Evaluation of MDF bonding with polyurethane of castor oil

Adhesives used to bond the wood panels are petroleum-based and has volatile organic compound, VOCs. Harmful substance when inhaled by human being and can cause different problems, such as cancer. As an alternative to replace these adhesives is to use the polyurethane derived from castor oil (PU), a renewable resource that can be used to structural applications, indoor and outdoor environments. It is weather resistant and has good mechanics properties. The aim of this paper is to evaluate the mechanical resistance of glued joint with PU biding MDF panels. It was produced raw MDF samples glued two by two with 0.05 g of adhesive in 1 cm2. Where 6 samples were used with PVA adhesive, 6 with contact adhesive and 6 with PU. After 72 h it was applied a mechanical analysis technique of shear bond strength, according to the standards ASTM D 3983-93 and ASTM D897-95A. The results shows the shear average resistance of PU was 12.67 ± 2.26 MPa, whereas for the PVA adhesive was 2.55 ± 0.19 MPa and the contact adhesive was 3.26 ± 0.63 MPa. It is conclusive the polyurethane derived from castor oil can be used to bind MDF panels, due to its superior shear average resistance compared to PVA and contact adhesives.