之间的共混主要集中于PU 乳胶粒、PA 乳胶粒表层。 相似文献
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综述了乙丙橡胶(EPDM)与其它橡胶并用材料的研究开发情况,分析了不同并用胶体系和EPDM/NBR、EPDM/NR、EPDM/IIR等的性能、技术关键、存在的问题及应用领域。并针对国内EPDM的现状.提出了研究开发的建议。 相似文献
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LDPE/EPDM共混料发泡工艺探讨:I.发泡剂AC,交联剂DCP对发泡工 … 总被引:3,自引:1,他引:2
重点讨论了发泡剂AC、交联剂DCP对低密度聚乙烯/三元乙丙橡胶(LDPE/EPDM)发泡工艺的影响。探讨了在发泡过程中AC、DCP分解曲线变化,泡体凝胶率、密度的变化与AC及DCP用量之间的关系。 相似文献
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阻隔性HDPE/MPE/PA1010共混体系的研究 总被引:3,自引:0,他引:3
用挤出法以马来酸酐(MAH)接枝高密度聚乙烯(HDPE)为增容剂(MPE),PA1010为阻隔组分,HDPE为基料,制取了HDPE/MPE/PA1010共混材料。研究了挤出温度、MPE用量、PA1010含量对其阻隔性能的影响,比较了几种不同渗透体系的吸油率和渗透损失量。 相似文献
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The optical properties of foreign metal submonolayers formed on Au, Ag, Cu, Pt and Pd electrodes through the underpotential deposition have been investigated by specular reflectivity measurement. Based on the spectral characteristics, 14 adsorbate-substrate systems were classified into 2 groups. The first group, involving Bi on Au, Cu on Au, Pb on Au, Tl on Au, Tl on Ag and Cd on Cu, is characterized by the similarity of the optical properties of the adsorbed metal in the submonolayer to those of bulk metal. The first monolayer was found to form through several submonolayer stages, in which the optical constants are slightly different from each other. In the second group, involving Cd on Au, In on Au, Sn on Au, Ag on Pt, Bi on Pt, Cu on Pt, Pb on Pt and Bi on Pd, the spectra of submonolayer observed experimentally differ from those calculated with the assumption that the optical properties of adatom and substrate are the same as those of corresponding bulk metal. The difference in the work functions between adsorbate and substrate materials in this group is larger than those in the first group.From these findings, some considerations were made to interpret the origin of the specular reflectance change due to the presence of metal adlayer on the electrode surface. The results allow a tentative conclusion that the reflectivity change is predominantly attributed to the optical properties of the adsorbed submonolayer, but at the same time the work function of the substrate and the interband transition in visible should also be taken into consideration. 相似文献
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《Electrochimica acta》1985,30(4):485-491
The adsorption and electrocatalytic properties of the microdeposits of rhodium on gold, palladium on niobium, ruthenium and osmium on titanium, and palladium thin films on glass carbon and nickel have been investigated. It is shown that hydrogen adsorption on rhodium and ruthenium microdeposits is characterized by a low binding energy and that on palladium films by a high binding energy. The cathodic hydrogen evolution rate on ruthenium microdeposits and palladium films on glass carbon and nickel is lower than that on the corresponding bulk metals. These results are consistent with the assumption of the predominant effect of the electronic interaction between microdeposits and thin films on the one hand and the supports on the other, which affects the hydrogen adsorption energy parameters. 相似文献
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Twenty-four oxygenated cholesterols and structurally related compounds were analyzed by high performance liquid chromatography
with silicic acid column and various mobile phases. Hexane–propanol was superior to hexane/tetrahydrofuran and hexane/ethyl
acetate for the separation of oxygenated cholesterols. The retention volumes of oxygenated cholesterols depended on the characteristics
of the substituting group, its position of substitution, as well as its orientation. The effect of various functional groups
at different positions on cholesterol molecules, in general order of decreasing retention volumes, were: hydroxy on the ring,
carbonyl on the ring, epoxy on the ring, hydroxy on the side chain, and carbonyl on the side chain. Synergistic effect of
multiple hydroxyl substitutions on cholesterol was observed. 相似文献
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《Cement and Concrete Research》1987,17(5):715-722
The reduction in mixing water of the concrete, caused by the addition of a superplasticizer, depends also on the type of cement used. Superplasticizer based on naphthalene sulfonated polymer acts much more effectively on cement containing gypsum dihydrate than on that containing calcium sulfate hemihydrate. Moreover, an improvement of the superplasticizer quality caused by ultrafiltration of the polymer, is more effective on the cement containing gypsum than on that with hemihydrate. 相似文献
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This study was designed to address whether applications of methyl jasmonate (MJ) or Benzothiadiazole (BTH) to cultivated tomato, Lycopersicon esculentum, induced elevated densities of defense-related glandular trichomes on new leaves. Four-leaf tomato plants were sprayed with MJ, BTH, or control solutions, and the density of type VI glandular trichomes on new leaves was subsequently determined at 3, 7, 14, 21, and 28 d. At 7, 14, and 21 d, the density of type VI glandular trichomes on new leaves was significantly higher on MJ-treated plants than on BTH- or control-treated plants. At 7 and 14 d after treatment, the mean density of glandular trichomes on new leaves of MJ-treated plants was ninefold higher than on leaves of control-treated plants. We observed entrapment of immature western flower thrips in trichomes on MJ-treated plants at higher rates than on BTH or control plants. Studies to evaluate potential trade-offs between reductions in pest populations by increased trichome density and possible negative impacts of trichome induction on biological control agents are needed. 相似文献
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In an earlier paper [1], the influence of flow rate, ramp (constant rate of temperature rise) and package density on the rates of dyeing of two basic dyes on Ex/an, and on the levelness obtained in the resulting dyeings, was investigated, and a relationship was derived to link these factors quantitatively. This work has now been extended to cover the behaviour of various basic dyes on Exlan and other acrylic fibres, under conditions expected to give borderline levelness. It has been shown that the shape of the rate–of–dyeing curve depends on the type of acrylic fibre and, to a lesser extent, on the cationic retarder used, but not on dye type within the group of CV2. 5–3. 5 basic dyes examined. The response of dyeing rate and degree of unlevelness to deliberate variations of ramp, as demonstrated in the previous work on Exlan, is now confirmed on Cashmilon. Evidence of a different type of random unlevelness, not related directly to dyeing rate, was also obtained from dyeings on the various fibres at a slow ramp. 相似文献
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结合课程教学现状和实践教学环节,分析了教学中存在的问题。以CDIO教育模式为基础,对"玻璃工艺学"课程教学内容进行了初步改革探索,将理论教学与实践环节有机融合为一整体,培养学生的综合实践与创新能力。 相似文献