Heartwood and Sapwood Impregnations with Vinyl Monomers

Eight species of wood were investigated, seven hardwoods, and one softwood. These species were selected because they had both the heartwood and sapwood present in the same board. Since the wood came from the same tree, any variation within species was minimized. Flat grained boards were selected and cut into samples 2 by 2 by 10 centimeters in the longitudinal direction. Six samples of heartwood and six samples of sapwood from each species were selected for a total of 96 samples. The specimens were vacuum dried at 50?C., weighed, measured, and the densities and permeabilities determined. Heartwood and sapwood from the same species were impregnated and cured together to avoid any processing variations. After treatment, the wood-polymer combinations were vacuum dried again at 50?C., weighed, measured, and the densities and permeabilities determined. Heartwood and sapwood specimens were cut into 2 centimeter cubes for the hardness and compression tests. After treatment, the sapwood in general exhibited greater increases in compressive strength perpendicular to the grain, tangential hardness, and density than did the heartwood. Sapwood showed a greater reduction in permeability and it had a higher polymer retention, which meant that more of the calculated void volume was filled with polymer. The final physical properties average about the same for the heartwood and sapwood.

You must be logged in to download any documents. Please login (login accounts are free) or learn how to Become a Member