MINERAL POLYMER: CURRENT DEVELOPMENTS AND PROSPECTS
MINERAL POLYMER: CURRENT DEVELOPMENTS AND PROSPECTS
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作者：
Ma Hong-wen
Geopolymer (or mineral polymer) is a new category of inorganic nonmetal materials, which is manufactured mainly from various aluminosilicate minerals or industrial solid wastes, with metakaolin as ingredient, liquid sodium silicate as structural template, and sodium and/or potassium hydroxide solution as activator. Four stages are included in the formation process of mineral polymers, i.e., solution of aluminum and silicon from solid particles, and complex in the liquid; diffusion from the particle surface into interstitial space; concentrating and polymerization of the components by chemical reaction to form interstitial aluminosilicate gel; and removal of extra water and solidification of the gel phase. The matrix phase so formed in geopolymer is similar to zeolite in chemical composition, possibly being an analogue of opal in microstructure, and a three dimensional network in physical framework to encapsulate the insoluble solid particles, which is a structural foundation for geopolymeric materials with excellent mechanical performance and chemical stability. The properties of geopolymer vary obviously with component concentrations in the system and the dynamic process of geopolymerization; especially compressive strength is developing paradoxically with solidifying time. Understanding how each component in a system and the solidifying condition influence aluminosilicate polymerization is eagerly needed for establishing a physical model to characterize phase component, structure, and properties of geopolymer, which is a theoretical foundation for designing the materials, and also a key for the technique to manufacture geopolymeric materials from industrial solid wastes by aluminosilicate polymerization.
