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Efeitos do extensor de cadeia na morfologia, propriedades reológicas e mecânicas de filme tubular de blendas de poli(ácido) láctico) PLA com poli(butileno-adipato-co-tereftlalato) PBAT

Year: 2015
Type: dissertation
Abstract: This study investigated the effect of chain extender epoxy based additive, Joncryl ADR 4368, on the rheological, thermal and mechanical properties of poly(lactic acid) with poly(butylene adipate-co-terephthalate) (PLA/PBAT) blends in the blown films form. Compositions with 40% and 60% by weight PLA were selected for production of such blown films. These dispersed phase content was chosen because the literature does not present mechanical behavior studies of tubular film blends with high concentration of the dispersed phase. Rheological analysis in dynamic oscillatory regime showed the reaction of epoxy group with end chain in both polymers, and a higher reactivity of the chain extender with PLA. The films produced exhibited different morphologies according to the blend composition and chain extender content. Films containing 40% PLA presented the dispersed phase morphology in a fibrillar form; however in the presence of chain extender, the dispersed phase is presented as ellipsoids. This change in morphology resulted in a reduction in the mechanical properties of these films in tensile tests. Films containing 60% PLA had a coarse morphology with dispersed phase in the ribbons-like form. The addition of extender yielded a refinement of the dispersed phase morphology from ribbon to elongated fibril form, which is responsible for the mechanical properties improvement of these films. Despite the low adhesion between matrix and dispersed phase, the proper setting of the morphology of the blends as a function of additive content, allowed to produce films with mechanical properties quite different from each other.
Language: Portuguese
Open Access status: green
OpenAlex ID: W2725594178
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