NOVOLAK RESIN-TYPE MOLDINGS PREPARED FROM PHENOLATED WOOD IN THE PRESENCE OF SULFURIC-ACID AS CATALYST

Birch wood meals, phenolated in the presence of sulfuric acid as catal yst, were compression-molded by using hexamethylenetetramine (HTMA) as a curing agent. The effect of combined phenol on the flexural strengt h and modulus of elasticity (MOE), Brinell hardness, and water resista nce of the phenolated-wood-based moldings was studied. Moreover, on th e basis of several factors, we examined the dynamic mechanical behavio ur of the moldings using a dynamic mechanical thermal analyzer (DMTA). The flexural strength, MOE, hardness, and water resistance of the mol dings were found to be controlled by the amount of combined phenol and at sufficient combined phenol levels were comparable to those of a co mmercial novolak-resin-based molding. Additionally, the DMTA studies s helved that the temperature dependence of the dynamic elastic modulus (E') of phenolated-wood-based moldings depends greatly on the amount o f combined phenol, filler content, HMTA content, molding temperature, moisture content, water-immersion test, heat-aging time, and frequency , and at sufficient combined phenol levels was comparable to that of t he commercial novolak-resin-based material. It could also be stated th at phenolated-wood-based moldings could be used safely within a temper ature range of 75 degrees C-165 degrees C, depending upon the amount o f combined phenol. Furthermore, the biodegradability of the phenolated -wood-based moldings was greater than that of a commercial novolak-res in-based molding.