WOOD RESEARCH Volume 68, Number 3, 2023
Uğur Aras

Possibility of Using Crude and Expanded Vermiculite in Cement-Bonded Particleboard Production

The aim of this study is to investigate the effect of using vermiculite on the thermal, physical and mechanical properties of cement-bonded particleboards. For this purpose, single-layer cementitious particle boards with a final density of 1200 kg/m3 and a size of 550 x 550 x 10 mm were produced using 2 type vermiculites (crude and expanded) at three different ratios (5%, 10% and 15%). The produced boards were examined in terms of thermal (TGA/DTG), physical (moisture content, density, water absorption and thickness swelling), mechanical (modulus of rupture, modulus of elasticity, internal bond strength and screw withdrawal resistance) properties. According to the TGA results, using both types of vermiculite caused an increase in cement hydration products in the boards and increased the thermal resistance. While the use of vermiculite did not significant effect on the density and moisture content of the boards, it increased the dimensional stability of the boards. The values of modulus of rupture and modulus of elasticity increased when the low amount of vermiculite was added. However, with the use of vermiculite in the boards, there was a decrease in the internal bond strength and screw withdrawal resistance values in general. All boards produced using vermiculite met the values specified in EN standards.

WOOD RESEARCH Volume 66, Number 3, 2021
Hasan Hüseyin Taş, Bilge Arslan, and Hülya Kalaycıoğlu

Effects of polymer additives on some mechanical and physical properties of cement bonded particleboards

The effects of some polymer additives, also called super plasticizers, on selected physical and mechanical properties of cement bonded particle board were investigated. Two different kinds of poly carboxylic ether (PF300, DX40) and a melamine based polymer (300M) were added to the wood cement mixture. The ratios of polymer additives to the wood cement mixture were 1%, 1.2% and 1.4%. Cement bonded particleboards were manufactured with wood/cement (w/w) ratio of 1:3; target density of 1300 kg.m-3, and CaCl2 content of 5%. The cement bonded particleboards were tested for water absorption (2 and 24 hour), thickness swelling (2 and 24 hour), bending stiffness and strength and internal bond strength. Results of the study showed that most of the polymer addition decreased water absorption and thickness swelling of the boards. Replacement of cement with polymers increased internal bond strength and bending stiffness of the boards while bending strength was slightly reduced. Use of small amount of super plasticizers significantly improves most of the board properties.