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Surface modification of poly [1-(trimethylsilyl)-1-propyne] (PTMSP) membranes bybromine vapor has been studied. It is shown that Br/C atomic ratio at the surfaces increased withthe time of bromination until about 60 min, then it reached a plateau. The results of XPS and IRstudies indicated that the addition of bromine to double bonds and the replacement of H on CH_3 bybromine had taken place so that a new peak at 286.0 eV (C--Br)in C_(1s) spectra and some newbands, e. g. at 1220 and 580cm~(-1) in IR spectra were formed. The fact,t Po_2, permeability ofoxygen, decreased and α_(O_2/N_2), separation factor of oxygen relative to nitrogen, increased withbromination time, shows that surface modification of PTMSP by bromine may be an efficient approach to prepare PTMSP membranes used for practical gas separations. 相似文献
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A series of polyimide fibers containing phosphorus element derived from (3-aminophenyl) methyl phosphine oxide (DAMPO) diamine was exposed to an artificial atomic oxygen environment which simulated the space environment in low earth orbit (LEO). The mass loss, surface morphology, chemical composition, and mechanical properties of the fibers before and after atomic oxygen (AO) exposure were compared in detail with a blank sample. Results showed that the phosphor-containing fibers demonstrated lower mass change and less tensile strength reduction. SEM results showed that the fibers with phosphorous element had relatively dense surface after AO exposure. Meanwhile, XPS results indicated that a passivated phosphate layer, which could protect the following under-layer from attacking by AO, was formed on the surface of the fibers. These results indicated that the incorporation of diamine (DAMPO) into the main chains could protect the fibers for avoiding further erosion from AO exposure. Hence, the phosphor-containing PI fibers exhibits potential application in space fields. 相似文献
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电子反常供需型Diels-Alder反应(inverse electron demabd Diels-Alder reaction,IDA)因其在天然生物碱及类似物合成中的应用,在近20年来已经逐渐引起关注[1].含氮芳杂环体系1,2,4-三嗪由于其特有的缺电子特征,作为双烯体非常适于进行这类反应[2].本文利用IDA反应从3-吡啶基-5,6-二取代-1,2,4-三嗪出发,设计出一条简捷、低成本的合成路线,成功地合成出不对称取代的2,3′-联吡啶和2,4′-联吡啶.这一类化合物已被应用于药物中间体或有机配体. 相似文献
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沙利度胺(1)最早是由德国的一家制药公司在20世纪50年代上市的一种用于镇静和孕妇止吐的药物,当时被认为是一个毒性很小的药物,但是很快就发现这个药物有非常强的致畸性,于是在1962年这个药物撤出了市场。后期研究结果表明,沙利度胺的致畸性是由其5-异构体导致的, 相似文献
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综合2,5-二氨苯基嘧啶(PRM)的刚性结构特征和配位化学特征以及二苯醚二胺(ODA)的柔性结构特征,制备出一系列性能可控的含嘧啶聚酰亚胺.含嘧啶聚酰亚胺的玻璃化转变温度、热稳定性、拉伸强度和模量等,均随聚酰亚胺中PRM比例的升高而增加.但热膨胀系数却随PRM比例的增加而降低,当PRM和ODA的比例为1∶1时,热膨胀系数为17×10-6K-1,与铜箔的热膨胀系数一致,可与铜箔形成尺寸稳定的无胶挠性覆铜板;同时,这一比例的含嘧啶聚酰亚胺与铜箔的粘结强度也达到最高(17.3 N·cm-1).这种含嘧啶聚酰亚胺的性能可以满足无胶挠性印制电路对基底膜材料的尺寸稳定性和粘结性能的要求. 相似文献
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In this study, polyimide fibers at different stages of imidization were characterized by TGA, DSC, and FTIR. The imidization degree(ID) calculated by TGA was based on the weight loss of each sample, which was caused by the imidization of residual amic acid groups. The results of TGA showed good regularity with the thermal treatment temperature of the PI fibers. For DSC, the ID was calculated based on the area of endothermal peak of each sample. Compared with TGA, DSC showed a relatively higher value because the endothermal peak was reduced by the exothermic re-formation of polyamic acid which may be partially degraded during thermal treatment. The IDs obtained by the FTIR spectra generally showed poorer regularities than those obtained by both TGA and DSC, especially for the results calculated using the 730 cm-1 band. Based on the 1350 cm-1 band, the obtained IDs showed better agreement with the TGA or DSC results. The results obtained by these three methods were compared and analyzed. The ID obtained by TGA showed much more reliability among these three methods. 相似文献