Prodegradant additives effect onto comercial polyolefins

Abstract

Prodegradant additives (PDA) came up in the last few decades as a possible solution to the low degradability of polyolefins. PDAs attack polyolefins chains cutting and degrading them to a degree that eventually may allow phagocytosis by microorganisms. Also, considering that the PDA is added in very low quantities, main additives suppliers affirm that a priori they neither alter mechanical properties nor the recyclability of the polymer. In order to verify these claims, this work comprehends a systematic study to analyze the effectiveness of some commercially available PDAs on different polyolefins. Diverse degradability analysis of LDPE, HDPE and PP additivated with 1 and 2 wt% of PDA were performed comparing changes on molecular weights, rheological and mechanical properties among them and base polyolefins, all under two kinds of experiments: natural and UV accelerated aging. It was found that the addition of PDA accelerates degradation since after both aging processes samples with PDA were significantly more degraded than base polyolefins under same conditions. Moreover, processing also contributes to the degradation process, being more noticeable in PP. However, results demonstrate that chain scission of polyolefins additivated with PDA is not being improved to an extent that would allow biodegradation.