As an eco‐friendly construction material, magnesium oxychloride cement (MOC) has attracted much research interest in recent decades, however, its mechanical properties degrade severely under water attack, which has prevented its wide application in engineering structures. As a widely used mineral waste, fly ash has been applied in civil engineering for decades. The active SiO2 in fly ash is considered to be conductive to improve the water resistance of MOC. In this paper, the influence of fly ash on the mechanical properties of MOC is investigated, especially when subject to water attack. First, the basic mix design of the MOC with a suitable combination of the molar ratios of MgO/MgCl2 and H2O/MgCl2 is developed, and the developed basic MOC mix is modified by adding fly ash to improve its water resistance. Second, the physical and mechanical properties of both the basic MOC and the fly ash modified MOC, such as compressive strength, Young's modulus, flexural strength cured at room temperature, and immersed in water for 28 days at room temperature (25°C) are determined. It is found that the incorporation of fly ash decreases the workability or fluidity, retards the setting time, but improves the compressive strength and water resistance of the MOC. The techniques of X‐ray diffraction, Fourier transform infrared spectroscopy, thermogravimetric analysis/differential scanning calorimetry, scanning electron microscopy, and mercury intrusion porosimetry are applied to the MOC specimens to discover the mechanism by which fly ash affects on the water resistance of MOC. The microscale analysis shows that the addition of fly ash optimizes the pore distribution in MOC resulting in a denser structure, which contributes to the water repellence.

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Disposal of petroleum-based plastics has become a major concern due to its resistance to chemical, physical and biological degradation. As such, the production of an alternative biodegradable material from renewable sources is beneficial. This study aims to produce a polymer blend film, of enhanced formability and durability, from cellulose and chitin, the two most abundant naturally-occurring biodegradable polymers in the environment. Chitin was initially extracted fromPortunus pelagicusshells through demineralization and deproteinization. The crude chitin is of comparable crystallinity with the commercially-available. However, other proteins were speculated to be present as indicated by the extra peaks in the XRD profile. This was then followed by the dissolution of the polymer powders in LiCl/DMAc, blending, casting, forming, cold-pressing and drying. The independent variables considered were cellulose-chitin ratio and the forming time. From the results, samples formed after 24 hours are relatively thinner, softer and more flexible. In addition, the best sample with UTS at 27.36 MPa was that of 80:20 cellulose-chitin, while the worst at 14.79 MPa was that of 20:80 cellulose-chitin both formed after 24 hours. ANOVA revealed that neither the main factors nor the interaction significantly affected the measured values. Lastly, thermal and biological degradation tests showed that the film started to degrade at 308°C and supported 4.9 x 103and 3.8 x 104CFU of mold and bacteria, respectively.