Effects of tributyrin as plasticizer in poly(3-hydroxybutyrate-co-3-hydroxyvalerate) on processability, mechanical, and thermal properties

The development of biodegradable polymers has been stimulated owing to the inappropriate litter disposing in order to replace conventional polymers with long-time degradation. As their performance is a challenge to this replacement, the insertion of additives in biodegradable polymers such as poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV) consists in an effective way of adjusting their properties. For this reason, it was analyzed the incorporation of tributyrin (TB) in the matrix of PHBV as a plasticizer, so that higher plastic deformation is achieved. Samples of neat PHBV and with plasticizer concentrations of 5, 10, and 15 wt% were prepared by double screw extruder followed by press molding under temperature. Plasticizer exudation test confirmed the presence of TB in the samples of PHBV. Mechanical test showed the highest value of tensile strength and elongation at break for PHBV/5TB, with 23.4 MPa and 2.84%, respectively. It was observed at differential scanning calorimetry and dynamic mechanical thermal analysis that the PHBV/5TB resulted in an increase of 3% on crystallinity, a decrease of 3% on melting temperature, and a decrease of 46% and 29% on glass transition temperature by E'' and tan d curves, respectively, compared with neat PHBV. Thus, PHBV/5TB was determined as the most appropriate composition for enhancing processability and properties of PHBV.