INVESTIGADORES
ALVAREZ Vera Alejandra
artículos
Título:
Non-isothermal crystallization of PVOH-co-ethylene
Autor/es:
VERA ALVAREZ; PABLO STEFANI; ANALÍA VÁZQUEZ
Revista:
JOURNAL OF THERMAL ANALYSIS AND CALORIMETRY
Editorial:
Springer
Referencias:
Año: 2005 vol. 79 p. 187 - 193
ISSN:
1388-6150
Resumen:
Non-isothermal crystallization of polyvinylalcohol-co-ethylene with different ethylene contents was studied. Several models were used to predict the crystallization behavior of these materials under non-isothermal conditions at a constant cooling rate. Kinetic parameters determined from isothermal date were employed. Experimental data were in accordance with model prediction at low cooling rate and relative degree of crystallization lower than 0.8, but it did not fit at high cooling rate. Kinetic parameters obtained by using a non-linear regression method, i.e, Kamal?s model and Dietz?s modification, were able to describe better the non-isothermal crystallization behavior of the studied materials. The full model, that takes into account the induction and growth of the crystal during cooling under non-isothermal conditions was used to obtain a continuous cooling transformation diagrams for polyvinylalcohol -co-ethylene. Finally, non-isothermal models, coupled with the proposed expressions for induction time and kinetic constant, were used to represent the development of crystallinity during the processing of the polymer.