Environmental degradation of peroxide modified poly(L-lactide)

Poly(L-lactide) (PLLA), prepared by a tin(II)-octoate initiated ring-opening melt-polymerization was separately modified with tert-butylperoxy benzoate (0.1, 0.25 and 0.5 wt%) in an extruder. The peroxide modification retarded the melt degradation and caused changes in the morphology of the polymer. Injection molded specimens of unmodified and peroxide modified PLLA were prepared. Changes in weight, mechanical strength, molar mass and in the morphology were studied during degradation in soil. The peroxide modified samples underwent a more rapid degradation than the unmodified ones, which can be related to the morphological changes caused by the peroxide modification. The degradation behavior could mainly be related to accessibility to water.