Study On Sythesis And Analysis Of Polydiph-Enylsiloxane Terminated With Hydrogen

Hydrogen-terminated diphenylsiloxane as the crosslinking agent used in addition-type silicone materials, can improve the refractive index of encapsulation materials in a great extent, it has a great application value. Therefore, Research on synthesis of higher phenyl content crosslinking agent is very significant for synthesis of high refractive index LED encapsulation materials. The research purpose is to synthesis polymerization degree of n=1～4hydrogen-terminated diphenylsiloxane, the main research work and contents are summarized as follows:(1) With diphenylsilanediol as raw materials, conducted self condensation to diphenylsilanediol oligomers intermediates, The experiments investigated the factors that influence the reaction, such as the variety of catalyst, the amount of the catalyst, and reaction time. Through the experiment, we found that under the action of acid catalyst generally got the linear polymer species, while alkaline catalyst usually forming cyclic polymer species. With hydrochloric acid as the catalyst, the mole ratio of Si:HCl=1:0.08, the reaction temperature is25℃, the reaction time is48h, the conversion rate of diphenylsilanediol can reach more than90%.HPLC-MS/MS with electrospray ionization(ESI) in positive mode was used to determine the compounds catalyzed by HCl. The method has the advantage of simplicity, accuracy and sensitivity. Through the optimization of chromatographic conditions, the products were seperated well. On the basis of analysis of the MS and MS2fragmentation information, the products are the mixture of raw material,linear dimeric, trimeric and tetrameric species. Seperately Diphenylsilanediol,1,1,3,3-Tetraphenyl-1,3-disiloxane-diol,1,1,3,3,5,5-Hexaphenyl-1,5-trisiloxanediol,1,1,3,3,5,5,7,7-Octaphenyl-1,7-tetra-siloxanediol. Quantitatively analyze their content by area normalization method, four components contents separately8.55%,70.51%,19.48%,1.46%. Using EI-MS to analyze the products catalyzed by sodium hydroxide,the products mainly the mixture of Hexaphenylcyclotrisiloxane and Octaphenylcyclotetrasiloxane.(2)Hydrogen-terminated polydiphenylsiloxane(HPPS) have been synthesized through the condensation of Diphenylsilanediol Oligomers with1,1,3,3-Tetramethyl-disiloxane (HMM) with hydrochloric acid as the catalyst. The optimum reaction conditions are:the mole ratio of silanol oligomers with HMM is1:8, under25℃, reaction time is3h, the silanol oligomers conversion rate can reach more than99%.The reaction products were characterized by IR,NMR,HPLC-ESI-MS/MS,HPLC-APCI-M8/MS,MALDI-TOF-MS. The products contained eight kinds of components, mainly the mixture of single hydrogen-terminated and double hydrogen-terminated species.Combined mass spectrometry with secondary mass spectrometry information, studied the MS fragmentation mechanism of the diphenylsilanediol oligomers and Hydrogen-terminated polydiphenylsiloxane, and gave a rational explanation to the result, This research provides certain reference for the mass spectrometry analysis of this compounds.The originality in this thesis:This thesis use the diphenylsilanediol oligomers intermediates to synthesize high refractive index crosslinking agent of encapsulation materials, with tetrahydrofuran as the solvent system to synthesis polymerization degree of n=1-4Hydrogen-terminate-d polydiphenylsiloxane. This method includes two steps to complete, it is more easy to control than the traditional organosilane hydrolysis polycondensation. Using HPLC-MS/MS technology to separate and analyze the intermediate products and Hydrogen-terminated polydiphenylsiloxane, The method has the advantage of simplicity, accura-cy and sensitivity.