The optimum level of nano-wollastonite consumption as fire-retardant in poplar wood (Populus nigra)

Authors

• A. Haghighi Poshtiri ¹
• H. R. Taghiyari ²
• A. Naghi Karimi ³

1. Wood and Paper Sciences and Technology Dept., Faculty of Natural Resources, University of Tehran, Iran.
2. Wood Science and Technology Department, The Faculty of Civil Engineering, Shahid Rajaee Teacher Training University, Tehran, Iran.
3. Institute of Tropical Forestry & Forest products (INTROP), University Putra Malaysia (UPM) & Dept. of Wood Science & Technology, Faculty of Natural Resources, The University of Tehran, Iran.

Abstract

Fire-retarding properties of wollastonite nanofibers in poplar wood (Populus nigra) were studied here. Some physical properties such as water absorption, volumetric swelling and anti-swelling efficiency (ASE) were also measured. Specimens were prepared according to the ISO 11925 specifications for the fire-retarding properties and according to the ASTM D4446 -2002 specifications for the physical properties. Impregnation of wood specimens with nanowollastonite was carried out at consumption levels of 4, 6.3, 10 and 12%, using Rueping Method (empty-cell process) and compared with the control specimens. Five fire-retarding properties were measured, including weight loss (%), ignition point (s), fire endurance (s), glow endurance (s) and carbonization area (%). The obtained results indicated that fire-retarding properties were significantly improved in the NW-treated specimens. Furthermore, the NW-impregnated specimens gained higher dimensional stability. However, water absorption increased. Heat-conductivity of wollastonite limited accumulation of heat at one spot, furthermore, it acted as a physical barrier to deter heat and mass transfer between the gas and the condensed phase, consequently, fire-retarding properties were improved.

Keywords

• water absorption
• anti-swelling efficiency
• Poplar wood
• Minerals
• Nano-wollastonite
• Rueping method
• Fire-Retarding Properties