Experimental and Simulation Studies of Water Molecule Diffusion in Polyvinyl Butyral and its Effect on Thermal, Insulating and Mechanical Properties

Abstract

Water ingress can significantly affect the performance and long-term reliability of polyvinyl butyral (PVB) films. In order to predict the lifespan of PVB, the water absorption kinetics of pure PVB films and plasticized PVB films were studied. It was found that the Fick's model could fit the experimental data well, and the addition of plasticizer reduced the water absorption of PVB films. The binding process of pure PVB and plasticized PVB with water molecules was simulated using molecular dynamics, and the results showed that the simulation results were consistent with the experimental results. The effect of water molecules on the hydrogen bonding state of PVB was analyzed using FTIR, which showed that the wavelength of -OH in the PVB increased continuously with the decrease of its water content. In addition, it was found that the addition of water molecules significantly reduced the thermal, insulating and mechanical properties of PVB films.

Keywords: PVB, Water absorption, molecular dynamics simulation, plasticizers, mechanical property