What is a geopolymer? Introduction

Geopolymers are chains or networks of mineral molecules linked with co-valent bonds. They comprise following molecular units (or chemical groups):

-Si-O-Si-O- siloxo, poly(siloxo)
-Si-O-Al-O- sialate, poly(sialate)
-Si-O-Al-O-Si-O- sialate-siloxo, poly(sialate-siloxo)
-Si-O-Al-O-Si-O-Si-O- sialate-disiloxo, poly(sialate-disiloxo)
-P-O-P-O- phosphate, poly(phosphate)
-P-O-Si-O-P-O- phospho-siloxo, poly(phospho-siloxo)
-P-O-Si-O-Al-O-P-O- phospho-sialate, poly(phospho-sialate)
-(R)-Si-O-Si-O-(R) organo-siloxo, poly-silicone

Geopolymers are presently developed and applied in 9 main classes of materials:

• Waterglass-based geopolymer, poly(siloxonate), soluble silicate, Si:Al=1:0
• Kaolinite / Hydrosodalite-based geopolymer, poly(sialate) Si:Al=1:1
• Metakaolin MK-750-based geopolymer, poly(sialate-siloxo) Si:Al=2:1
• Calcium-based geopolymer, (Ca, K, Na)-sialate, Si:Al=1, 2, 3
• Rock-based geopolymer, poly(sialate-multisiloxo) 1< Si:Al<5
• Silica-based geopolymer, sialate link and siloxo link in poly(siloxonate) Si:Al>5
• Fly ash-based geopolymer
• Phosphate-based geopolymer
• Organic-mineral geopolymer

Joseph Davidovits, the inventor and developer of geopolymerization, coined the term “geopolymer” in 1978 to classify the newly discovered geosynthesis that produces inorganic polymeric materials now used for a number of industrial applications. If you want updated information, get the recently published book Geopolymer Chemistry & Applications. Go to the Geopolymer Shop. You may also go to the Geopolymer Library and download several papers.