Synergism Effect of Montmorillonite and Cellulose Whiskers on the Mechanical and Barrier Properties of Natural Rubber Composites
Résumé
A series of nanocomposite films based on natural rubber (NR), Na(+)-montmorillonite (MMT), and cellulose whiskers (W) was prepared, keeping a total filler content equal to 5wt.-%. In the binary NR/MMT system, small stacks of intercalated montmorillonites were homogeneously dispersed within the polymermatrix whereas they were clearly lying in the vicinity of cellulose whiskers in the ternary NR/MMT/W blends. The effects of MMT and W on mechanical and gas barrier properties of the nanocomposite films were investigated. A significant increase of the rubbery modulus was obtained upon filler addition. The reinforcing effect was particularly important for the nanocomposite film reinforced with 1 wt.-% MMT and 4wt.-% W. The improvement of the gas barrier properties observed upon filler addition was explained by a tortuosity effect. The calculated tortuosity values indicated that the simultaneous use of MMT and W could greatly slow down the gas diffusion rate in NR. Formation of MMT-W sub-assembly should be responsible for this synergism effect.