氯氧镁胶凝材料结合秸杆纤维的适应性与改性研究

Due to the corrosion susceptibility of straw fiber in alkaline environment and the problems of durability of straw fiber combined with modern inorganic cementing materials, the strategy for systematically investigations of the compatibility of straw fiber in different alkaline inorganic cementing systems are proposed, including both short-term and long-term effects. Focus on the weak alkaline character of the Magnesium Oxychloride Cement (MOC) and its poor water resistance property, an innovative method by mixing the straw, phosphoric/ploymer and MOC will be applied to modify the composite cement systems. The compatibility of the straw fiber in MOC systems and interaction mechanisms and the properties of the afforded MOC composite cement systems will be investigated based on the detections of the corrosion behaviors of different alkaline conditions toward the straw fiber, and the detection and characterization of structures and properties of the interface between straw fiber and MOC. The combination effects and mechanisms of [PO4]3- with its hydration products and polymers will be investigated through a list of tests for the crystalline surface of the hydration products of phosphoric acid-polymer-MOC, such as chemical elements/components, composition of the crystalline surface, chemical groups, electrical properties, and the detection and characterization of the morphology of polymer films and the interaction styles of the films with other phases. Further more, the morphology and formation of the complex water-proof structures and the water-resistance mechanisms will be probed. The ultimate objective of the project is providing a new direction and theoretical basis for the effective improving for the water resistance of MOC and the exploit and application for high performance straw fiber/magnesium oxychloride cement composite materials.

针对秸杆纤维易受碱性环境腐蚀以及与无机胶凝材料结合存在的耐久性问题，提出系统研究秸杆纤维在不同碱性无机胶凝体系中的短期与长期适应性的路线。基于氯氧镁胶凝材料弱碱特性及耐水性差的关键问题，提出利用氯氧镁胶凝材料结合秸杆纤维和磷酸/聚合物复合改性胶凝材料耐水性能的新方法。通过不同碱性环境对秸杆纤维的侵蚀效应以及秸杆纤维/氯氧镁胶凝材料界面结构与性能的测定和表征，探索氯氧镁胶凝材料结合秸杆纤维的适应性以及结合机理与性能。通过磷酸-聚合物-氯氧镁胶凝材料复合体系水化产物晶相表面化学元素、成分、相组成、基团、电性能、聚合物膜形貌及界面结合状态的测试与表征，研究磷酸（ [PO4]3-）与聚合物及水化产物的作用和结合机理，探索复合耐水结构的形态、形成及耐水机理。为氯氧镁胶凝材料耐水性能有效改善和高性能秸杆纤维/氯氧镁胶凝复合材料的开发与应用提供新的方向和理论支撑。

项目研究围绕无机胶凝材料与秸秆纤维的适应性问题，系统研究和探索了不同碱性环境对秸秆的侵蚀效应与作用机理，秸秆纤维在不同碱性无机胶凝体系中的短期与长期的稳定性与耐久性。研究了秸秆纤维对无机胶凝材料水化、硬化、物理和力学性能影响，秸秆纤维与无机胶凝材料界面结合性能、结合状态与结合机理，为结合秸秆纤维的无机胶凝材料的选择和性能改善提供理论依据和技术支撑。基于氯氧镁胶凝材料与秸秆结合良好的适应性，针对氯氧镁胶凝材料耐水性差的关键问题，重点开展了磷酸/聚合物复合改性氯氧镁胶凝材料耐水机理与性能研究，研究磷酸与水化产物、磷酸与聚合物的相互作用与结合形态，探索磷酸盐/聚合物复合耐水结构的存在、形成规律及影响因素。研究结果表明磷酸和聚合物复合改性可使得试件耐水系数达到0.99。研究揭示了磷酸在复合耐水结构形成中的关键作用，获得最佳改性效果与路径，为广泛利用秸秆资源，开发高性能秸秆/无机胶凝复合材料提供理论及技术支撑。