Preparation and characterization of high-strength and water-resistant waterborne epoxy resin/magnesium oxychloride composite based on cross-linked network structure

To expand the application of magnesium oxychloride cement (MOC) as a kind of engineering materials in the construction field, organic–inorganic hybrid modifications were performed. Waterborne epoxy resin/magnesium oxychloride composites (WER/MOC) with high-strength and water-resistance were prepared using a simple and green method with MOC as matrix and WER as reinforcement. The effects of WER on the resulting composite’s viscosity, mechanical strength, water resistance, phase composition, thermal stability, and micromorphology were discussed. The results demonstrated that WER reduced the viscosity of the WER/MOC complex system, and the composite water resistance and compressive strength were improved, which were mainly attributed to chemical reactions between WER and MOC to form a crosslinked network structure. Meanwhile, XRD analysis results showed that the intensity of the diffraction peak of the 3-phase decreased and 5-phase increased with WER addition to the composite and no new crystal phase appeared. The compressive strength, water resistance, thermal stability, and porosity of these WER/MOC composites reached the best values when the WER mass proportion was 4.8%. Here, the composite water absorption rate decreased to 8.7%, softening coefficient increased to 17.8%, middle compressive strength (sealed for 7 d) at 48.0 MPa, and dry bulk density increased to 1.34 g/cm3. Thus, these WER/MOC composites were suitable for use as engineering materials in the construction and road industries.