Effect of water absorption on the plastic deformation behavior of nylon 6

The tensile behavior of nylon 6 films has been investigated in relation to water content. Modification of chain mobility in the amorphous phase via water plasticization appears to have a determining impact on the stress-strain response. More specifically, both yield stress value and hardening behavior over a large strain domain are strikingly equivalent for samples drawn at same ΔT between draw temperature T_d and main amorphous relaxation temperature T_α. This apparent lack of thermal activation of crystal plasticity in the fibrillar transformation suggests that crystal block fragmentation proceeds via H-bond unzipping through water penetration at defective crystal interfaces.