Opposing effects of nanoclay on viscoelastic response of reactive phenoxy/poly (trimethylene terephthalate) blends: Clay‐induced transreactions versus percolated network formation

Abstract The role of nanofillers in reactive blends, which are compatibilized via interchange/exchange reactions, in particular transesterification reactions, is still a challenge. In this study, effects of clay on viscoelastic response of reactive melt intercalated phenoxy/poly (trimethylene terephthalate) blends are investigated. Using rheological plots, it was found that at low clay contents, clay‐induced transreactions could cause an unexpectedly enhanced viscous response. But higher clay contents lead to an enhancement in elastic behavior by inducing the formation of a percolated network. The observed opposing effects of clay particles on viscoelastic response were further examined by stress relaxation analysis, which verified the enhanced viscous response at low clay contents. The effect of interaction between the silicate layers and the blend matrix is also probed by using two different organo‐modifiers. Viscoelastic behavior of samples was also studied by dynamic mechanical analysis, and the results corroborated our findings from rheological measurements. Based on loss modulus data, the improved dynamic homogeneity of nanocomposites is attributed to the enhanced transreactions and stronger hydrogen bonds between the blend components. POLYM. COMPOS., 2011. © 2010 Society of Plastics Engineers