Evaluation of N,N-dibutyloleamide as a bifunctional additive for poly(vinyl chloride)

Fatty acid derivatives are considered promising eco-friendly plasticizers for poly(vinyl chloride) (PVC) resin, an alternative to petroleum-based plasticizers. In particular, biologically active fatty amides seem especially attractive additives for PVC, which may combine the properties of plasticizer and antimicrobial agent. In this study, tertiary fatty amide, N,N-dibutyloleamide (DBOA) was synthesized and evaluated as dual functional additive for PVC. Homogeneous PVC/DBOA composite films were prepared by solvent casting. According to the results of differential scanning calorimetry analysis, the introduction of DBOA (20 and 30 wt%) into PVC reduced its glass transition temperature by 31 degrees C and 37 degrees C, respectively. This reveals limited plasticizing effect of DBOA on PVC, which is common for secondary plasticizers. PVC/DBOA films also showed improved elasticity, which manifests as an increase in elongation at break by 70-80% compared with neat polymer. The thermal degradation point of PVC/DBOA blends is higher than the actual temperature of PVC processing by common methods. The additive has also good resistance to leaching by water. Antimicrobial activity of DBOA was studied by common disc diffusion method against Gram-positive and Gram-negative bacteria and fungi, including clinically resistant isolates. The compound was found to be active against Staphylococcus aureus, Escherichia coli, as well as Acinetobacter baumannii. Overall, the obtained results indicate that DBOA is a promising additive for PVC resin, since it can play a role of both plasticizer and antibacterial agent. PVC/DBOA blends may have great potential as new performance materials for medical and domestic purposes.