Abstract: The aim of this work is to make use of phosphogypsum (PG) waste material, which is produced in phosphoric acid and phosphate fertilizer manufactures. A number of wood adhesive formulations based on polyvinyl acetate (PVAc) polymer and phosphogypsum as a filler have been prepared, using different percentages of phosphogypsum, ranging between 5 similar to 20 wt pet. The prepared formulations were tested for adhesion strength and compared with both natural and pure gypsum fillers. The results indicate that PG improves the adhesion strength when 5 wt pet added, and that may be due to filling the porous surface of wood with the fine particles of PG, as well as coating the particles of the filler (PG) with PVAc units. Also, a number of formulations based on urea-formaldehyde polymer have been prepared using phosphogypsum as an active filler in the ratio of 40 similar to 75 wt pct to prepare composite materials used for some decoration purposes and construction. Mechanical, physical, and thermal properties of these formulations were studied. Also, the activation energy was calculated. The results indicate that PG without acid hardener can be used for preparation of composite materials based on urea-formaldehyde between 40 similar to 63.64 wt pct for construction purposes in the humid atmosphere, while between 63.64 similar to 75 wt pct for decoration purposes. The improvement of the physical, mechanical and thermal properties of the composite material may be attributed to the simultaneous hydration hardening action of phosphogypsum and the presence of 0.8% P2O5. These effects act as an active hardener for urea-formaldehyde resin and accelerate the cross-linking and network formation reinforced by the fine dusty inorganic particles of PG. The advantage of this method is to prepare composite material gypsum-urea-formaldehyde, which achieves the utilization of large amount of PG, reducing the price of the main product phosphate, minimizing the pollution and producing new materials which possess high thermal resistance, good mechanical properties and water resistance that are suitable for construction panels.

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