Bonding ability of sengon wood treated with natural extracts
Wood preservation technology has been using a lot of synthetic preservatives for a long time. However, some disadvantages have been recorded such as environment quality degradation and killing more untargeted wood destroying organism than targeted one. Recently environment quality maintenance has been required causing a significant change in general wood processing technology and wood preservation paradigm. In terms of wood preservatives has changed from synthetic to natural wood preservatives application. Sengon is the fast growing wood species chosen in Indonesia to fulfill national and international wood demand. Unfortunately this wood species is class V of wood durability and has to be treated with preservatives. Glued wood products such as plywood, lamination, particleboard and fiberboard use low durability wood such as sengon. The objective of this research is to know the adhesion strength of sengon wood after treatment with the natural preservatives. This research was conducted by wood adhesion block method. The fast growing sengon plantation wood was chosen since this type of sengon wood was classified as low grade of wood quality (Class V). This type of wood had high portion of sapwood which was susceptible to wood destroying organism and absence of natural preservatives. The sources of natural wood preservative chosen were gadung tubers, pulai bark and kumis kucing leaves, while the extraction methods were hot water and alcohol toluene. The wood adhesive used was bio-industrial PVAc. Extraction procedure of natural wood preservatives followed ASTM D1110-1984 and D-1107-1996-2013. The procured naturally extracts was processed to obtain extract concentration 1 gram per liter. Wood preservative application used padding method on the wood surface by 0; 1; 2 and 3 application times. Each padding method was processed was applied after the former one was air dried. Wood adhesion test followed block type with with 196.gm-2 glue spread and cold press system. Compression shear test of block samples followed British Standard (1957). The research results showed that adhesion strength was highly significantly affected by single factor of padding application. Padding application exerted a negative correlation to adhesion strength. Increased natural preservatives treatment (padding application) on the wood surface resulted lower adhesion strength. The average sengon wood adhesion strength of control, 1; 2 and 3 padding application were 5.10; 3.00; 2.22 and 1.05 MPa respectively. The average wood failure were 69.20; 66.71; 62.12 and 45.83% respectively.