Mechanical behaviour above T-g of a plasticised PVC reinforced with cellulose whiskers; a SANS structural study

In previous works, the processing of nanocomposites of cellulose whisker fi lled thermoplastics was presented as well as their mechanical behaviour in the glassy state, both in the linear and non-linear domains. The purpose of the present work is to evaluate the mechanical properties of these composi tes in the rubbery state. A simple modelling of the mechanical behaviour, u sing the classical entropy elasticity theory, is proposed and discussed. Pa rticular attention was paid to damage phenomena, already observed with stre tched composite in the glassy state. Damage is mainly explained as a debond ing of the matrix at the whisker interface. Small-Angle Neutron Scattering experiments performed on stretched composites provide supplementary informa tion on the matrix microstructure with and without whiskers, and on the evo lution of this microstructure with the sample deformation. Results confirm the heterogeneous characteristic of the matrix. Void scattering is identifi ed and interpreted. (C) 1999 Elsevier Science Ltd. All rights reserved.