Synergistic effect of PS and crosslink density on performance properties of epoxy coatings cured with cardanol based multifunctional carboxyl curing agents

In the present study, phosphorus-sulphur containing di and tetra functional carboxyl curing agents were synthesized from renewable resource, cardanol and used in the preparation of high performance epoxy coatings. Structure of the curing agents was analysed by evaluating its acid and iodine number as well as spectroscopic and chromatographic techniques. Coatings were formulated by varying the ratio of epoxy adduct to curing agents on equivalent basis such as 1:0.6, 1:0.8 and 1:1. Further, the prepared coatings were characterized for mechanical, chemical, optical, thermal, anticorrosive and flame retardant properties. It was concluded that, with increase in concentration of flame retardant curing agents, anticorrosive as well as flame retardant properties of the coatings improved. This enhancement in the properties could be related to the synergistic effect of phosphorus and sulphur as well as chemical structure of curing agents.