The use of SSA fractionation to detect changes in the molecular structure of model ethylene-butene copolymers modified by peroxide crosslinking

CLAUDIO J. PÉREZ, N. VILLARREAL, J.M. PASTOR, M. D. FAILLA, E. M. VALLÉS AND J.M. CARELLA

POLYMER DEGRADATION AND STABILITY

Elsevier

Año: 2009 vol. 94 p. 1639 - 1645

0141-3910

Four model ethylene-butene copolymers of different molecular weights modified with various concentrations of peroxide were analyzed by the Successive Self Annealing method. All the original copolymers had the same intra and intermolecular homogeneous branching distribution along the linear chains and a content of about 2.4% mol of ethyl branches. The copolymers with average weigth molecular weigths of 29000, 49000, 81000 and 125000 g/mol were modified with different amounts of 2,5-dimethyl-2,5-di(tert-butyl peroxy)-hexane (DBPH). The changes introduced on the molecular structure by the reaction with the peroxide affect the semicrystalline structure of the material. The alterations observed in the crystal thickness distributions of the material as a consequence of the modification procedure are in accordance with the modifications on the molecular structure originated by the peroxide reaction.