385285 Microstructure Characterization of Magnesium Oxide-Based Wallboard Composites for Enhanced Structural Properties and Fire/Water Resistance
Despite being used on a large scale since antiquity in ancient China, magnesium oxide (MgO) building products are not used in the United States. This largely stems from the inability of prior manufacturers, primarily Chinese based, to produce consistent and quality materials that meet quality control requirements for US building standards. MgO building products have the potential to displace current products simply based on their superior properties that can be achieved with strict production quality control. The focus of this work is a collaboration between JetProducts LLC and Clemson University to develop correlations between the MgO cement molecular / nanoscale properties (crystalline structure, composition, microstructure) and the macroscale properties (strength, flexibility, and fire/moisture barrier properties), which are significantly influenced by the manufacture parameters(raw material, additives, and curing process).
Current residential and commercial construction materials are dominated by oriented strand board (OSB), plywood, gypsum board (sheetrock), and Portland cement-based boards. Each of these options has significant drawbacks from a sustainability standpoint. OSB and plywood are moisture impermeable, highly flammable, and contain toxic formaldehyde-based resins. Sheetrock and Portland cement-based materials are not water resistant and have a very high CO2 footprint, unless they contain a high fraction of fly ash, which then imparts potential toxicity issues due to the significant heavy metal contamination. Furthermore, the presence of crystalline silica in these materials can lead to occupational Silicosis. MgO construction materials have significant potential in the US residential and commercial markets with answers to fire resistance, contractor health/safety issues and manufacturing carbon footprint concerns. JetProducts is a startup small business that began in 2005 and has become a primary producer of MgO-based construction materials in the US, which is a rapidly expanding market. This work has the potential to transform the building products industry by providing a fundamental understanding of the underlying phenomena that influence the properties of MgO cement boards, which will enable the broad emergence of a greener and more sustainable product line.
In this project, we have obtained several wallboard samples of varying compositions and cured under different conditions to impart a range of mechanical properties. We also obtained samples from Chinese manufacturers for comparison. We have characterized these material using x-ray diffraction, thermal analysis, energy-dispersive X-ray spectroscopy, and high-resolution environmental SEM. Based on these results, we can draw correlations that connect the macroscale mechanical properties with the material chemical composition, MgO crystalline phase, grain size, and composite morphology.