Insoluble Regenerated Cellulose Films Made from Mildly Carboxylated Dissolving and Kraft Pulps
Mohammadhadi Moradian, Md. Shahidul Islam, Theo G. M. van de Ven
Abstract
Research has been undergoing for years on the development of renewable and green polymers to replace petroleum-based plastics. Herein, inexpensive and sustainable films were made by applying some mild etherification reactions on kraft and dissolving pulps to obtain carboxymethylated fibers (CMFs). CMFs were subsequently dissolved in alkaline solutions then cast, immersed in an acid bath, washed, and dried to form regenerated cellulose-based films, which do not dissolve in water. Pulps were chemically analyzed and films were characterized by Fourier transform infrared (FTIR), X-ray diffraction (XRD), nuclear magnetic resonance (NMR), field emission scanning electron microscopy (FE-SEM), and UV–vis, and their physical and strength properties were measured. It was found that kraft pulp films were denser, stronger, more transparent and crystalline, had a smoother surface, and were more water absorbent than the dissolving pulp films due to their higher hemicellulose content. Overall, low cellulose carboxymethylation as a scalable method is promising for making biodegradable, recyclable, insoluble, transparent, and strong films that can compete with cellophane and various plastic products used in packaging.