Synthesis And Structural Characterization Of Polyvinyl Butyral

Polyvinyl butyral(PVB) is an ideal material for the production of la minated safety glass film middle layer, which presents good flexibility, cohesiveness, transparency and high impact-resistance. In recent years, with the rapid development of the automobile and construction industry, the development of PVB resin possesses unprecedented opportunities. PVB resins are produced domestically by two steps precipitation, but this production process always exist the caking problem. To solve this problem, almost all the manufacturers use various emulsifiers to disperse PVB, which bring the difficulty of removing emulsifiers. By changing the synthesis conditions, powdered PVB resin was obtained without any emulsifier and organic solvent in this thesis. The powdered PVB resin could be synthesized by the following steps. Quantitative PVA was dissolved firstly in water at 90℃, and the catalyst(hydrochloric acid) was added to the solution,the mixture was cooled to room temperature and the butyraldehyde was dropped in the mixture with the speed of 20-30 drops per minute. The reaction mixture was kept for 1.0h. The temperature was raised to 60℃ and the reaction mixture was kept for 1.0h. In addition, the dropping speed of butylaldehyde, stirring speed and other factors will affect the quality of PVB resin.The results showed that a powdered PVB resin was obtained when PVA concentration in water, the weight of HC l and butyraldehyde(all based on the weight of PVA) were 12%, 5.5%, 61.3%, respectively. The content of acetal group of the PVB resin was 83%.The appropriate analysis method for determining the content of acetal group in PVB was established. The hydroxylamine hydrochloride-triethanolamine method to determine the content of acetal group of PVB, the standard deviation is only 0.74%. The reaction condition in the method was researched and the appropriate reflux time was 1.0 h.The structure of the PVB was characterized by infrared spectroscopy(FT-IR) and nuclear magnetic resonance(1H-NMR). The PVB obtained in the thesis was close to commercial PVB resin in molecular weight and viscosity, which meet the industrial standard.