The conventional isolation of cellulose nanofibers (CNFs) process involves high energy input which leads to compromising the pulp fiber’s physical and chemical properties, in addition to the issue of elemental chlorine-based bleaching, which is associated with serious environmental issues. This study investigates the characteristic functional properties of CNFs extracted via total chlorine-free (TCF) bleached kenaf fiber followed by an eco-friendly supercritical carbon dioxide (SC-CO₂) treatment process. The Fourier transmission infra-red FTIR spectra result gave remarkable effective delignification of the kenaf fiber as the treatment progressed. TEM images showed that the extracted CNFs have a diameter in the range of 10–15 nm and length of up to several micrometers, and thereby proved that the supercritical carbon dioxide pretreatment followed by mild acid hydrolysis is an efficient technique to extract CNFs from the plant biomass. XRD analysis revealed that crystallinity of the fiber was enhanced after each treatment and the obtained crystallinity index of the raw fiber, alkali treated fiber, bleached fiber, and cellulose nanofiber were 33.2%, 54.6%, 88.4%, and 92.8% respectively. SEM images showed that amorphous portions like hemicellulose and lignin were removed completely after the alkali and bleaching treatment, respectively. Moreover, we fabricated a series of cellulose nanopapers using the extracted CNFs suspension via a simple vacuum filtration technique. The fabricated cellulose nanopaper exhibited a good tensile strength of 75.7 MPa at 2.45% strain.

Effect of Alkaline Peroxide Pre-treatment on Microfibrillated Cellulose from Oil Palm Fronds Rachis Amenable for Pulp and Paper and Bio-composite Production

In this study, Box-Behnken design (BBD) and response surface methodology (RSM) was applied to study the effects of alkaline peroxide treatment variables (cooking time, sodium hydroxide concentrations, and hydrogen peroxide concentrations) on the pulp and paper strength properties (screened pulp yield, kappa number, tensile index, tear index, burst index), which are considered dependent variables or response variable of the extracted cellulose from oil palm (Elaeisguineensis) fronds (OPF) vascular bundle fibers. The results indicated that at the optimum operating conditions of 2.35% NaOH, 5.00% H₂O₂ and a 53.41 min cooking time, resulting maximum strength properties (tensile index, burst index, tear index,) gave 9.92 Nm/g, 6.55 KPam²/g, 6.22 mNm²/g, respectively. The study revealed that alkaline peroxide pulped fibers of oil palm frond vascular bundles could be considered a suitable alternative for paper qualities with moderate strength requirements.