The European aspen (Populus tremula L.) is a fast-growing low density hardwood species used in veneer and the pulp and paper industry. Shortages and/or high prices of high-quality wood species, such as birch, increase the need to find alternative materials in the form of faster growing and readily available wood species, as is European aspen. One process that has been developed for birch, but not yet for aspen, is peeling thin veneer (0.5 mm thickness or lower) with a smooth surface. Currently, there exists a research gap, because no conventional peeling or preconditioning parameters allow for thin aspen veneer to be peeled.
The aim of this study was to find optimal parameters for thin aspen veneer peeling (0.3 mm). Since European aspen contains slightly more cellulose than birch but less structural reinforcement from lignin [1], it was hypothesized that lowering the preconditioning temperature would help maintain the integrity of the cellulose fibres during rotary peeling. This adjustment may facilitate the production of thin aspen veneer by reducing fibre disruption. Research objectives for this study are: to evaluate different preconditioning temperature effects on veneer and surface characteristics of thin aspen veneer with 0.3 mm thickness; to evaluate the effect of different compression ratios on veneer and surface characteristics of thin European aspen veneer; to evaluate the effect of different peeling speeds on veneer and surface characteristics of thin European aspen veneer; to research significant differences and correlations between surface characteristics of veneer peeled with different peeling parameters and preconditioned with different temperatures.
Keywords: European aspen, temperature, peeling speed, compression ratio, contact angle
Authors
Heikko Kallakas
Laboratory of Wood Technology, Department of Material and Environmental Technology, Tallinn University of Technology, Estonia
Kaur Tootsi
Laboratory of Wood Technology, Department of Material and Environmental Technology, Tallinn University of Technology, Estonia
Catherine Kilumets
Laboratory of Wood Technology, Department of Material and Environmental Technology, Tallinn University of Technology, Estonia
Jaan Kers
Laboratory of Wood Technology, Department of Material and Environmental Technology, Tallinn University of Technology, Estonia
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