Abstract
Cationic waterborne polyurethane (CWPU) was synthesized from waste frying oil and utilized as antibacterial film coatings. Waste oil-based monoglyceride was synthesized by the alcoholysis reaction of waste oil with glycerol, while CWPUs were prepared by esterification with methylenediphenyl 4,4′-diisocyanate (MDI) and bis(2-hydroxyethyl)dimethyl ammonium chloride (BHMAC) as an internal emulsifier. The effect of internal emulsifier contents on the chemical structures and properties of the obtained polyurethanes was studied. Bactericidal activity of the obtained polyurethanes toward Staphylococcus aureus (S. aureus) and Escherichia coli (E. coli) was investigated using the time kill assay. CWPUs were successfully synthesized as confirmed by proton nuclear magnetic resonance spectroscopy (1H-NMR) and Fourier transform infrared spectroscopy (FT-IR). Effects of the internal emulsifier on particle size of CWPUs and mechanical properties of the resulting polyurethane films were investigated and measured by transmission electron microscopy (TEM). Particle size diameter of CWPUs ranged from 13.38 to 28.75 nm. The resulting polyurethane films were very pliable, with moderate adhesion and hardness. All films showed good resistance to water and diluted acid but poor resistance to dilute alkali. Obtained CWPUs provided excellent antibacterial activity, with efficiency increasing with increasing amount of BHMAC. Interestingly, antibacterial ability against S. aureus was more rapid than that against E. coli under similar conditions. Results offered an alternative utilization of waste frying oil as a sustainable raw material for the preparation of value-added polymers in the chemical industry.
Highlights
Various agricultural products have recently received increasing attention as sustainable raw materials because of environmental concerns and diminishing petroleum resources [1]
The iodine value (IV) value decreased to 42 g I2/100 g of sample and the OH value increased to 125.0 mg KOH/g of sample
Gradual increase in molecular weight contributed to the observed increase in oil viscosity and was explained by further dimerization or polymerization through peroxide products presenting in waste oil [22]
Summary
Various agricultural products have recently received increasing attention as sustainable raw materials because of environmental concerns and diminishing petroleum resources [1]. A major obstacle for industrial utilization of plant-based oils as sustainable feedstocks is competition with demand for human consumption. The annual amount of waste frying oil produced globally from households and food industries is huge. This waste oil is usually composed of many harmful decomposition products resulting from oxidation, hydrolysis, and polymerization [4,5,6]. Management of this waste is a significant challenge because unrestricted disposal contaminates water and land resources. Utilization of waste frying oil is forecast to have the potential to enhance the economy and reduce the number of waste products which negatively impact on the environment
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
