Surface quality sensing of trembling aspen (Populus tremuloidesMichx.) veneer products by near infrared spectroscopy

Abstract

The potential of near infrared spectroscopy (NIRS) to estimate wood moisture content (MC), surface energy characteristics and adhesive bond strength were evaluated on aspen (Populus tremuloides Michx.) veneer subjected to different drying times. For samples dried progressively at 103°C, the best MC prediction model was for the total MC range (0-100%) with an R 2 value of 0.68. However, exposure at 180°C produced surface colour changes, and the CIE L*a*b* colour parameters measuring colour changes were better estimated using the 400-900 nm spectral data than the 1100-2400 nm spectral data. Increased exposure time at 180°C resulted in lower wettability and, hence, larger contact angles, especially when ethylene glycol was used as probe solvent. Lap shear strength tests on veneers showed that adhesion by phenol formaldehyde resins was impaired by the high temperature exposure; however, the lap shear strength test had high variability so there was not always a clear relationship between contact angle and lap shear strength test.

Sensors in the Forest Products Industry

“…Several papers in the current issue use nearinfrared spectroscopy (NIRS) to predict wood properties, including moisture content and basic specific gravity in logs (Hans et al 2015a) and surface quality of aspen veneers (Koumbi-Mounanga et al 2015). NIRS-based hyperspectral images are used to estimate moisture content and density distributions in subalpine fir board (Haddadi et al 2015a, b).…”

Stiffness and moisture content prediction model of wooden veneer using fast online near-infrared (NIR) spectroscopic system

“…Dry veneer stiffness was predicted using NIR spectra by Fujimoto et al 3 from transverse sections of the logs. Prediction of Yellow poplar (Liriodendron tulipifera) veneer stiffness and bulk density using NIR and multivariate calibration was done by Adedipe et al 4 Koumbi-Mounanga et al 5 Examined the surface quality sensing (MC, surface energy characteristics, and adhesive bond strength) of Trembling aspen (Populus tremuloides Michx.) veneers products by NIR spectroscopy.…”