Fully Biodegradable Films Based on Functionalized Natural Polyphenol/Poly(3-Hydroxybutyrate-co-3-Hydroxyvalerate) as a Potential Material for Food Packaging

Abstract

As a potential material for food packaging, fully biodegradable composite films based on novel functionalized natural polyphenol/Poly (3-hydroxybutyrate- co -3-hydroxyvalerate) (PHBV) were successfully fabricated by solution casting, and also the functionalized natural polyphenol (C 18 TA x ) was synthesized by grafting fatty acid onto natural polyphenol Tannic Acid (TA). The resultant C 18 TA x with better hydrophobicity was uniformly dispersed into a PHBV matrix. The influence of C 18 TA x dosage on the mechanical behavior, crystallization behavior and thermal properties of the C 18 TA x /PHBV composite films was investigated by uniaxial tensile mechanical testing, Differential Scanning Calorimeter (DSC), Polarizing Optical Microscope (POM) and Wide Angle X-ray Diffractometry (WAXD). The results revealed that the x value was about 0.09, showing that about 11/20 phenol hydroxy groups in TA molecules were replaced with fatty acid chains. Compared with those of neat PHBV, the tensile strength and elongation at break of the C 18 TA 0.09 /PHBV composite films with 10 wt.% C 18 TA 0.09 content were enhanced by 121%, and 458%, respectively. This improvement was primarily ascribed to intermolecular hydrogen bonding interactions in composite films. This new type of fully biodegradable bio-based composite films shows great potential for food packaging.