THE MANUFACTURE OF ROOFING PANELS FROM SISAL FIBER REINFORCED COMPOSITES

Sisal fibre is a vegetable fibre having a specific strength and stiffness that compare well with those of glass fibre. The fibre surface can be modified by chemical treatment to create an interface that is fairly compatible with most thermosetting resin matrices. Most synthetic resins are, however, more expensive than the sisal fibre, making these composites less attractive for low -technology applications. Cashew nut shell liquid (CNSL) has been identified as a cheap naturally occurring phenol-based resin. It has been condensation polymerized successfully with formaldehyde in the presence of a caustic soda catalyst to give a fast curing resol-type resin. Sisal fibre in the form of plain woven mats has been mercerized and then bonded with a CNSL-formaldehyde resin matrix in a compression mould to produce corrugated composites. The composite system and manufacturing processes have been examined and it has been found that the corrugated composites are suitable for roofing and other construction purposes in tropical developing countries.