Properties and Processing Relationship of Polyhydroxybutyrate and Cellulose Biocomposites

Abstract The aim of this work was the development of totally biodegradable composites for using as packaging in food and agriculture industry. Optimum conditions to obtain bilayer composites from polyhydroxybutyrate (PHB) and cellulose cardboard by solvent casting and compression molding were found. The composites obtained by casting showed lower moisture absorption than the ones made by compression molding, due to the penetration of PHB solution (hydrophobic) into the fibers of cellulose cardboard (hydrophilic). However, pressed materials showed better mechanical and permeation properties than the composites obtained by casting, because PHB formed a continuous layer on cellulose cardboard. Mechanical and barrier properties of the composites were optimized, using the least amount of PHB, due to its high cost. The optimum amount of PHB determined was 10 wt% for composites made by casting and 15 wt% for pressed composites.