Relation of composition of polyvinyl acetals to their physical properties. I. Acetals of saturated aliphatic aldehydes

Polyvinyl alcohol was condensed with straight and branched chain aldehydes (CnH2nO, n = 2 to 8) to varying degrees of completion. Measurements on resins and plasticized compositions included apparent modulus of elasticity at various temperatures, brittle temperature, tensile strength and elongation, and solubility. From these measurements it is concluded that: (1) Increasing degree of acetalization results in lowered transition temperature, lower stiffness at transition, narrower transition range, higher brittle temperature, decreased tensile strength, and shift in solubility toward solvents of lower dielectric constant. (2) Acetals of higher normal aldehydes have lower transition and brittle temperatures, lower tensile strength, and more limited solubility. (3) Branched chain aldehydes have higher transition and brittle temperatures than their normal isomers.