Gypsum reinforced using hemp fibers: Enhanced interfacial compatibility by dual-modification strategy

Natural fibers are promising as enhancements for gypsum. Herein, the effect of using untreated, NaOH-modified, and dual-modified hemp fibers on enhancing performances of gypsum composites is examined. The dual-modification strategy applies secondary treatment on NaOH-treated fibers with NaClO, polyoxyethylene, or Tween-80. The fibers and composites are characterized by SEM, ATR-FTIR, XRD, mechanical strength, etc. The secondary modification enhances interfacial compatibility between gypsum and fibers. Compared with pure gypsum, the elastic modulus and bending strength of the composites with dual-modified fibers increase by 56% and 42%, respectively. Hydration process reveals that dual-modification using polyoxyethylene contributes to form dense, compact composite structures.