Geopolymer Resins and Binders
They comprise:
- Metakaolin MK-750-based geopolymer binder
- chemical formula (Na,K)-(Si-O-Al-O-Si-O-), ratio Si:Al=2 (range 1.5 to 2.5)
- Silica-based geopolymer binder
- chemical formula (Na,K)-n(Si-O-)-(Si-O-Al-), ratio Si:Al>20 (range 15 to 40).
- Sol-gel-based geopolymer binder (synthetic MK-750)
- chemical formula (Na,K)-(Si-O-Al-O-Si-O-), ratio Si:Al=2
The first geopolymer resin was described in a French patent application filed by J. Davidovits in 1979. The American patent, US 4,349,386, was granted on Sept. 14, 1982 with the title Mineral Polymers and methods of making them. It essentially involved the geopolymerization of alkaline soluble silicate with calcined kaolinitic clay (later coined metakaolin MK-750 to pinpoint on the temperature of calcination, namely 750 °C). In 1985, Kenneth MacKenzie and his team from New-Zealand, discovered the Al(V) coordination of calcined kaolinite (MK-750). This had a great input towards a better understanding of its geopolymeric reactivity.
Since 1979, a variety of resins, binders and grouts were developed by the chemical industry, worldwide.
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