Développement de polymères et composites alvéolaires bio-sourcés à base de poly(acide lactique)

Jean Mario Julien 1
1 Pôle MPA
C2MA - Centre des Matériaux des Mines d'Alès
Abstract : The use of polymers derived from renewable resources and the replacement of massive parts by cellular products constitute interesting approaches in the current context of sustainable development. This study therefore focuses on the development of bio-sourced cellular polymers and composites based on polylactic acid (PLA) and cellulose fibers obtained by extrusion foaming in presence of an endothermic chemical foaming agent (CFA). Single-screw extrusion foaming conditions have been optimized according to density reduction. An optimal processing parameters set (temperature profile, screw rotation speed, cooling conditions) led to a void fraction of 47 % with an open-cells ratio in the 10-26 % range. The type of PLA as well as the type and weight fraction of CFA have significant influence on the cells size and density and on the final mechanical properties. Moreover PLA have been modified through g-ray irradiation (with different irradiation doses and various contents of crosslinking agent TAIC) and through the incorporation of different contents of an epoxy based chain-extender. No increase in the void fraction was obtained (maximum of 44 %) but a significant effect on the cell size (-39 %), the cell density (+60 %) and the mechanical properties were observed. The incorporation of different contents of cellulose fibers with various shape factors (short fibers and microfibers) did not improve the void fraction (10-25 %) but had an influence on the cells size (-48 %) and the open-cells ratio (26- 38 %). The surface treatment of cellulose fibers by an aminosilane did not modify any properties.
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Jean Mario Julien. Développement de polymères et composites alvéolaires bio-sourcés à base de poly(acide lactique). Matériaux. Université de Lille 1, 2011. Français. ⟨tel-00726158⟩

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