期刊文献+
共找到5篇文章
< 1 >
每页显示 20 50 100
STUDY ON PYROLYSIS OF POLYPHENYLSILSESQUIOXANE 被引量:1
1
作者 Jun Ma Liang-he Shi +3 位作者 Jian-min Zhang Bai-yu Li De-yan Shen Jian Xu State Key Laboratory of Polymer Physics & Chemistry Center for Molecular Science, Institute of Chemistry,Chinese Academy of Sciences, Beijing 100080 China 《Chinese Journal of Polymer Science》 SCIE CAS CSCD 2002年第6期573-577,共5页
X-ray photoelectron spectroscopy and Raman spectroscopy were' used to determine the chemical change of polyphenylsilsesquioxane (PPSQ) during pyrolysis in flowing nitrogen. Two temperature ranges were found for py... X-ray photoelectron spectroscopy and Raman spectroscopy were' used to determine the chemical change of polyphenylsilsesquioxane (PPSQ) during pyrolysis in flowing nitrogen. Two temperature ranges were found for pyrolysed PPSQ below and above 600degreesC, respectively. The former is related to the rearrangement of PPSQ backbone and the latter reflects that most of backbone structure of PPSQ might be broken down and unorganized. Carbon formed in carbonization of PPSQ sample pyrolysed at 900degreesC should be sp(3) bonded carbon with crystallite size effects or defects. 展开更多
关键词 PYROLYSIS polyphenylsilsesquioxane
下载PDF
TEMPERATURE DEPENDENCE OF THE FLUORESCENCE SPECTRA OF LADDERLIKE POLYPHENYLSILSESQUIOXANE AND LADDERLIKE 1,4-PHENYLENE-BRIDGED POLYVINYLSILOXANE
2
作者 张榕本 《Chinese Journal of Polymer Science》 SCIE CAS CSCD 2002年第1期15-23,共9页
Fluorescence spectra of ladderlike polyphenylsilsesquioxane (LPPS) and ladderlike 1,4-phenylene-bridged polyvinylsiloxane (LPPVS) have been measured as a function of temperature (4-55 degreesC), in dilute tetrahydrofu... Fluorescence spectra of ladderlike polyphenylsilsesquioxane (LPPS) and ladderlike 1,4-phenylene-bridged polyvinylsiloxane (LPPVS) have been measured as a function of temperature (4-55 degreesC), in dilute tetrahydrofuran solution. The excimer (IF) to monomer (I-M) intensity ratio (I-E/I-M) of LPPS dilute solution shows a double linear Arrhenius plot with a break point ascribable to a transition temperature Tt. This behavior has not been found for single chain polyorganosiloxanes. When In/(E) of LPPS was plotted against 1/T, it also gave a double linear plot with one break point, which was found in single chain polyorganosiloxanes. The different behaviors between LPPS and single chain polyorganosiloxanes may be mainly attributed to the relatively rigid double-chain macromolecular backbone of LPPS. However, the 1n(I-E/I-M) of dilute LPPVS solution versus 1/T shows a simple linear variation with a positive slope which confirms our proposition. The difference between the fluorescence results of LPPS and those of LPPVS may possibly derive from their structure differences and cooperative motion in backbone chain bonds. 展开更多
关键词 ladderlike polyphenylsilsesquioxane ladderlike 1 4-phenylene-bridgd polyvinylsiloxane fluorescence spectra temperature dependence
下载PDF
Preparation and Characterization of Ordered Ladder Like Polyphenylsilsesquioxane via Two-step Sol-gel Method
3
作者 FENG Yu-zhong QI Sheng-li LIU Jing-jing WU Zhan-peng YANG Xiao-ping JIN Ri-guang WU De-zhen 《Chemical Research in Chinese Universities》 SCIE CAS CSCD 2011年第3期516-519,共4页
Soluble and ordered ladder like polyphenylsilsesquioxane was synthesized by a two-step sol-gel method including hydrolysis and polycondensation. The procedure was monitored by Fourier transform infrared spectroscopy a... Soluble and ordered ladder like polyphenylsilsesquioxane was synthesized by a two-step sol-gel method including hydrolysis and polycondensation. The procedure was monitored by Fourier transform infrared spectroscopy and the presence of the ladder like structure was confirmed by X-ray techniques. 29Si NMR analysis shows a very narrow half peak width(δ4) at δ –78.866 of the main chain unit C6H5SiO3/2 of polyphenylsilsesquioxane, indicating that the polyphenylsilsesquioxane has ordered ladder like structures rather than the branched ones. The relationship between molecular weight and the time of polycondensation was also discussed. 展开更多
关键词 Ladder like polyphenylsilsesquioxane Sol-gel preparation X-Ray technique
下载PDF
EFFECT OF POLYMERIZATION CONDITIONS ON THE LADDERLIKE STRUCTURE OF POLYPHENYLSILSESQUIOXANE
4
作者 李桂芝 施良和 叶美玲 《Chinese Journal of Polymer Science》 SCIE CAS CSCD 1996年第1期41-47,共7页
The ladderlike structure of PPSQ synthesized by-using four kinds of catalysts (MgF2, LiF, KOH and DCC) at different polymerization conditions has been investigated by IR and NMR. In the system using MgF2 as the main c... The ladderlike structure of PPSQ synthesized by-using four kinds of catalysts (MgF2, LiF, KOH and DCC) at different polymerization conditions has been investigated by IR and NMR. In the system using MgF2 as the main catalyst, the most important factor which affects the ladderlike structure of PPSQ is the composition of the dual catalysts, MgF2 and DCC. PPSQ prepared by using KOH as the catalyst has the highest regularity of ladderlike structure among all samples. PPSQ with different degree of ladder regularity can be obtained by choice of polymerization conditions. 展开更多
关键词 polyphenylsilsesquioxane STRUCTURE polymerization condition
下载PDF
SYNTHESES OF THE SOLUBLE,HIGH MOLECULAR WEIGHT AND LADDERLIKE POLYPH ENYLSILSESQUIOXAN E AND COPOLYMETHYLPHENYLSILSESQUIOXANES BY PREAMMINOLYSIS METHOD
5
作者 谢祖(王寿) 戴道荣 张榕本 《Chinese Journal of Polymer Science》 SCIE CAS CSCD 1991年第3期266-272,共7页
Soluble, high molecular weight (MW) and ladderlike polyphenylsilsesquioxane (LPPSQ) and its copolymers, ladderlike random and block copolymethyiphenylsilsesquioxanes(LR-PMPSQ and LB-PMPSQ)have been prepared by preammi... Soluble, high molecular weight (MW) and ladderlike polyphenylsilsesquioxane (LPPSQ) and its copolymers, ladderlike random and block copolymethyiphenylsilsesquioxanes(LR-PMPSQ and LB-PMPSQ)have been prepared by preamminolysis, hydrolysis and polycondensation reactions. The preparation method can be carried out easily at the temperature below 95℃ with high yield of 95 %, instead of the conventional way by using high-boiling solvent and any reaction activator or by precipitation with methanol. Three kinds of ladderlike polymers have been characterized. The MW's of the polymers reached to 10~6 without noticeable gelling. The scheme for synthetic route has been proposed. 展开更多
关键词 Ladderlike polymer polyphenylsilsesquioxane and Copolymethylphenylsilsesquioxane
下载PDF
上一页 1 下一页 到第
使用帮助 返回顶部