Geopolymer

A geopolymer is an <a href="/facts/Inorganic_compound/TfFfzxSz">inorganic</a>, often <a href="/facts/Ceramic/9JKudpqX">ceramic</a>-like material, that forms a stable, <a href="/facts/Covalent_bond/EzMLf3Pz">covalently bonded</a>, <a href="/facts/Non-crystalline_solid/YTIzmrR0">non-crystalline</a> to <a href="/facts/Crystallization_of_polymers/hLNR2u5c">semi-crystalline</a> network through the reaction of aluminosilicate materials with an alkaline or acidic solution. Many geopolymers may also be classified as alkali-activated cements or acid-activated binders. They are mainly produced by a chemical reaction between a chemically reactive <a href="/facts/Aluminosilicate/3gclsh2j">aluminosilicate</a> powder e.g. <a href="/facts/Metakaolin/kvhtn5LG">metakaolin</a> or other clay-derived powders, natural <a href="/facts/Pozzolan/hYvjy2vQ">pozzolan</a>, or suitable glasses, and an aqueous solution (<a href="/facts/Alkaline/s6NqPGSP">alkaline</a> or <a href="/facts/Acidic/FySU18n1">acidic</a>) that causes this powder to react and re-form into a solid monolith. The most common pathway to produce geopolymers is by the reaction of metakaolin with <a href="/facts/Sodium_silicate/055T0IYW">sodium silicate</a>, which is an alkaline solution, but other processes are also possible.
The term geopolymer was coined by <a href="/facts/Joseph_Davidovits/j4u6tcfQ">Joseph Davidovits</a> in 1978 due to the rock-forming minerals of geological origin used in the synthesis process. These materials and associated terminology were popularized over the following decades via his work with the Institut Géopolymère (Geopolymer Institute).
Geopolymers are synthesized in one of two conditions:

<ul><li>in <a href="/facts/Alkaline/s6NqPGSP">alkaline</a> medium (Na+, K+, Li+, Cs+, Ca2+…)</li>
<li>in <a href="/facts/Acid/FySU18n1">acidic</a> medium (<a href="/facts/Phosphoric_acid/l6NbwyCv">phosphoric acid</a>: H3PO4)</li></ul>
The alkaline route is the most important in terms of research and development and commercial applications. Details on the acidic route have also been published.
Commercially produced geopolymers may be used for fire- and heat-resistant coatings and adhesives, medicinal applications, high-temperature ceramics, new binders for fire-resistant fiber composites, toxic and <a href="/facts/Radioactive_waste/MjYh5tlu">radioactive waste</a> encapsulation, and as cementing components in making or repairing concretes. Due to the increasing demand for low-emission building materials, geopolymer technology is being developed as a lower-CO₂ alternative to traditional Portland cement, with the potential for widespread use in concrete production. The properties and uses of geopolymers are being explored in many scientific and industrial disciplines such as modern <a href="/facts/Inorganic_chemistry/ErD6ypnb">inorganic chemistry</a>, <a href="/facts/Physical_chemistry/WqwnJjRM">physical chemistry</a>, <a href="/facts/Colloid_chemistry/9EVucqND">colloid chemistry</a>, <a href="/facts/Mineralogy/MeIK9lx9">mineralogy</a>, <a href="/facts/Geology/WGvVRIYF">geology</a>, and in other types of engineering process technologies. In addition to their use in construction, geopolymers are utilized in resins, coatings, and adhesives for aerospace, automotive, and protective applications.

Geopolymer open-in-new

Geopolymer