Flexible epoxy novolac coatings: Use of cardanol‐based flexibilizers

Abstract

Flexible epoxy novolac coatings were developed by reacting an epoxy novolac resin, poly[(phenylglycidyl ether)-co-formaldehyde] (PPGEF) with an amine curing agent, 4,4 0 -diamino-3,3 0 -dimethyldicyclohexyl methane (BMCHA), cardanol based reactive diluent (Cardolite NC-513) and two different cardanol-based flexibilizers (Cardolite NC-514 and Cardolite NC-547). The flexibilizer content was varied from 5 to 10% by weight of the resin. These resins were coated onto the stainless steel panels and tested for their gloss, cross-hatch adhesion, falling weight impact resistance, flexibility, abrasion, scratch hardness, solvent scrub resistance, and chemical resistance. The thermo-mechanical properties of these coatings were determined by TGA, DSC, DMTA, and tensile strength measurements. The cryofractured specimens were subjected to SEM analysis. The influence of structural differences of two flexibilizers on the coating properties was investigated. These coatings exhibited excellent properties and have great potential in industrial applications.

Synthesis of linear poly-cardanol and its application in rubber materials

“…Cardanol with abundant sources, low price, and excellent performance attracts the attention of researchers. There are many modified products, such as cardanol phenolic resin, cardanol-based epoxy resin, cardanol-based surfactants, polyepoxy-cardanol glycidyl ether, and so on, which are widely used in toughening [19][20][21], flame retardant [22], coating [23], adhesive [24,25], curing agents [26] and many other industrial fields. This attracts researchers' attention to study cardanol potential applications in the rubber industry [27].…”

Multi-Functional Cardanol Triazine Schiff Base Polyimine Additives for Self-Healing and Super-Hydrophobic Epoxy of Steel Coating

“…The presence of an azomethine group in an epoxy matrix was found to improved adhesion with a steel substrate, and it combined excellent controlled degradability, stability, and antimicrobial properties [27][28][29][30]. Cardanol is one of byproducts of the cashew oil industry that has attracted considerable attention to produce multi-functional epoxies and hardeners due to its cheap price, easily modified chemical structure, and presence of a phenolic benzene ring and hydrophobic alkenyl groups (unsaturated C 15 -chain) that are used to modify its chemical structure with new functional groups [31][32][33][34][35][36][37]. Bio-based cardanol epoxies have been used to improve the anticorrosive performance of steel coatings by the creating higher impedance and electrochemical potential values, but these epoxies cannot act as superior multi-functional coatings.…”

Solvent-Free Synthesis and Hydrophobization of Biobased Epoxy Coatings for Anti-Icing and Anticorrosion Applications

“…Kanehashi et al prepared and characterized the properties of cardanol-based epoxy coatings but no specific applications of the coatings were studied . Moreover, cardanol resins have been used in the synthesis of thermosets from epoxy blends , and as tougheners in epoxy polymers. − …”