Crosslinked PVA/Nanoclay Hydrogel Coating for Improving Water Vapor Barrier of Cellulose-Based Packaging at High Temperature and Humidity

Abstract

Improving the water vapor barrier of cellulose-based packaging in tropical conditions is very challenging for moisture-sensitive products. In this work, we developed a crosslinked polyvinyl alcohol/nanoclay (PVA/NC) hydrogel for paper surface coating. Layered NC and crosslinking can effectively improve the stability of PVA and block the flow paths of water molecules at elevated temperature and humidity. The result indicates that the crosslinked PVA/NC hydrogel coating (4 g/m2) can reduce the water vapor transmission rate of copy paper from 1861 g/m2/day to 195 g/m2/day at 38 °C (90% RH). The coated paper has an initial contact angle of 108° and can maintain hydrophobicity (>90°) under direct contact with water for three minutes. A Kit No. as high as 12 and a Cobb No. of 10 were also achieved by the coating.