Production of quaternary ammonium compounds added antimicrobial polyurethane foams

With the growing awareness of pathogenic microorganisms, there is an increasing need for antimicrobial materials. Flexible polyurethane foams (FPUs) used in various application areas such as mattresses, beds, pillows, filter elements, kitchen cleaners, body sponges, and etc. are good reservoirs for microorganisms and often required to have an antimicrobial property. In this regards, to impart antimicrobial functionality to polyurethane foams, a quaternary ammonium polymer (QAP) having a polyol main chain was incorporated into a foam structure by covalent bonds which is dramatically important to prevent migration of agents from the porous structure. QAP was added to a commercial formulation in various amounts between 1 to 5 wt%. The structures of the produced foams and their QAP content was characterized by FTIR and EDXRF analyses. A linear polymer of QAP was also synthesized to support our investigations. The morphological changes such as the cell size and the cell structure of the produced foams were observed with SEM. TGA and DMA analyse were applied to examine the thermal properties of the produced foams. 1 wt% QAP added foams showed structural and thermomechanical properties very similar to the unmodified foams. In addition, while the unmodified foam did not show any antimicrobial activity, the QAP-added foams provided significant inactivations against Staphylococcus aureus, yeast and mould at concentrations of about 102 and 103 colony-forming unit (CFU) within 5h of contact time. Antimicrobial test results showed that addition of minute amount of QAP can significantly improve the biocidal performance of the produced foams without deteriorating the commercial formulation.