Effect of surfactant on drying and rheology of poly (vinyl alcohol) – water coatings

Abstract

Drying studies of poly(vinyl alcohol) – water-based coatings are reported. Polymeric surfactant:poly(ethylene glycol) and fluorosurfactant:Capstone has been used to enhance the drying rate of this slow drying system. The drying rate enhanced with an increase in surfactant loading up to 10 wt%. Residual solvent content was decreased to 46.87% with 1.04% capstone loading in 5% PVA coating. Later on, there is no significant change in residual solvent due to a change in the nature of solution-viscoelasticity. Poly(ethylene glycol) can minimize residual solvent up to 20 wt% poly(vinyl alcohol). Both the increased concentration of poly(vinyl alcohol) and addition of surfactants to the coating solution exhibits a range of rheological behaviors such as Newtonian(5 wt%), shear-thinning/shear-thickening (10 wt%), and viscoelasticity(20 wt%).

Keywords:

• Thin films
• waterbased coatings
• PVA coatings
• surfactant enhanced drying
• residual solvent

Acknowledgments

The authors are grateful to the Science & Engineering Research Board-Department of Science & Technology, New Delhi, India (Project file no. EEQ/2016/000015) for the research funding. The authors are also thankful to Dr. B. R. Ambedkar National Institute of Technology, Jalandhar, India, and Thapar Institute of Engineering & Technology, Patiala, India, for providing necessary research and infrastructure facilities.