Poly(hydroxybutyrate) (PHB)-based films, reinforced with bacterial cellulose (BC) or cellulose nanocrystals (CNC) and plasticized using a molecular (tributyrin) or a polymeric plasticizer (poly(adipate diethylene)), were produced by solvent casting. Their morphological, thermal, wettability, and chemical properties were investigated. Furthermore, the effect of adding both plasticizers (20 wt % respect to the PHB content) and biobased selected nanofillers added at different contents (2 and 4 wt %) on disintegrability in composting conditions was studied. Results of contact angle measurements and calorimetric analysis validated the observed behavior during composting experiments, indicating how CNC aggregation, due to the hydrophilic nature of the filler, slows down the degradation rate but accelerates it in case of increasing content. In contrast, nanocomposites with BC presented an evolution in composting similar to neat PHB, possibly due to the lower hydrophilic character of this material. The addition of the two plasticizers contributed to a better dispersion of the nanoparticles by increasing the interaction between the cellulosic reinforcements and the matrix, whereas the increased crystallinity of the incubated samples in a second stage in composting provoked a reduction in the disintegration rate.

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