Mechanical behavior during different weathering tests of the polyurethane elastomers films

Segmented poly(ester–urethane)elastomers (PU) based on poly(ethylene diethylene adipate) diols as a soft segment and aromatic diisocyanates in the hard segment were synthesized by a conventional method. The precipitated and compact polyurethane films have been degraded after a limited exposure to natural weathering. The effects on mechanical properties of precipitated and compact polyurethane films were found to be a measure of the degradation due to weathering. The present study attempts to correlate the physical–mechanical properties of the precipitated polyurethane and compact films with time of weathering. In all cases a certain amount of oxidative change had been initiated. This was probably associated with enzyme adsorption on surfaces. We compared natural weathering of PU films carried out in earth, seawater and exposure to sunlight with untreated samples. In common with other weathering tests, the effect was to decrease the ultimate tensile strain, except seawater. It was found that enzymatic degradation in the earth occurred only after, the ageing process was continuous and practically linear with a relatively short initial period of increase in degradation rate.