Influence of natural and accelerated weathering on various formulations of linear low density polyethylene (LLDPE) films

Natural (outdoor) and accelerated (artificial) weathering tests were performed to investigate their influence on thin films (0.1 mm) of linear low density polyethylene (LLDPE). The LLDPE films were prepared of various formulations divided into three batches, with codes A, B and C. A formulation, containing mixture of UVA additives (i.e. Tinuvin 494 FB, Tinuvin NOR 371 and Chimasorb 81), and B formulation contained commercial grade (i.e. Irgastab) light transforming (LT) additive. C formulation contained a combination of UVA and LT additives. An improvement was noticed in the mechanical properties of the UVA batch tested. UVA additives and synergistic mixture with LT showed a better service life and an increase in both yield point of polymer and exposure duration to natural weathering. UVA and LT synergistic mixture (C formulation films) improved time to reach 50% retention of strain by comparison to B formulation films under accelerated and natural weathering. No significant changes were noticed on %transmission measured, but total change in color was improved by UVA additives under natural and accelerated weathering.