ABSTRACT
Polyamide is a family of thermoplastics used for producing components with tight dimensional tolerance, such as gears for electronics products and small filters for fuels in the automotive industry. The dimensional control of these parts is intrinsically related to the contraction associated to the crystallization process during their injection molding . Therefore, the purpose of the present work was to calculate the non-isothermal crystallization constant of a polyamide 66 sample using the Master Curve Approach for simulation of processing. Non-isothermal crystallization experiments were carried out in a differential scanning calorimeter, DSC, at several cooling rates. The original DSC curves were corrected for the temperature lag between the sample and the DSC furnace. The Nakamura equation and the non-isothermal crystallization constant obtained by the Master Curve Approach were employed to simulate the curves of relative crystallinity as a function of temperature, for the different cooling rates. It was tested the influence of different initial relative crystallinity for the differential form of the Nakamura model. Such analysis is not frequent in literature. The generated curves presented good agreement with the experimental data for this polyamide sample, using 10-5 as the initial relative crystallinity. Therefore, this kinetic model in association with its non isothermal crystallization constant determined via Master Curve Approach showed to be a good option for simulation of the solidification process of the polyamide 66 during the injection molding.
Keywords:
Non-isothermal crystallization; master curve approach; polyamide 66; temperature lag
