According to the C20 Portland cement concrete (PCC) batching standard, magnesium oxychloride cement concrete (MOCC) is made using bischofite from salt lakes and light-burned magnesium oxide as the main raw materials. In this work, the mechanical properties of MOCC (setting time and compressive and flexural strengths) were tested. The rules governing the phase composition and microstructure changes of the hydration products were analysed using X-ray diffraction and scanning electron microscopy. The results showed that MOCC solidifies rapidly, has high early compressive and flexural strengths and exhibits excellent long-term mechanical properties, far superior to those of the same grade of C20 PCC. The main phase at different curing times was found to be 5Mg(OH)2.MgCl2.8H2O (5.1.8). With hydration from 7 to 365 d, the amount of 5.1.8 fluctuated between 30% and 37% and the microscopic crystal morphology of the MOCC changed significantly. Importantly, fibre-like and rod-like crystals were observed to transform into their respective gel phases from 180 to 270 d. This phenomenon explains the fact that the content of 5.1.8 was the lowest but the mechanical strength of MOCC was the highest at 180 and 270 d. It was also confirmed that 5.1.8 gel is one of the main strength phases.

Seawater from South China Sea was used instead of freshwater to fabricate magnesium oxychloride cement (MOC). To study the basic performance of the seawater-mixed MOC paste, the setting time, hydration exothermic characteristics, compressive strength, thermal stability, seawater resistance, phase composition and microstructure of the paste were analysed in detail. The results showed that the use of seawater in the MOC paste slightly retarded the setting time and increased the total hydration heat. The compressive strength and thermal stability of the seawater-mixed MOC were slightly lower than those of the MOC paste prepared with freshwater. The main hydration product of both MOC pastes was 5Mg(OH)2.MgCl2.8H2O. The residual strength ratio of the seawater MOC paste was 9·70% higher than that of the freshwater MOC paste after 28 d immersion in seawater. However, the standard deviations suggest that the properties of MOC pastes prepared with seawater or freshwater were not significantly different.

Cellulose, as a sustainable biomass material, has aroused wide attention and has been extensively employed in functional biomaterials. However, due to the strong intra/intermolecular interactions, the dissolution problem has significantly limited its applications. Although different kinds of solvents have been developed, most of them still cannot equilibrate dissolution, recyclability, and functional material preparation, simultaneously. In this work, an efficient and recyclable green solventmolten salt hydrate (calcium chloride hexahydrate-lithium chloride, CHLH)was prepared with excellent dissolving ability (high solubility of 7.0 wt %) for cellulose at a low dissolution temperature. Moreover, the CHLH showed good stability and storage properties. The dissolved cellulose could be stored in a solid state at a wide range of temperatures (<65 °C) for more than 3 months while remaining stable. Meanwhile, CHLH exhibited excellent recycling properties. After 5 dissolving–recovering cycles, the recycled CHLH still maintained stable dissolution performance and a high recovery of 92%. More importantly, the advantages of CHLH made the prepared cellulose hydrogel integrate good flexibility, ionic conductivity, and freezing tolerance. When used as a strain sensor, it could not only detect body movements but also identify the motion direction, which would have broad application prospects in flexible electronic devices.