화학공학소재연구정보센터
Thermochimica Acta, Vol.664, 32-38, 2018
A study of chloro-p-xylylene polymerization kinetics using high-vacuum in situ differential scanning calorimetry
The polymerization kinetics of chloro-p-xylylene in condensed state was studied by in situ non-isothermal DSC measurements conducted at different heating rates in the range from 1.1 to 6.3 degrees C min(-1), using a custom-made heat-flux calorimeter integrated into a vacuum vapor deposition polymerization reactor. The total exothermal effect of polymerization reaction (Q = 71 +/- 9 kJ mol(-1)) and its temperature range (-140 to -80 degrees C) were determined. The differential isoconversional method by Friedman was applied for the kinetics analysis. The effective activation energy increases monotonically with the degree of conversion from about 36 to 55 kJ mol(-1). Such behavior was associated with transition to diffusion-limited regime of the polymerization reaction. The reaction model f(alpha) was evaluated using a model-free method based on the use of the compensation effect. The calculated f(alpha) values were independent on the heating rate and correspond to the second-order reaction model f(alpha) = (1 - alpha)(2) in the conversion degrees interval of 30-90%.