In Situ Surface Treatment on All-Cellulose Composites (ACCs) Using Alkyl Ketene Dimer (AKD) via Solvent Infusion Processing (SIP)

Water repellence all-cellulose composite (ACC) was developed using alkyl ketene dimer (AKD). ACC is a novel single polymer composite (SPC), consisting of cellulose for both reinforcing and matrix phases. However, a technical challenge was observed for ACCs due to hydrophilic characteristic of cellulose, contributing to a higher water absorption, instability and deterioration of its physical and mechanical properties. In this study, ACC was prepared using solvent infusion process (SIP) and AKD treatment was performed in-situ during SIP prior to the drying process. As the results, ACC changed from hydrophilic to hydrophobic behaviour upon completion of AKD treatment. Fourier Transform Infrared (FTIR) spectroscopy examination confirmed the presence of AKD moieties on the ACC surface after the treatment. In addition, microstructure images indicated the presence of continuous and cloud-like coating appearance on the treated ACC unlike the untreated ACC. The increasing water contact angle (WCA) was also observed with the increasing AKD concentration, showing a maximum WCA of 160˚. The water content (WC) dropped up to 43% for treated ACC, indicating a decreasing trend of water content with the increasing AKD concentration, as compared to the untreated ACC. It is envisaged that the successful treatment of AKD treated ACC may avoid the potential damage of ACC in outdoor applications.