engleski

Synthesis and structural characterization of phosphate-based geopolymers

Geopolymers or inorganic polymers, initially reported by Davidovits, are generally synthesized by exposing aluminosilicate precursor powders to alkaline silicate solution or phosphoric acid solution under ambient or slightly increased temperature. Despite phosphorus geopolymers have been known for almost as long as alkaline geopolymers and despite the properties of phosphate geopolymers such as better acid- resistant, thermal and dielectric behaviour surpass the properties of their alkaline analogues, phosphate geopolymers still have not matched scientific attention and industrial application comparable to their alkaline analogues. One of the reasons is certainly the use of more expensive phosphoric acid compared to alkaline sodium silicate solution. Here we conducted a synthesis and structural characterization (XRD, ATR-FTIR, TG/DTG/DTA) of phosphorus geopolymer derived from metakaolin and phosphoric acid solution, with the aim of high- tech application of phosphorus geopolymers in electronic devices. According to the available literature, the main parameter in reaction for phosphate-based geopolymers is the Al:P atomic ratio with optimal value of 1. Therefore, in this work, atomic ratio Al:P is set to approximately 1 and the water-to-binder ratio, as a measure of workability of geopolymer paste, is set to 0.5.

geopolymers ; silico-aluminophosphate ; metakaolin ; phosphoric acid

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