Characterization of Coconut Leaf Fiber-Based Packaging Paper with Different NaOH Concentrations and Delignification Temperatures

Coconut leaves are potential for improving packaging paper quality. This study aimed to evaluate the effects of NaOH concentration and delignification temperature on the characteristics of packaging paper based coconut leaf fibre. A two-factor randomized block design was applied using three NaOH concentrations (2.5%, 5.0%, and 7.5%) and two delignification temperatures (85 °C and 100 °C), with three replications. The evaluated parameters included tensile strength, tear resistance, water vapor transmission rate (WVTR), grammage, functional groups by Fourier Transform Infrared (FTIR), and surface morphology by Scanning Electron Microscopy (SEM). Data were analyzed using analysis of variance followed by Duncan’s Multiple Range Test (5%). The results showed that NaOH concentration and delignification temperature significantly affected all measured properties. The optimum treatment was 5% NaOH at 85°C, producing a tensile strength of 1.94 kN/m, tear resistance of 2.38, WVTR of 35.86 g/m²/day, and grammage of 143.91 g/m². The addition of delignified cellulose to recycled paper reduced the intensity of absorption bands at 1723 cm⁻¹ and 1572 cm⁻¹ (corresponding to C=O vibrations of hemicellulose/lignin and lignin aromatic rings). This indicates the removal of lignin and hemicellulose components results in a more dominant cellulose fraction. The SEM images showed a more homogeneous and compact fibre structure than recycled paper without cellulose addition.