Utilization of water-soluble chitosan as a sizing agent incorporated in a paper composite: effects of pulp weight and water-soluble chitosan concentration

Currently, water-soluble chitosan (WSC) has been developed through a pressurized hydrolysis process. Compared to acid-soluble chitosan, the WSC is soluble in water, and it is used in many applications such as pharmaceutical, food, and composite industries. The FTIR and thermal properties such as TGA were investigated to determine the effect as a sizing agent material on paper composite. Furthermore, the influence of pulp weight variation of 1, 1.5, and 2 g and WSC concentration of 0.25, 0.5, 0.75, and 1.0% (w/v) on the physical, mechanical, and antimicrobial properties of the paper composites were studied. The density and grammage increased after incorporating due to the increase in the dissolved concentration of WSC. The mechanical properties, such as tensile strength, tensile modulus, and elongation at break, were also improved to the highest value of 2.76 MPa, 170.58 MPa, and 2.67% at 1.0% WSC and 1 g pulp concentration, respectively. The paper composite incorporated WSC also showed antimicrobial activity against Gram-positive (Staphylococcus aureus) bacteria and Gram-negative (Escherichia coli). However, increased concentration of WSC up to 1% caused inhibition zone of Gram-negative (Escherichia coli and Salmonella typhi) and Gram-positive (Staphylococcus aureus and Bacillus subtilis) bacteria.