Surficial modification of cellulose with oleic acid via amidation for developing water-resisting property

Abstract

Cellulose-based materials are currently considered prime candidates for replacing petrochemical plastics because they are biodegradable and cost-effective, while the insufficient hydrophobicity makes them fail to meet application demands, which is a primary issue to be addressed. This work developed a green, catalyst-free approach to prepare high-hydrophobicity amidated cellulose (ADC) by anchoring the COOH-containing oleic acid (OLA) onto NH2-containing aminated cellulose (AMC) via amide bonds. The unsaturated fatty acid tail provides a hydrophobic barrier in ADC films. The surface water contact angle of the ADC film reached 133° and remained above 110° for at least one hour. Subsequently, the ADC suspension was applied on the surface of paper from old corrugated container (P-OCC) by an impregnation approach to investigate the improvement of hydrophobic properties. The results showed that the hydrophobicity of P-OCC was increased by ADC, with the water contact angle reached to 132° from 0°. Noticeably, the tensile strength of the ADC impregnated P-OCC (A-POCC) also increased by 2 times. This indicates that with excellent hydrophobicity and mechanical strength, the ADC has great potential application in green functional coating materials.