Non-isothermal and isothermal crystallization of nanocomposites based on functionalized polyethylenes

摘要

The non-isothermal and isothermal crystallization of nanocomposites based on poly(ethylene-co-acrylic acid) copolymers having different concentration of acrylic acid and different molar mass, their Zn ionomer and ethylene-glycidylmethacrylate copolymer as matrices and organically modified montmorillonite as a nanofiller have been investigated. The influence of the presence and the concentration of clay on the kinetic parameters of non-isothermal and isothermal crystallization of the matrix polymer has been evaluated. The melting properties of the isothermal crystallized samples have been also studied. The addition of 5 or 10 wt% clay to the matrices of the polar polymers leads to a change in the mechanism of non-isothermal and isothermal crystallization. The growth of the polyethylene spherulites changes from three- to two-dimensional when the lamellar silicate is added. Moreover, the isothermal overall crystallization rate increases in the presence of clay due to the increased nucleation rate and unchanged or decreased crystal growth rate. The results have been interpreted by the influence of the intercalated structure of nanocomposites on the crystallization behavior of the polymers under non-isothermal and isothermal conditions. (C) 2006 Elsevier Ltd. All rights reserved.