THE ACTIVATION OF WOOD FIBER FOR THERMOPLASTIC COUPLING, THE REACTIONOF WOOD WITH A POTENTIAL COUPLING AGENT

The reaction of pinus sylvestris with an unsaturated aliphatic isocyan ate, TMI, was studied. Using six different solvent/swelling systems, t he weight percent gains (WPG) of solid wood blocks was investigated. T MI was found to react readily with wood & WPG's of up to 74% were reco rded. The modification of the wood improved the dimensional stability, with high anti shrink efficiency (ASE) values up to 90% and low weigh t losses recorded over two 7 day water soak cycles. This evidence stro ngly suggests modification of cell wall polymers. The reacted blocks w ere characterised by FT-IR and the spectra showed good evidence of a r eaction between the -NCO and wood -OH with the introduction of a carbo nyl group at 1710 - 1720 cm(-1). There was no evidence of polymerisati on of TMI, indeed the spectra indicated the continued presence of C=C, possibly 1,1 disubstituted ethylene functionality. The activation ene rgy of the reaction was determined by measuring the WPG at 4 temperatu res. This was found to be 54 kJ/mol., comparable to that of butyl -NCO with wood.