Synthesis and Characterization of Polyesteramide Resin from Acacia auriculiformis Seed Oil for Surface Coating Application

Acacia auriculiformis seed oil (ASO) contains linoleic acid (72%) and vernolic acid, which are capable of rendering it as a salient resource for coating applications. In this investigation, ASO a non-conventional source, was first converted to its fatty acid (AFA), followed by aminolysis and esterification to produce an AFA-based polyester amide resin (APEA), using toluene as an azeotropic solvent. Structural confirmation of APEA was performed by FTIR-ATR and (HNMR)-H-1 spectroscopy. The AFA and APEA resin were characterized and compared with conventional soybean oil-based polyester amide resins (SPEA). The thermal stability of SPEA (270 degree celsius ) and APEA (274 degree celsius ) resins was determined and compared. Films were produced by curing the resins with melamine-formaldehyde and aliphatic poly-isocyanate and characterized by mechanical, and chemical resistance tests. These tests revealed that APEA has enhanced chemical resistance and scratch hardness than SPEA. The surface morphology of PEA resins was determined by Scanning electron microscopy (SEM) which shows PEA is compatible with these curing agents that contain different true solvents (based on polarity). To study the corrosion resistance properties, a paint primer was formulated with the resins and 5% zinc phosphate. The metal content of the cured primer film was analyzed by Inductively coupled plasma-optical emission (ICP-OE) spectroscopy. All the findings prove that ASO-based PEA exhibited better performance than the soya-based PEA. The APEA can be used as binders in coating formulations to improve the mechanical as well as corrosion resistance properties.