Thermal fractionation of polymers

Thermal fractionation techniques offer quick and practical ways to evaluate chain heretogeneities in semicrystalline thermoplastic materials by employing carefully designed thermal cycles in a Differential Scanning Calorimeter (DSC). They are particularly useful to study the degree and distribution of short chain branches produced by the copolymerization of ethylene with alpha-olefins, however, other materials have also been recently examined by these techniques. Thermal fractionation provides an alternative to experimentally more time consuming and complicated fractionation techniques that involve preparative or analytical fractionation in solution. In this review, a particular emphasis is made on the two techniques most commonly applied in the literature: step crystallization from the melt (SC) and successive self-nucleation and annealing (SSA). The numerous applications that have been recently developed are also reviewed. (c) 2005 Elsevier Ltd. All rights reserved.