Studies on the viscoelasticity of poly(trimethylene terephthalate)/poly(ethylene-octene)/organomontmorillonite nanocomposites

The viscoelasticity of poly(trimethylene terephthalate)/maleinized poly(octene-ethylene) copolymer/organomontmorillonite (OMMT) nanocomposites were investigated at both liquid and glassy states by using the rotational rheometer and dynamic mechanical analysis, respectively. The viscoelasticity results suggest that OMMT has many important influences on the structure, modulus, toughness, and cold-crystallization of the nanocomposites. The OMMT has a strip-like sheet morphology in the polymer matrix and when OMMT content increases to 4 wt%, the physical network-like structure begins to form in the nanocomposites. The pseudoplasticity of the melts is increased by OMMT. In addition, the complex viscosity, storage modulus, and viscous behavior of the melts are increased with increasing OMMT content. The creep resistance of the nanocomposites is improved by OMMT, and it plays an important role on reinforcing the melts. The stress relaxation of the melts suggests that the nanofillers can not only enhance the interfacial interactions of the nanocomposites but also inhibit the recovery of the polymer chain segments. At glassy state, the nanocomposites' storage modulus increases with increasing OMMT content. As glass transition occurs, the loss factor and loss modulus suggest that OMMT toughens the polymer matrix. At rubber-elastic state, OMMT depresses the cold-crystallization of the polymer matrix due to its limitation effect on the motion of molecular chains. POLYM. COMPOS., 2012. (C) 2012 Society of Plastics Engineers