Synthesis and Characterization of Silver Nanoparticles-Embedded Alkyd Resins derived from Castor Seed Oil

Abstract

Alkyd resin (CSOR) was prepared from castor seed oil (CSO) by alcoholysis with glycerol to form monoglyceride and polycondensation with phthalic anhydride to form the alkyd resin (CSOR). The formation of resin was monitored by drop in acid value as the reaction progresse s. Silver nanoparticles (AgNPs) were also synthesized from silver benzoate solution (SBS) by one step in-situ reduction method. The nanoparticles were mixed with CSOR in toluene to form a homogeneous mixture of silver nanoparticles-embedded alkyd resin (AgNPs -CSOR). The formation of AgNPs was confirmed by colour change, surface plasmon resonance at 455 nm as observed by UV -visible spectrophotometry and the presence of Ag-O band at 696 cm -1 as shown by FTIR spectroscopy. The antimicrobial activity of SBS, CSO, CSOR, and AgNPs-CSOR were evaluated against Escherichia coli, Salmonella typhi, Staphylococcus aureus, Aspergillus flavus, Aspergillus fumigatus and Mucor spec ies in nutrient agar using the disc diffusion method. The appearance of higher zone of inhibition in AgNPs-CSOR clearly indicated a higher antimicrobials activity when compared to SBS, CSO and CSOR. The performance characteristics of the CSOR and Ag-NPs-embedded alkyd resins as ingredients in surface coatings were further evaluated. The results obtained revealed that the paint films air -dried faster, show good solvent resistance and excellent light fastness which suggest the potentiality of AgNP-CSOR as binder in the formulation of antimicrobial surface coatings.