Structurally bound stabilizers: Melt grafting of UV stabilizers onto polypropylene, polyethylene, and polystyrene

Monomeric ultraviolet stabilizers, 2‐hydroxy‐4‐methacryloyloxy benzophenone and 2‐hydroxy‐4‐acryloyloxy benzophenone were synthesized by a modified process. These reactive UV stabilizers were grafted onto the backbone of polypropylene (PP), low‐density polyethylene (LDPE), and polystyrene (PS) by melt processing in the mixer of Brabender Plasticorder. An infrared spectroscopic method was standardized for the quantitative determination of the extent grafting of these additives on the polymer backbone. Grafting of both the additives occurred in the order PS > LDPE > PP. Methacryloxy derivative of benzophenone was found to be more reactive towards the polymers studied than the acryloxy derivative.