Hardboard quality of mixed sisal, gelagah grass and empty palm oil fruit bunches bonded with tannin-formaldehyde adhesive

Wood is the raw material that is most frequently utilized in pulp industry in Indonesia. Hardboard from the wood fiber is currently faced with limited raw materials and the issue of deforestation. The utilization of nonwood fiber materials can be used as an alternative. Several substitute nonwood fiber sources, for instance, sisal, gelagah grass, and empty palm oil fruit bunches (EPOFB), can be utilized as the primary component of hardboard. The pulping method was a semi-chemical open hot soda process using NaOH concentrations of 9.0% and 10.5%. Gelagah grass pulp, EPOFB and sisal were mixed with four composition variations and then formed into hardboard with a target density of 1.00 gram/cm3. In each formula (except for control), tannin-resorcinol-formaldehyde (TRF) was applied for adhesive (4%), wax emulsion (5%) and alum (3%) was added as an additive. The hardboard was then tested for physical and strength (mechanical) properties, including density, flexural strength (MOE), fracture modulus (MOR), moisture content, water absorption, thickness expansion, internal bond strength (IB), thermal conductivity, heat resistance as well as XRD analysis. Based on the results study, the best fiber for Hardboard was EPOFB, followed by gelagah grass and sisal. Meanwhile, in the form of mixed fiber for hardboard, the order of the most prospective proportions was EPOFB (50%) + sisal (50%), gelagah grass (50%) + sisal (50%); sisal (100%); and finally gelagah grass (33.33%) + EPOFB (33.33%) + sisal (33.33%).