Reactive quaternary ammonium antimicrobial agent derived from cardanol for UV curable coating

The current research work presents an attempt to develop an antimicrobial agent from the bioresource cardanol which can be embedded in the polymer matrix to develop a UV curable coating. The brominated cardanol (BC) was synthesized from liquid bromine (Br-2) and cardanol followed by the reaction with triethylamine (TEA) to synthesize quaternary ammonium cardanol (AC). Further, the reaction with glycidyl methacrylate (GMA) gives a UV curable antimicrobial agent (AA). This AA was incorporated in the epoxy acrylate UV curable system in various proportions along with the photoinitiator and coated onto a wooden substrate. The Fourier transform infrared (FTIR) and nuclear magnetic resonance (NMR) spectroscopies and elemental analysis results revealed that the desired product has been formed. An antimicrobial test was performed with three types of microorganisms viz., bacteria, yeast, and fungi. The test results showed that the antimicrobial performance of the coatings was increased with the significant inhibition percentage values of 81.59% for gram-positive bacteria (Staphylococcus aureus), 77.12% for gram-negative bacteria (E. coli), and 73.82% for yeast (Candida albicans). Also, there was a decrease in the growth% value of the fungi (Aspergillus niger) as the concentration of AA in the system was increased. The mechanical properties of all the coatings were similar. There was a decrease in the T-g as well as in the degradation temperature of the coating films as the concentration of AA was increased, but the char yield got increased, as well. The sample with 20 wt% of AA showed the maximum amount of char yield (11.49%).

Automated summary

This research aims to develop an antimicrobial agent from cardanol for UV curable coatings, showing promising antimicrobial properties. The mechanical properties of the coatings are similar, but the degradation temperature decreases and char yield increases as the concentration of the antimicrobial agent rises.