A study of p-xylylene polymerization kinetics using high-vacuum in situ differential scanning calorimetry

作者：Streltsov Dmitry R^*; Buzin Alexander I; Dmitryakov Petr V; Karnasa Pawel; Ivanov Dimitri A; Chvalun Sergei N

来源：Thermochimica Acta, 2016, 643: 65-72.

DOI：10.1016/j.tca.2016.09.016

• Poly(p-xylylene)
• Vapor deposition polymerization
• Isoconversional methods
• Reaction model

The polymerization kinetics of p-xylylene in condensed state was studied by in situ non-isothermal DSC measurements, using a custom-made heat-flux calorimeter integrated into a vacuum vapor deposition polymerization reactor. The temperature range (-110 to -75 degrees C) and the total heat effect (Q = 86 +/- 8 kJ mol(-1)) of the polymerization reaction were found to be almost identical to the values previously measured ex situ with a commercial Perkin Elmer DSC7 calorimeter. The differential isoconversional method by Friedman was applied for the kinetics analysis. The effective activation energy exhibits variation with the degree of conversion in the range from 30 kJ mol(-1) to 50 kJ mol(-1) indicating the complexity of the reaction mechanism. To evaluate the reaction model f(alpha) a model-free method based on the use of the compensation effect has been employed. The calculated f(alpha) values are adequately fitted to the Avrami-Erofeev A2 model in the conversion degrees interval of 20-80%. The discrepancy observed at the end of the reaction is probably due to diffusion control of the reaction, whereas the complexity of the reaction mechanism can be a reason of the discrepancy at low degrees of conversion.

• 出版日期2016-11-10