Simultaneous drying and densification of silver birch (Betula pendula L.) veneers: analysis of morphology, thickness swelling, and density profile

摘要: In this study, birch (Betula pendula L.) veneers were simultaneously densified and dried using a contact drying method at pressures of 1.5 3 MPa 130 °C compared with veneer in laboratory-scale convective type dryer. Compression rate, thickness swelling, the density profiles investigated. Furthermore, microstructure was studied by scanning electron microscopy (SEM). A maximum compression rate 9 % achieved pressure MPa. Under these conditions, were, on average, from 504 to 574 kg m−3 (approximately 14 %). After water soaking, full set-recovery—recovery initial thickness—occurred. However, swelling lower for veneer. Density measurements showed that densification occurs throughout veneers. The SEM images surface smoother, whilst no cracks detected due densification. Densification seemed occur vessels. Typically, rays bent when there vessel nearby.