An Automatic Bond Evaluation System (ABES) hot press was employed to manufacture a self-bonded joint between two veneers of rotary-cut birch (Betula pendula Roth). The hot-pressing conditions were 220 °C and 5.0 MPa, with press times ranging from 180 s to 600 s with 60 s intervals. Additionally, the log-soaking temperature (20 °C and 70 °C) and the veneer initial MC (6% and 11%) were varied to study the effect on the tensile-shear strength of the joints. For one set, the surface properties were altered by acetone extraction. The samples were tested at 11% MC. However, one set was partly duplicated and tested at 6% MC, to study how the testing conditions influenced the bond strength. The maximum average tensile-shear strength was 3.3 MPa, observed after 600 s hot pressing. The studies also included bond-line micromorphology analysis by applying SEM combined with a micromachining surface preparation technique based on UV excimer laser ablation. It was also indicated that longer hot-pressing times, lower veneer initial MC and a lower testing MC resulted in increased tensile-shear strength. Acetone extraction decreased the bond strength with increased standard deviation. Finally, the highest single and average strengths were observed for veneers from higher soaking temperature.
|Otsikko||WCTE 2016 - World Conference on Timber Engineering|
|Kustantaja||Vienna University of Technology|
|Tila||Julkaistu - 2016|
|OKM-julkaisutyyppi||A4 Artikkeli konferenssijulkaisuussa|
|Tapahtuma||World Conference on Timber Engineering - Vienna, Itävalta|
Kesto: 22 elok. 2016 → 25 elok. 2016
|Conference||World Conference on Timber Engineering|
|Ajanjakso||22/08/2016 → 25/08/2016|
SormenjälkiSukella tutkimusaiheisiin 'Tensile-shear strength studies on self-bonded 2-ply birch veneer joint manufactured and tested by applying Automated Bonding Evaluation System (ABES) hot press'. Ne muodostavat yhdessä ainutlaatuisen sormenjäljen.
Jukka Seppälä (Manager)Kemian tekniikan korkeakoulu