Abstract

ALABANO, Carmen; PAPA, José; BARE, Wadou  and  GONZALEZ, Jeanette. Isothermal crystallization kinetics of irradiated HDPE/HA composites with a sterilization dose of gamma ray. Rev. Fac. Ing. UCV [online]. 2008, vol.23, n.4, pp.17-27. ISSN 0798-4065.

The objective of this work was to study the isothermal crystallization of High Density Polyethylene/Hydroxyapatite nanocomposites, with 2 and 5 phr of HA, non-irradiated and irradiated with 25 kGy (sterilization dose) of ã-Ray from a 60Co source at a rate of 4.8 kGy/h in air and at room temperature. The selected crystallization temperatures were 118, 117, 116 y 115 ºC. The crystallization kinetics was analyzed using the Avrami model whose parameters were optimized using a nonlinear regression technique. Experimental data, as well as their simulation with the Avrami model show a clear influence of the crystallization temperature, the amount of HA added and of the applied radiation. The Avrami model satisfactorily correlates experimental data for the non-irradiated samples of pure HDPE and HDPE/HA compounds at the highest temperature of crystallization (T_c). However, as the crystallization temperature decreases, the simulated curves increasingly deviate from experimental data, specifically at the highest values of the relative crystallinity. This effect is even stronger on irradiated samples of HDPE and HDPE/HA compounds.

Keywords : Crystallization; Isothermal; HDPE; Hydroxyapatite; Irradiated; ã-Ray.