Cellulose whiskers reinforced polyvinyl alcohol copolymers nanocomposites

Nanocomposite materials were prepared from copolymers of polyvinyl alcohol and polyvinyl acetate and a colloidal aqueous suspension of cellulose whiskers prepared from cotton linter. The degree of hydrolysis of the matrix was varied in order to vary the hydrophilic character of the polymer matrix and then the degree of interaction between the filler and the matrix. Nanocomposite films were conditioned at various moisture contents, and the dynamic mechanical and thermal properties were characterized using dynamic mechanical analysis and differential scanning calorimetry, respectively. Tensile tests were performed at room temperature to estimate mechanical properties of the films in the non linear range. All the results show that stronger filler/matrix interactions occur for fully hydrolyzed PVA compared to partially hydrolyzed samples. For moist samples, a water accumulation at the interface was evidenced. The reinforcing effect was found to be all the higher as the degree of hydrolysis of the matrix was high.