ABSTRACT
To be effective photodegradants, cerium compounds need to be used at specific concentrations in commodity thermoplastics. For routine use in industry, additives need to be stable enough to be compounded into the polymer during the processing when the resin is in a melt stage. If the process is rapid enough, the plastic film upon exposure outdoors disintegrates, being separated into fragments to small to be distinguishable from background soil and is dispersed by the wind. If the cumulative solar radiation is a linear function of the exposure time, it is reasonable and convenient to interpret the data in terms of days or weeks of exposure. Gel permeation chromatography was performed in order to quantitate the loss of physical properties as a decrease in weight average and number average molecular weight as a function of exposure time. A more accurate means of establishing degradation of a plastic film is by measurement of the tensile properties of the exposed test piece.
