Chitosan/Cellulose/Halloysite Membranes Produced Using Solvent Casting Method

Abstract

Polymer biocomposites have attracted a lot of attention due to the increasing requirements for biomaterials to replace conventional materials. This replacement is due to the remarkable properties of biomaterials, including their biocompatibility, biodegradability and non-toxicity. Chitosan (CS) is a renowned abundantly-available biopolymer that is furnished with such properties. However chitosan is known to be unstable in acidic conditions, and it has fairly low mechanical strength and requires further improvement for various applications. This study aims to improve the properties of chitosan by making composites of CS reinforced with carboxymethyl cellulose (CMC), microcrystalline cellulose (MCC) and halloysite nanotubes (HNTs). These composites were prepared through solvent casting method and were investigated for their mechanical, chemical and morphological properties. The mechanical testing results showed that the CS/MCC membranes had the best mechanical properties, with a tensile strength (σ) of 79.98±8.12 MPa and a Young's modulus (E) of 2.44±0.21 GPa. Scanning electron micrographs confirmed that the high mechanical strength of CS/MCC membranes is attributed to better dispersion of MCC in chitosan. Infrared spectroscopy compared the chemical interactions between the main functional groups of the matrix and fillers. A surface wettability test was performed and revealed that chitosan membranes reinforced with 10 (w/w%) of CMC had the lowest (88.45°) and chitosan membrane with 5 (w/w%) HNT and 5 (w/w%) had the highest contact angle (130.83°). Addition of both CMC and MCC led to an improvement of the mechanical properties over the pure chitosan membrane, which was attributed to a significant interaction between chitosan and cellulose through hydrogen bonding.