The influence of mechanical pulping treatment on the physical properties of wood fibre plastic composites

Medium density fibreboard (MDF) fibres produced by a mechanical pulping process have shown potential for reinforcement in natural fibre composites (NFCs). In this work, the effect of process options, available in a pilot-scale fibre processing facility, on NFC properties were investigated. These were: a) refining energy; b) pre-treatment by sulphonation (i.e. chemi-thermo-mechanical pulping (CTMP) and c) whether the extractives stream (i.e. the plug screw pressate) was discarded or included with the fibre. There were improvements in composite performance with refining energy, although these were not strong or consistent across composite properties. The CTMP fibres gave a substantial improvement over conventional MDF fibres in flexural. tensile, and impact properties, which may be due to improved fibre-matrix interfacial properties because of better mechanical interlocking and the removal of extractives.