COMPARISON OF THE THERMAL AND LIGHT STABILIZING ACTION OF NOVEL IMINEAND PIPERAZINE BASED HINDERED PIPERIDINE STABILIZERS IN POLYOLEFINS

A novel imine stabiliser based on 2-hydroxybenzophenone and a 4-amino- tetramethylpiperidine structure has been synthesised and characterised , as have two novel mono and bis-alkylated esters of tetramethylpiperi dine with piperazine. Using FTIR spectroscopy, rates of polymer oxidat ion were measured by carbonyl index. Hydroperoxide formation was also measured. All three structures are shown to be highly effective therma l and light stabilisers for polyethylene and polypropylene. In all cas es their thermal and light stabilising activities are consistent and f ollow their ability to inhibit hydroperoxide formation during thermal aging. The ability of the stabilisers to operate as effective radical scavengers is discussed and related to the effects of some commercial thermal and light stabilisers.