Preparation of poly(vinyl butyral) by precipitation method and its characterization

Poly(vinyl butyral) (PVB) was synthesized by acetalization of poly(vinyl alcohol) (PVA). PVB was prepared in particulate forms in water, and chemical and physical properties of the products were characterized using various techniques. The prepared PVB had size distribution from 100 to 700 μm with mean diameter of about 380 μm. The chemical structure of PVB was characterized using FT/IR and NMR, and the average degree of acetalization was determined to be 77% from the titration measurement. DSC data showed that the crystalline structure of PVA vanished as acetalization reaction proceeded to produce PVB, and the glass transition temperature emerged at about 70°C. TGA data showed that PVB was much more thermally stable than PVA, and showed no degradation up to 300°C. Solubility test showed that PVB was soluble in alcohols but insoluble in water, being totally different from PVA.