The effect of core layer treatment and almond shell powder content in the glue line on the pull off adhesion sandwich panel

The aim of this study was evaluation of treatment effect of giant reed (Arundo donax) used in core layer of sandwich panel (untreated, heat-treated and hot-water-leached treatment), and also weight ratio of almond shell powder to melamine/urea formaldehyde at three levels (3:97, 18:82 and 33:67) on the dry- and wet-pull off adhesion (after 2 hours immersion in boiling water) of sandwich panel. Statistical analysis and Duncan multiple rang test showed that the type of treatment of core layer particle and ratio of almond shell powder to melamine/urea formaldehyde had the effect on the dry and wet-pull off adhesion, statistically. According to the FTIR test obtained from samples made from particle treated with hot-water, the hot-water treatment caused an increase in number of chemical bonds. Macroscopic photos, also, showed that hot-water treatment created the best surface quality in order to forming desirable bond. Generally, panel manufactured from hot-water-treated particles in core layer and 33% of almond shell powder in glue line had the highest pull off adhesion in dry (5/01MPa) and wet (2/86 MPa) conditions.