EFFECT OF CHEMICAL-STRUCTURE AND CRYSTALLINITY ON SORPTION, DIFFUSION AND CHEMICAL-STABILITY OF POLYURETHANEACETALS

The diffusion of water in non-isocyanate polyurethaneacetals (PUA) of various kinds and compositions has been studied. The direct relationship between the composition of polymers, their degree of crystallinity, morphology and diffusional characteristics has been demonstrated. It has been shown that by changing the polymer composition one can obtain hydrated polymer systems of every type, hydrophobic, hydrophilic and moderately hydrophilic. The kinetics of hydrolytic degradation of PUA in HCl solutions (pH equals 0. 1) between 20 and 75 degree C has been investigated. Hydrolysis of acetal bonds has been found to occur in the amorphous phase of a polymer sample, which is mostly formed by the fragments of urethane glycol. The influence of morphology on PUA diffusional characteristics and their stability to hydrolysis has been determined. It has been shown that the physico-chemical properties of PUA can be regulated without the introduction of new compounds.