WOOD RESEARCH Volume 67, Number 5, 2022
Kang Chiang Liew and Yu Feng Tan

Densification and effect of compression ratio on mechanical properties of CLT from low-density timber

The mechanical properties of CLT manufactured from densified low-density planted timber, Paraserianthes falcataria were studied in relation to changes in the area of pores for under densification. Conditioned laminas (MC ≤ 15%) underwent two-stage densification using hot-press machine at 105oC, 6 MPa, for 10 min each, with press released for 1 min 40 sec in between the stages, before cooling (< 100oC) to reduce immediate springback. The laminas with thickness 8 mm, 10 mm, and 15 mm were produced using metal stoppers and further manufactured into three-layered CLT of 24 mm, 30 mm, and 45 mm thick. 20 mm undensified laminas with 60 mm CLT as the control. Results shows that modulus of elasticity (MOE), modulus of rupture (MOR), and compression parallel to grain have improved significantly and showed negative correlation with area of pores, except for compression perpendicular to grain.

WOOD RESEARCH Volume 65, Number 3, 2020
Matej Holc, Igor Karlovits, David Ravnjak, Aleš Palatinus, and Ita Junkar

Influence of gaseous plasma treatment on functional properties of coated papers

Three different types of paper with different coatings have been used in order to study the influence of gaseous plasma treatment on surface properties of paper. Radio frequency (RF) oxygen plasma was used for treatment of papers that contain different parts of organic and inorganic components in their coatings. Surface properties like surface morphology, roughness, surface energy, wettability, and chemistry were studied. The influence of plasma modification was also studied in terms of printability and paper gloss, which are one of the key parameters that dictate the use of such paper in desired applications. The results indicate that plasma modification of different types of coatings indeed influences paper printability as well as gloss function, which was shown to be highly connected with surface morphology, as micro- and nanopores were opened or formed due to selective plasma etching of organic part of the coating. Moreover, significant increase in surface energy was observed on all plasma treated papers, however this seemed not to influence much on the printing and gloss properties.