H och2ch2 noh

All chemicals (analytical grade) were utilized in this research without additional purification: titanium (IV) isopropoxide (Ti(OC₃H₇)₄, Sigma Aldrich, St. Louis, MO, USA, 98.0%), zinc acetate ((CH₃CO₂)₂Zn, Sigma Aldrich, 99.99%), isopropyl alcohol (C₃H₈O, Sigma Aldrich, ≥99.5%), hydrochloric acid (HCl, Sigma Aldrich, 37.0%), sodium hydroxide (NaOH, Sigma Aldrich, ≥85.0%), hydrogen peroxide (H₂O₂, Sigma Aldrich, 35%), sodium metasilicate nonahydrate (Na₂O₃Si·9H₂O, Sigma Aldrich, ≥98.0%), kaolin (Sigma Aldrich), sodium dodecyl sulfate (CH₃(CH₂)₁₁OSO₃Na, Sigma Aldrich, ≥99.0%), poly(ethylene glycol) (H(OCH₂CH₂)_nOH, Sigma Aldrich).

Oil palm EFB fibers procured from Szetech Engineering Sdn Bhd (Selangor, Malaysia) were milled and sieved at desired sizes of 106 to 500 µm. Preparation of cellulose isolation and the defibrillation processes were done using formic acid, 90%, hydrogen peroxide, 30%, sodium hydroxide, and iron (II) sulfate heptahydrate received from Merck, Darmstadt, Germany. While the surface-grafted CNF were formulated using PEG with an average M_n of 4000 (Linear formula, H(OCH₂CH₂)nOH) (Sigma-Aldrich, Darmstadt, Germany), synthesized reduced graphene oxide with graphite flakes (Ashbury, Inc., Ruckersville, VA, USA), phosphoric acid, 85%, potassium permanganate, 99.9%, hydrogen peroxide, 30%, and sodium borohydride (Merck, Darmstadt, Germany). In 3D printing, commercial UV-curable resin was used with a composition of 45–47 wt% polyurethane acrylate, 34–36 wt% morpholine, and 15–17 wt% tripropylene glycol diacrylate (Wanhao Precision Casting Co. Ltd. (Jinhua, China)), and isopropyl alcohol (Merck, Darmstadt, Germany) was used to remove the residual resin on the 3D-printed samples.