Green Composites from Partially Bio-Based Poly(butylene succinate-co-adipate)-PBSA and Short Hemp Fibers with Itaconic Acid-Derived Compatibilizers and Plasticizers

Abstract

[EN] In this work, green composites have been developed and characterized using a bio-based poly-meric matrix such as BioPBSA and the introduction of a 30 wt.% short hemp fibers as a natural reinforcement to obtain materials with maximum environmental efficiency. In order to increase the interfacial adhesion between the matrix and the fiber to obtain better properties in the com-posites, a reactive extrusion process have been carried out. On the one hand, different additives derived from bio-based itaconic acid have been added to the BioPBSA/HEMP composite, such as Dibutyl itaconate (DBI) and a copolymer of PBSA grafted with itaconic acid (PBSA-g-IA). On the other hand, a different copolymer of PBSA grafted with maleic anhydride (PBSA-g-MA) was also tested. The resulting composites have been processed by injection-molding to obtain different samples which were evaluated in terms of mechanical, thermal, chemical, dynamic-mechanical, morphological and wettability and color properties. In relation to the mechanical properties, the incorporation of hemp fibers has resulted in an increase in the stiffness of the base polymer. The tensile modulus of pure BioPBSA has increased from 281 MPa to 3482 MPa with 30% fiber. The addition of DBI shows a remarkable improvement in the ductility of the composites, while co-polymers with IA and MA, generate mechanically balanced composites. In terms of thermal properties, the incorporation of hemp fibre and compatibilising agents leads to a reduction in thermal stability. However, from the point of view of thermomechanical properties, a clear in-crease in rigidity is achieved throughout the temperature range studied. As far as the colour of the samples is concerned, the incorporation of hemp generates a typical colour, while the incorpora-tion of the compatibilising agents does not modify this colour excessively. Finally, the introduc-tion of lignocellulosic fibers greatly affects water absorption and contact angle, although the use of additives helped to mitigate this effect.