ISOTHERMAL CURING KINETICS OF POLYMETHACRYLIMIDE/NANO-SiO2 COMPOSITES BASED ON A DYNAMIC THERMOMECHANICAL ANALYSIS

The isothermal curing kinetics of polymethacrylimide/nano-SiO2 composites were investigated using a dynamic thermomechanical analysis. relative conversion was defined with the storage modulus. Avrami model-fitting method, Friedman method and integral applied to analyze kinetics. modulus loss increased appreciably, spanning three orders magnitude throughout curing. frequency correlation noticeable at 180 °C because glass transition took place when degree not high enough. analysis gave good fits for experimental data. activation energy calculated equation changed from 65.46 kJ/mol 25.28 180–190 °C, while 190–200 107.14 63.82 kJ/mol. model-free revealed dependence on conversion. 104.3 130.6 use ranged between 0.4–0.8. Similarly, 71.5 103.4 When exceeded 0.8, decreased gradually. mobility reactive groups hindered crosslinking density composite much higher. became diffusion controlled. PMI/SiO2 greater than that PMI, which could be attributed hindrance effect caused by nano-SiO2.