Vinyl acetal polymers are terpolymers, with units of vinyl acetate, vinyl alcohol, and vinyl acetal reflecting the three reactions required for their manufacture. Manufacture involves several stages including vinyl acetate polymerization and either sequential or concurrent hydrolysis of poly(vinyl acetate) to poly(vinyl alcohol) and acetalization with an aldehyde in the presence of an acid catalyst. Only poly(vinyl butyral) and to a lesser extent poly(vinyl formal) continue to be made in sizeable commercial quantities. These polymers form hard, unpliable materials that are difficult to process without using solvents or plasticizers. Plasticized poly(vinyl butyral) interlayer for laminated safety glass is by far the largest single application for this class of polymers. Poly(vinyl butyral) provides flexible toughness over a wide range of temperatures and at a lower cost than vinyl acetal polymers derived from longer chain aldehydes. Where stiffer performance at higher temperatures is required, poly(vinyl formal) provides significant property advancement. Applications for vinyl acetal resins make use of their optical clarity, high pigment and filler binding capacity, and excellent adhesion to a variety of surfaces.

SynopsisA high-temperature, high-resolution I3C nuclear magnetic resonance spectroscopy technique was developed for the analysis of poly(p-phenylene sulfide) (HT/HR NMR of PPS). This technique can be applied to the identification and quantitative analysis of end groups and polymer structure in high-temperature polymers where solution temperatures above 2OOOC are required for analysis. Verification of calculated 13C NMR shift values of chloro-terminated and hydrogen-terminated end groups was made by HT/HR NMR of two oligo(p-phenylene sulfide) model compounds.Identification of the chlorine end group was made in high-molecular weight PPS. On the highmolecular weight PPS, identification and quantitative analysis of amino and N-alkylamino end groups were possible only after derivatization of the polymer with I3C-enriched benzoyl chloride.

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