Part I. Synthesis of organosilane fire retardants. Part II. Characterization of roadway asphalts by high-performance gel permeation chromatography.

摘要

art I. Synthesis of organosilane fire retardants. In Part I of this research, several organosilicon compounds which could be used as a nonleaching chain-stopping fire retardant have been synthesized. A series of bromination/dehydrobromination/bromination reactions have been performed to prepare brominated organo(alkoxy)silanes. 1,2-Dibromoethyl(alkoxy)silanes were prepared by the addition of bromine to vinyl(alkoxy)silanes at 0;Part II. Characterization of roadway asphalts by high performance gel permeation chromatography. In this study, high performance gel permeation chromatography (HP-GPC) is used to predict the performance of the roadway asphalt binders and to monitor the changes in the asphalt binders that result from the aging of the pavement. The molecular size distribution (MSD) profiles for asphalts describe the chemical constitution of asphalt by referring to the percentages of the large molecular size (LMS), medium molecular size (MMS), and small molecular size (SMS) particles. These HP-GPC parameters are used as predictors to evaluate the asphalt pavement performance. Roadway aging can be followed by monitoring changes in the LMS, MMS, and SMS particles. The analysis of these parameters during the aging process can predict the quality of the roadway binders and can be used to describe the gross chemical changes in the asphaltic binders.;In this effort, thirty-two roadway projects which were constructed between February 1983 and August 1987 have been observed for condition followed by HP-GPC study for up to 84 months.;Di(ethylthio)ethyl(alkoxy)silanes were prepared by reactions of 1,2-dibromoethyl(trimethoxy)silane and 1,2-dibromoethyl(methyl)diethoxysilane with an excess of sodium ethanethiolate in petroleum ether. The reactions proceed by displacement of the bromine atoms present in the molecules forming 1,2-di(ethylthio)ethyl(trimethoxy)silane and 1,2-di(ethylthio)ethyl(methyl)diethoxysilane. The reactions with NaSEt were complicated by the competition between elimination and nucleophilic attack at the carbon atoms of the ethyl group. The products were characterized by GC-Mass spectrometry, as well as by infrared,