Application of non-isothermal cure kinetics on the interaction of poly(ethylene terephthalate) - Alkyd resin paints

Samples of paint (P), reused PET (PET-R) and paint/PET-R mixtures (PPET-R) were evaluated using DSC to verify their physical-chemical properties and thermal behavior. Films from paints and PPET-R are visually similar. It was possible to establish that the maximum amount of PET-R that can be added to paint without significantly altering its filming properties is 2%. The cure process (80-203 degrees C) was identified through DSC curves. The kinetic parameters, activation energy (E-a) and Arrhenius parameters (A) for the samples containing 0.5 to 1% of PET-R, were calculated using the Flynn-Wall-Ozawa isoconversional method. It was observed that for greater amounts of PET-R added, there is a decrease in the E (a) values for the cure process. A Kinetic compensation effect (KCE), represented by the equation InA=-2.70+0.31E(a) was observed for all the samples. The most suitable kinetic model to describe this cure process is the autocatalytic Saestak-Berggreen, model applied to heterogeneous systems.