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Publicação
Study of the degradation mechanisms of polyethylene during reprocessing
Orientador(es)
Resumo(s)
The present work aims at evaluating the behaviour of various grades of high and low density polyethylene subjected to continuous injection moulding operations. It is based on a wide range of experimental techniques that allowed the establishment of relationships between the observed property changes and the structural modifications developed in the polymers. The study confirmed the coexistence of two distinct degradation mechanisms, crosslinking and chain scission, that occur due to thermo-oxidative reactions arising during the different injection moulding stages. The relative importance of these two mechanisms depends on the material structure and on the processing conditions used. It was also possible to confirm that the polyethylenes with lower molecular mass show low sensitivity to degradation during reprocessing. Furthermore, the more branched polymers (as is the case of LDPE) also proved to be less sensitive to thermo-degradation phenomena. Overall, it was concluded that the primary recycling of polyethylene, if performed under well controlled conditions, will lead to only minor material property losses.
Descrição
Palavras-chave
Plastics waste Primary recycling Reprocessing Polyethylene Degradation mechanisms Processing-structure–properties relationships
Contexto Educativo
Citação
A.A. Mendes, A.M. Cunha, C.A. Bernardo, Study of the degradation mechanisms of polyethylene during reprocessing, Polymer Degradation and Stability, Volume 96, Issue 6, 2011, Pages 1125-1133, ISSN 0141-3910, https://doi.org/10.1016/j.polymdegradstab.2011.02.015.
Editora
Elsevier BV