Development of PBS/Nano Composite PHB-Based Multilayer Blown Films with Enhanced Properties for Food Packaging Applications

Abstract

Biobased and biodegradable plastics have emerged as promising alternatives to conventional plastics offering the potential to reduce environmental impacts while promoting sustainability. This study focuses on the production of multilayer blown films with enhanced functional properties suitable for food packaging applications. Films were developed through co-extrusion in a three-layer film configuration, with Polybutylene Succinate (PBS) and Polybutylene Succinate Adipate (PBSA) as the external and internal layers, respectively. The functional layer consisted of Polyhydroxybutyrate (PHB) enhanced with nanoclays Cloisite® 30B at varying weight ratios. Films were also processed by manipulating the extruder screw speed of the functional layer to investigate its impact on the functional properties. Rheology, mechanical strength, and barrier performance were characterised to establish correlations between processing conditions and functional layer blends (Cloisite® 30B/PHB) on the properties of the resultant films. Rheological test results indicated that the system with 5% Cloisite® had the best polymer/nanofiller matrix dispersion. Mechanical and permeability tests showed that by varying the process conditions (the alteration of the thickness of the functionalized layer) resulted in an improvement in mechanical and barrier properties. Furthermore, the addition of the nanofiller resulted in a stiffening of the film with a subsequent decrease in permeability to oxygen and water vapour.