The work described in this report involved examination of the development of IB strength in OSB panels as a function of pressing parameters and mat moisture content. Response surface methodology (RSM) was used in the design the experimental work employing a Box-Behnken design with four (4) variables (platen temperature, pressing time, moisture content (MC) of the face layers of the mat and face/core ratio). Results showed that the relationship between the study parameters and IB strength fits very well the form of quadratic polynomials. Within the limits studied, it was found that increasing the pressing time and/or temperature could significantly improve the IB strength in OSB panels. Also, the study showed that bonding strength is improved by reducing mat moisture content.
The work is also involved with the effect of resin kinetic on the bonding strength development. Several commercial phenol formaldehyde core resin were selected and characterised with a thermal analysis technique (DSC) to compare the chemical reactions and curing behaviour. The automated bonding evaluation apparatus or slap-shear test was employed to evaluate strength development of the selected adhesives as function of time, temperature and furnish moisture content. Test results showed that within the limits studied, increasing the pressing time and/or temperature could significantly improve the bonding shear. Also, the study showed that furnish moisture content and energy activity of the resin have limited effect on the bonding strength.
The study on the development IB strength as a function of resin energy activity, pressing temperature, pressing time and mat moisture content at the face layers, showed a significant effect of pressing time and temperature on the IB strength of the panel. Also resin with high activity energy was found to provide panel with low IB.