# Magnesium Oxychloride Cement: Development, Opportunities and Challenges
## 9 Application of MOC and Wood as a Composite Building Material  
Wood-cement composites are currently produced in several countries worldwide, primarily in the form of panels, owing to their exceptional exterior characteristics [113]. The primary challenge in the manufacturing of wood-cement composites lies in the chemical incompatibility between cement and wood, with OPC often inhibiting the setting and hardening of cement in most cases [114]. The inhibitory compounds primarily encompass certain sugars, a portion of hemicelluloses, and associated disintegration byproducts. The extent of inhibition is influenced by various factors, including the type of wood species, its geographical origin, the tree part used, the season of wood cutting, cement type, wood-to-cement ratio, and other related factors [115; 116]. Past studies have indicated that, in contrast to OPC, MOC exhibits good compatibility with wood, suggesting its potential as an alternative for OPC in the production of wood-cement boards, particularly for wood species that are poorly compatible with OPC [82; 96; 114; 115].  
Research indicates that wood-MOC composites having an increased wood fiber dosage exhibit reduced thermal conductivity, increased bending resistance, greater residual bending resistance following water immersion and exposure to elevated temperatures, and improved noise reduction properties [82; 96; 114; 117]. Despite an increase in water absorption associated with higher wood fiber dosage, it remains at a relatively low level when mixed with MOC [64]. [PERSON] et al. [96] discovered that integrating rice husk ash into wood-fiber-reinforced MOC improved both the mechanical strength and water resistance of the material, thereby enhancing its environmental sustainability and making it an eco-friendly alternative to traditional resin-based and OPC-based particle boards. Alternative approaches suggest the utilization of MOC and wood via an extrusion process to produce lightweight composite building materials [82]. Simultaneously, MOC can serve as an effective alternative to adhesive solutions employed in wood-based building materials. For instance, [PERSON] et al. [113] suggested that the use of MOC as an inorganic adhesive offers viable and sustainable binding agents for plywood applications. [PERSON] et al. [118] developed an environmentally friendly and high-performance MOC-based formaldehyde-free adhesive containing hybrid combinations of organic-inorganic adhesives, demonstrating that MOC deposited on the surface of fibers formed connections through hydrogen bonds in wood, leading to enhancement in wood-based composites' mechanical characteristics. Furthermore, the incorporation of MOC enhanced the flame-retardant properties of the plywood. [PERSON] et al. [114] demonstrated that greenhouse gas emissions (GHG) related to wood-MOC-based boards containing ISA were around 71% lesser in contrast to plywood manufacture, and similar to the resin-based board. Moreover, the human toxicity of MOC-wood-modified boards was 58% lower in contrast to normal resin-based board manufacture, which involves the use of extremely toxic organic resins. In summary, the above-mentioned studies clearly illustrate that combining MOC with wood for panel production results in reduced GHG emissions, reduced formaldehyde emissions or formaldehyde-free options, and improved product durability with enhanced resistance to decay, fungi, and pests. Therefore, MOC may facilitate the production of sustainable and environmentally friendly wood-based building materials, providing a green construction approach for the next generation.