Thermal Characteristics of Propargyl Ether Phenolic Resins

Abstract

Addition curable propargyl ether phenolic resin of varying degrees of propargylation showed noticeably improved thermal stability in the lower temperature regime vis-à-vis cured resole. The crosslinking generated by the cycloalipahtic and linear polynene groups caused rapid decomposition at higher temperatures leading to a reduced char-content. The kinetics of non-isothermal decomposition showed the degradation occurring in two defined kinetic steps. The kinetic parameters computed from the mass-loss data showed an inconsistent variation in activation energy with composition. However, the computed rate constants confirmed that the first stage decomposition is facilitated by an enhanced propargyl content. The second step, associated with the carbonization process was systematically facilitated by enhanced crosslinking. Moderate propargyl functionalization was conducive for better thermal stability and anaerobic char residue. Analyses of char obtained by pyrolysis at 900°C showed it to be incompletely carbonized and amorphous in nature.

Keywords:

• Propargyl ether resins
• Addition-Cure phenolics
• Thermal decomposition kinetics
• Pyrolysis

Acknowledgments

The authors are grateful to their colleagues in the Analytical and Spectroscopy Division for support in various analyses. The Director, VSSC is thanked for permission to publish the results. R. L. Bindu acknowledges CSIR, New Delhi for a fellowship.