CHEMICAL MODIFICATION OF RUBBERWOOD FOR MEDIUM DENSITY FIBREBOARD

Rubberwood chips which have been soaked in water or a borax-boric acid solution were pulped under various conditions. The fibres from the untreated chips and produced under the mildest condition of 6 kg cm⁻² steam pressure for 10 min were subjected to different chemical treatments and then made, as with the other fibres, into medium density fibreboard. With the use of urea-formaldehyde resin, the mechanical properties of the boards from chips soaked in boric acid -sodium borate solution showed a slight improvement compared to those of boards made from untreated chips. Some improvement in mechanical properties was also observed in boards made with urea-formaldehyde resin mixed with elemental sulphur. With the use of melaminephenol-formaldehyde resin, boards made from acetylated fibres gave excellent water resistance but their mechanical properties decreased considerably. The same tendency was shown in boards made from fibres treated with formaldehyde.