Polymer bound HALS - expectations and possibilities

This study confronts the traditional opinion on the physical aspects of the HALS efficiency with the available experimental reality. The results indicate that the generally accepted importance of additive migration may need to be reconsidered. Based on the experimental evidence, three empirical requirements for an effective stabiliser are formulated: high solubility, minimal diffusion and high homogeneity of distribution of active species. Chemical grafting of a low molecular stabiliser is suggested to meet the defined empirical requirements. The results achieved with polymer bound HALS (PBH) prepared by reactive processing technology confirm the expectations. The stabilisation efficiency of PBH significantly outperforms the conventional low molecular and oligomeric stabilisers. (C) 1998 Elsevier Science Limited. All rights reserved.