Fiberboards based on filled lignin resin and petiole fibers.

Fiberboards were manufactured from filled phenolic resins (lignin-formaldehyde or glyoxal) and petiole date palm fibers. Lignin was obtained from paper industry waste black liquor. To improve lignin reactivity and increase the bonding strength between matrix and fiber, phosphogypsum (PG) was used as a filler in the resin formulation from 1 to 3 wt%. Phosphogypsum exhibited excellent performance as binder; this was verified by a decrease in the gelation time and an increase in internal bond (IB) in fiberboards. The analysis confirmed that resin reactivity depends on aldehyde types (glyoxal or formaldehyde) and PG proportion. Most of the obtained boards were of good quality [modulus of elasticity (MOE) up to 1230 MPa; modulus of rupture (MOR) up to 25 MPa; internal bond (IB) up to 0.23 MPa; water absorption (WA) up to 28%]. [ABSTRACT FROM AUTHOR]