WOOD RESEARCH Volume 69, Number 1, 2024
SEOK-UN JO, HAK-BYUNG CHAE, HEE-JUN PARK, and EUN-SUK JANG

THE OPTIMAL IMPREGNATION AMOUNTS OF FLAME-RETARDANT FOR KOREAN LARCH AND JAPANESE CEDAR BUILDING MATERIALS

In Korea, in accordance with regulations MOLIT notice 2023-24 regarding the flame retardant performance of building finishing materials and fire spread prevention structure, it is mandated that flame-retardant materials have a total heat emission less than 8 MJ/m2. Consequently, our study aimed to determine the quantity of flame-retardant treatment required to meet MOLIT notice 2023-24 for Korean larch and Japanese cedar, as commonly used exterior materials in construction. To this end, we investigated using a cone calorimeter to observe changes in the THR (total heat released) depending on the SCFI (solid content of flame-retardant impregnation). Our simple linear regression analysis indicated that the SCFI needed to satisfy the prescribed flame-retardant standard of 8 MJ/m2 was 93.9 kg/m3 for Korean larch and 144.6 kg/m3 for Japanese cedar. As a result, we established optimal impregnation levels of flame retardant for both species

WOOD RESEARCH Volume 68, Number 3, 2023
Yoshikazu Mori, Mio Nakajima, Akihiro Ishida, Noboru Ito, Yohei Kurata, Kazumasa Shimizu, Yoshihiro Katayama, Makoto Kiguchi, Kana Yamashita, Takeshi Fujiwara, and Mario Tonosaki

Changes in Hemicellulose Structure Associated with the Transition from Earlywood to Latewood at Juvenile Wood in Cryptomeria Japonica

The chemical composition and variations in chemical structure of hemicellulose in earlywood (EW) and latewood (LW) of two individual Japanese cedar trees (C-Boka and T-Boka) were investigated. The trees were cultivated under different growth conditions: C-Boka grew slowly in a forest, while T-Boka grew rapidly in a location rich in nutrients and sunshine. For the chemical structure of hemicellulose, arabinoglucuronoxylan (AGX) showed varied side-chain substitution rates with glucuronic acid and different molecular weights in the transition between EW and LW. In contrast, the fundamental composition of glucomannan/galactoglucomannan (GM/GGM) was relatively unchanged between EW and LW. The modification of AGX and GM/GGM from EW to LW differed between C-Boka and T-Boka and might be influenced by the growth rate of the trees.