Structural Differences Between Similar Commercial Grades of Polyvinyl Alcohol‐Acetate

Abstract The properties of ostensibly similar grades of polyvinyl alcohol‐acetate are often found to be drastically different: for example, the viscosity of a polyvinyl acetate latex prepared using polyvinyl alcohol in the emulsifier system was reduced by half when a different sample of polyvinyl alcohol was used, yet the polyvinyl alcohols appeared to be identical in most respects. However, when the { 1 H } −13C n.m.r. spectra were obtained under identical conditions it was found that the ratio of the intensities of the methine and methylene resonances differed. This is attributable to a difference in the extent of short‐chain non‐hydrolysable branching.