Studies on enhanced degradable plastics. II. Weathering of enhanced photodegradable polyethylenes under marine and freshwater floating exposure

The weatherability of three types of enhanced photodegradable polyethylene films and corresponding control films were studied under outdoor and marine floating conditions at two exposure sites. Progress of weathering was monitored using tensile elongation at break. In general, both the enhanced-degradable plastics and the corresponding controls degraded slower in marine exposure than in outdoor exposure. This is attributed to the lower sample temperatures (compared to samples exposed outdoors) and to shielding from light afforded by surface fouling in samples exposed floating in sea water. Enhanced-photodegradable polyethylenes disintegrated faster than the control samples in the case of both outdoor and marine exposures. The improvement obtained in marine exposures was greater than that for outdoor exposure of corresponding sample types. This is due to the extremely slow rates of disintegration of control films under marine floating conditions.