Simultaneous plasticization and blending of isolated soy protein with poly(butylene succinate-co-adipate)
Résumé
Agrarian proteins, due to their good film forming properties, moderate cost, and biodegradable nature, have been extensively studied to develop affordable packaging materials. However, when compared to conventional polymers, isolated proteins based polymers have poor mechanical and barrier properties. Blending with others polymers seems to be a viable option to overcome these issues. The present work focuses on the preparation of isolated soy protein (ISP) / poly[(butylene succinate)-coadipate] (PBSA) blends with different ratios by extrusion and injection moulding using glycerol and water mixture as plasticizer. PBSA is bio-based, biodegradable, and its relatively low melting point is compatible with the processing temperature of ISP. Two different processing strategies were used and compared for the preparation of blends. In the novel single step approach, ISP, plasticizers (glycerol and water) and PBSA are dry mixed and extruded all together in a co-rotating twin-screw extruder. In the regular two-step approach, plasticized protein is prepared by extrusion of ISP with a glycerol/water mixture, followed by a second extrusion step of plasticized protein with PBSA. Prepared blends were characterized for their morphology, thermal, dynamic mechanical and mechanical properties. The mechanical properties of the blends prepared by single step process are roughly similar to those produced by two-step process; this indicates the efficiency of one-step melt processing of PBSA with isolated soy protein involving plasticization, denaturation, melt-melt mixing and morphology development in the extruder, this compounding method being moreover less time consuming.
Origine : Fichiers produits par l'(les) auteur(s)
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