Study on Heat Transfer in Intumescent Fire Retardant Epoxy Coatings During Combustion

ABSTRACT

The heat transfer process and combustion behavior of intumescent fire retardant epoxy (IFR-EP) coatings were studied using a cone calorimeter and multi-channel data acquisition instrument. The results showed that the combustion process of the coating and its heat transfer process were closely connected and interacted. Compared with the intumescent char layer of IFR-EP coating B, that used expandable graphite (EG) as a synergistic additive, the char layer of IFR-EP coating A, that used Sb₂O₃ and chlorinated paraffin (CP) as synergistic additives, was more effective to hinder the transfer of external heat to the interior of the sample. Various other factors, such as the content of fire retardants, can also remarkably affect the heat transfer process of the coatings. Two typical char layer physical structure models, a uniform-cellular char physical structure and a nonuniform-crack char physical structure, are presented based on our investigations of the char layers, with each being most appropriate for one of the two types of samples.

KEYWORDS:

• char structure model
• combustion
• epoxy
• heat transfer
• intumescent fire retardant coating

Acknowledgments

The authors gratefully acknowledge the financial support of China NSFC Funds (No. 51006054) and the Shandong Provincial Natural Science Foundation of China (ZR2014EEM037). This research was also supported by the State Key Laboratory of Safety and Control for Chemicals of China (SKL-023).