Using Wollastonite Nanomaterials in Gypsum-Wood Composites

In this study, the effect of wollastonite on mechanical, physical, and morphological properties of composites made of sesame stem (Sesamum indicum L.) and gypsum was investigated. The mixing ratio of sesame stem as a lignocellulosic material with gypsum at three levels (10:90, 20:80, and 30:70) and wollastonite at three levels (0%, 5%, and 10%, based on dry weight of cement) were considered as the variables. Fire resistance (weight loss) was tested according to ISO 11925-3 and DIN EN 634-1 and two specifications for the mechanical and physical properties. Microstructural properties of composites were evaluated by scanning electron microscopic (SEM) imaging. The results showed that boards containing wollastonite increased the physical and mechanical properties compared with gypsum board without wollastonite. The modulus of rupture, modulus of elasticity, and internal bonding of the boards decreased with increased sesame stemcontent, and its maximum value was obtained when using 10% sesame stem. The addition of 10% wollastonite is recommended to significantly improve the fire retardancy of the boards. The results from SEM images showed that the wollastonite can fill in the gaps inside the boards and create a solid structure.