Effect of Hybridization of Inorganic/Organic Acid as the Liquefaction Catalyst on the Properties of Liquefied Kenaf Polyols

Production of kenaf polyols (KP) via liquefaction process was carried out using polyethylene glycol 400 and glycerol as the liquefying solvent. Optimization of parameters such as temperature, time, and the ratio of catalyst composition was done extensively. The effect of the hybridization of inorganic acid (sulphuric acid) and organic acid (lactic acid) as the liquefaction catalyst on the liquefaction product was studied. The results demonstrated that the lowest amount of residue (10.1%) was obtained at 160 °C with 3:1 (sulphuric acid: lactic acid) ratio of catalyst composition for 90 min. The hydroxyl (OH) number and viscosity of the kenaf polyol were examined. FTIR and NMR analyses revealed that most kenaf cellulose, hemicellulose, and lignin were degraded. XRD analysis was employed to examine the crystallinity index of kenaf residues (KR) at different temperatures, times, and catalyst ratio compositions. The morphology of KR at different temperatures was examined by using SEM analysis. The results showed that a smooth-surface KR was obtained at the optimum temperature (160 °C), indicating most of the cellulose was already decomposed at 160 °C. The optimized KP with OH number of 335.6 mg KOH/g and viscosity of 690 cP was used for the making of bio-based rigid polyurethane foam which is denoted as KPUF. The properties of KPUF and PUFs based petroleum polyol (PPUF) were compared. The density of KPUF (68.2 kg/m 3 ) is lower compared to PPUF (131.9 kg/m 3 ). The cellular structure and larger average cell diameter (0.617 mm) of KPUF enhance the water absorption ability which demonstrated that KPUF is capable to be utilized as growing media in the hydroponic system.