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Unusual extensional behavior of a polystyrene/HIPS blend

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Resumo:The present work focuses on the study of the rheological behavior in extension of three different polystyrene melts (a general-purpose polystyrene, GPPS, a high-impact polystyrene, HIPS, and a 50/50 blend of both), in particular the behavior at failure and at rupture in extension that are (ultimately) related with the materials' ability to endure the various stages of extension-dominated processing sequences such as thermoforming. The aim is to try to explore possible synergistic effects arising in extension-dominated flows by means of physically blending the two base materials. The rheological characterization was performed in terms of both the linear and non-linear viscoelastic behavior, in shear and extensional flows. The results show that blending the two materials has important consequences on the extensional behavior, the blend showing a higher degree of extension-thickening than either GPPS or HIPS and that there is indeed a synergistic effect in what regards the rupture and failure behavior.
Autores principais:Barroso, Vitor C.
Outros Autores:Ribeiro, Sandra P.; Maia, João Manuel Luís Lopes
Assunto:polystyrene blends uniaxial extension stress relaxation
Ano:2003
País:Portugal
Tipo de documento:artigo
Tipo de acesso:acesso restrito
Instituição associada:Universidade do Minho
Idioma:inglês
Origem:RepositóriUM - Universidade do Minho
Descrição
Resumo:The present work focuses on the study of the rheological behavior in extension of three different polystyrene melts (a general-purpose polystyrene, GPPS, a high-impact polystyrene, HIPS, and a 50/50 blend of both), in particular the behavior at failure and at rupture in extension that are (ultimately) related with the materials' ability to endure the various stages of extension-dominated processing sequences such as thermoforming. The aim is to try to explore possible synergistic effects arising in extension-dominated flows by means of physically blending the two base materials. The rheological characterization was performed in terms of both the linear and non-linear viscoelastic behavior, in shear and extensional flows. The results show that blending the two materials has important consequences on the extensional behavior, the blend showing a higher degree of extension-thickening than either GPPS or HIPS and that there is indeed a synergistic effect in what regards the rupture and failure behavior.