Calorimetric Analysis of an Isotactic Polypropylene Gamma-Irradiated in Vacuum

Author: Spadaro G.   Valenza A.  

Publisher: Springer Publishing Company

ISSN: 1388-6150

Source: Journal of Thermal Analysis and Calorimetry, Vol.61, Iss.2, 2000-08, pp. : 589-596

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Abstract

The molecular modifications induced in an isotactic polypropylene gamma-irradiated in vacuum under a complete set of experimental conditions were studied by means of calorimetric analysis. In a previous paper [1], the influence of the irradiation parameters, the total absorbed dose, D, and the dose rate, I, was analyzed and a simple kinetic model based on the rates of the main reactions occurring during irradiation, i.e. β-scission, addition to double bonds and termination, wasalso discussed. It is now shown how thermal analysis confirms the model forecasts and in particular the existence of the ‘inversion conditions’: below them the main effect is molecular degradation, while above them the main effects are chain-branching and cross linking.