The swelling of wood in polar organic solvents

The effectiveness of dimethyl sulfoxide, dimethylformamide, N-methyl pyrrolidone, and pyridine in swelling yellow birch, beech, white pine, and Douglas-fir was determined. Changes in the radial and tangential dimensions during simple immersion were followed until maximum swelling was obtained. The complete swelling behavior in cases of rapid swelling was found to be described by the hyperbolic formula: swelling at time t = equilibrium swelling -- b/time. b is the swelling resistance coefficient. For slower swelling, in the initial period the swelling is directly proportional to time, not to its square root. Birch was swollen the most by solvents, and pine the least, in relation to their densities. Beach and pine swelled the fastest, while Douglas-fir was most resistant. Dimethyl sulfoxide caused the greatest final swelling, but dimethylformamide swelled wood more rapidly. The latter solvent could be used with simple immersion, except with fir. To swell wood effectively with dimethyl sulfoxide would require a vacuum impregnation process.On d\ue9termine l'efficacit\ue9 de quatre solvants dans le gonflement de quatre essences en enregistrant les changements radiaux et tangentiels. Dans les cas de gonflement rapide, la formule hyperbolique d\ue9crit les r\ue9sultats. Dans les cas de gonflement plus lent, la vitesse initiale est lin\ue9aire. Le bouleau gonfle le plus et le pin le moins. Le h\ueatre et le pin gonflent le plus rapidement et le Douglas vert le plus lentement. Le sulfoxyde de dim\ue9thyle produit le gonflement final le plus consid\ue9rable, mais le dim\ue9thylformamide produit le gonflement le plus rapide.Peer reviewed: NoNRC publication: Ye