Effect of Water Sorption on the Flexural Properties of a Fully Biodegradable Composite

Abstract
The water absorption process of the short-time process of a fully biodegradable composite is important in order to know the effect of water uptake on the mechanical properties before the polymer is hydrolysed. The matrix of the studied composites is a commercial blend based on starch and cellulose derivatives, named MaterBi-Y. The effect of the fibre content was also taken into account, because short sisal fibres’ content was changed from 5 to 15 wt%. Diffusion coefficients, the equilibrium water uptake and the flexural properties were determined during sorption experiments at different bath temperatures: 5, 25 and 60 C. Equations obtained from microscopic mass balances for diffusion in solids were used to model the water absorption of these composites as a function of immersion time.