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Alcatrão ou creosoto de eucalipto na produção de adesivos fenólicos para colagem de madeira

1997; Brazilian Chemical Society; Volume: 20; Issue: 4 Linguagem: Inglês

10.1590/s0100-40421997000400005

1678-7064

Alexandre Santos Pimenta, Benedito Rocha Vital, Fred Y. Fujiwara,

Lignin and Wood Chemistry

EUCALYPTUS TAR AND CREOSOTE.This study has shown that Eucalyptus tar and creosote can be used in phenolic adhesive formulations (resols) for wood products bonding.Some adhesives were prepared substituting 0; 17.7; 35.0 and 67.0% of the phenol by anhydrous tar and 0; 15.0 e 28.5% by creosote.In gluing Brazilian pine veneers, eucalypt tar and creosote based adhesives required longer pressing times for curing than conventional phenol-formaldehyde adhesives.By using 13 C NMR, the number of carbons in side chains and hydroxyl, carbonyl, carboxyl and methoxyl groups related to 100 aromatic rings could be estimated in tar and creosote.In creosote, after reaction with excess formaldehyde in alkaline medium, only 0,28 hydroxymethyl groups was detected per phenolic ring.This low amount of hydroxymethylation explains the lack of reactivity in curing observed when creosote was introduced in a standard adhesive formulation.