Application of waste phosphogypsum in thermoplastic and chemosetting composites

Application of thermally treated phosphogypsum as a filler for thermoplastic polymers such as low density polyethylene, polypropylene, polyamide 6 and PVC as well as for chemically cured composites based on epoxy or polyester resins has been investigated. Phosphogypsum used was a by-product from phosphorous fertilizers' industry (Table 1), and was treated by method elaborated in Poland. Amounts of phosphogypsum were in the range of 10-50 wt. % in PE-LD, PP or PA 6, 97.5-205 phr in PVC (Table 2) and 30-50 wt. % in chemically cured composites (Table 3 and 4). Phosphogypsum as filler causes similar changes of mechanical properties as another mineral fillers. Filled thermoplastic composites were tested with the aim to substitute talc or chalk with treated phosphogypsum (Table 8, Figs. 3-6). Effect of silanes as compatibilizers for thermoplastic composites was investigated, too. Composites polypropylene/phosphogypsum were used for preparation of automotive fittings instead of polypropylene/talc ones (Fig. 10). PVC compositions with treated phosphogypsum were used for preparation of flooring (Fig. 11). Chemically cured composites with treated phosphogypsum were used for preparation of self-leveling flooring.