Development and characterization of high environmental performance composites of Bio-PBSA and short hemp fibers from different compatibilization strategies

Abstract

In this research work, the effect of various compatibilizing agents on naturally sourced composites formed from poly(butylene succinate-co-adipate) - PBSA and short hemp fibers has been analyzed. Hemp has been employed as a natural reinforcement to obtain environmentally friendly composites, using biobased PBSA as a matrix. These composites were obtained from twin-screw extrusion and shaped by injection molding. To improve the poor compatibility between the matrix and lignocellulosic fibers, different compatibilizing agents were used, including a maleic anhydride graft copolymer (PBSA-g-MA), a copolymer based on itaconic acid (PBSA-g-IA) and dibutyl itaconate (DBI). The addition of these compatibilizers provided different levels of improvement with respect to the PBSA/hemp base compound. In relation to the mechanical properties, the addition of the copolymers significantly increased the maximum tensile stress, with values around 20 MPa, with respect to the 8,86 MPa of the PBSA/hemp uncompatibilized composite. The addition of DBI to the base blend led to an improvement in the elongation at break of 82% (3,51% elongation at break of the base blend versus 6,40% with the addition of DBI).  These results are in agreement with those obtained in dynamic mechanical thermal analysis (DMTA), where the incorporation of hemp fibers and the combination of the different compatibilizers resulted in an improvement in stiffness over the entire temperature range.