Hydrophobic treatments for natural fibers based on metal oxide nanoparticles and fatty acids

This work describes hydrophobic treatments developed for natural fibers. They involve the coating of fibers and nonwovens by metal oxide nanoparticles, namely titanium dioxide (TiO2) and zinc oxide (ZnO), followed by the application of a fatty acid. For comparison purposes, the fatty acid treatment was also applied directly on the fibers, i.e. without the intermediate nanoparticle layer. The efficiency of the treatments was assessed on recycled jute in terms of water contact angle and water drop shape retention time. In addition, the effect of the hydrophobic treatment process on the mechanical performance and thermal stability was also measured. The results show the advantage of the metal oxide nanoparticle intermediate layer in providing the natural fibers with stable hydrophobic properties. These treatments provide a nontoxic, low cost solution to make natural fibers hydrophobic, including recycled ones. This opens new opportunities for these fibers as reinforcement for composite parts.