Naslov
INVESTIGATION INTO THE CHANGES OF WOOD SURFACE LAYER BY MEASURMENT OF pH-VALUE
(Investigation into the changes of wood surface layer by measurment of pH-value)

Autori
Ljuljka, Boris ; Sertić, Vladimir ; Grbac, Ivica ; Jirouš-Rajković, Vlatka

Izvornik
Drvna industrija (0012-6772) 47 (1996), 3; 101-107

Vrsta, podvrsta i kategorija rada
Radovi u časopisima, prethodno priopćenje, znanstveni

Ključne riječi
Wood surface; surface pH; surface activation

Sažetak
Wood pH has been studied with regard to its affecting some change on wood surface. The change of wood surface was analysed after the following: - chemical treatment; aging in room climate; exposure to the sun, rain and surrounding atmosphere; exposure to ultraviolet radation. Each treatment was folloved by measurements of the pH and the adhesion of the NC varnish. The procedure of pH measurement on the wood surface with a combined surface electrode was devised. A 25 mm circle was drawn on the wood surface with NC varnish to prevent spreading along the fibers. Into the circle 0,75 ml of water was applied, the electrode plunged in. After 5 minutes, the pH was measured. Within this time, no negative effects of carbon dioxide on the water pH were established. The research was done on fir, beech, oak and poplar. After chemical treatment, the pH on the wood surface varied depending on the chemical used but some general conclusions about the effects of pH on the following adhesion may be drawn. Summer sunlight quickly reduces the adhesion of varnish on beechwood, increasing the pH of wood suraface. Sunlight, and in combination with the rain in February, lasting 10 days, does not affect adhesion significantly. Instead, the surrounding atmosphere seems to have a greater influence in this time period. Varnish adhesion may be enhanced with a certain dose of UV-light. It is likely that maximum adhesion is achived by the highest pH. Wood pH should be regarded as an indicator of chemical changes rather than cause of change.

Izvorni jezik
Engleski

Znanstvena područja
Biotehnologija

POVEZANOST RADA