TEMPERATURE DEPENDENCE OF THE FLUORESCENCE SPECTRA OF LADDERLIKE POLYPHENYLSILSESQUIOXANE AND LADDERLIKE 1,4-PHENYLENE-BRIDGED POLYVINYLSILOXANE  

作　　者：张榕本 

机构地区：[1]PCLCC, Center for Molecular Science, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100080 China Polymer Chemistry Laboratory,Chinese Academy of Sciences and China Petro-Chemical Corporation

出　　处：《Chinese Journal of Polymer Science》2002年第1期15-23,共9页高分子科学（英文版）

基　　金：The authors gratefully thank the National Natural Science Foundation of China (No. 29874034, 29992530, 29873060) and Dow Corning Corporation for their financial support.

摘　　要：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.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.

关 键 词：ladderlike polyphenylsilsesquioxane ladderlike 1 4-phenylene-bridgd polyvinylsiloxane fluorescence spectra temperature dependence 

分 类 号：O631[理学—高分子化学]