The effect of concentration extender on the making of lignin phenol-formaldehyde from coconut fibre as an environmentally friendly adhesive

Abstract

This study aims to make adhesives with a variety of concentration extenders. First, the coconut husk was delignified with 25% NaOH and then precipitated with sulfuric acid. The yield of lignin from coconut coir was 38.92%, with a purity of 68%, a phenolic hydroxyl content of 2.47%, and an equivalent molecular weight of 1666.67 g/mol. Lignin was then used to synthesize phenol-formaldehyde (LPF) lignin by adding tapioca flour extender with variations of 10%, 20% and 30% of the mass of phenol through the resol method with 50% NaOH catalyst. Then the characterization was carried out using FTIR Spectrophotometer, XRD and adhesive test. The results showed that the LPF copolymer with a 10% extender was better than the LPF copolymer without an extender for wood adhesives with adhesive resistance of 955.34 N and low formaldehyde emission of 0.44 mg/L.