engleski

Preparation of geopolymer biocomposites

Geopolymers are novel materials made up of aluminosilicate precursors mixed with alkali activation solutions. Common solid precursors are class F fly ash, metakaolin and blast furnace slags, with the main requirement of calcium content not exceeding 10 %. Fly ash and blast furnace slags are waste materials which get reused in these kinds of materials, while metakaolin is kaolin dehydroxylated at temperatures ranging between 500 and 800 °C. Biocomposites are composite materials which utilize natural materials (fibres or particles) as one or more of its components. In this work the preparation of biocomposite based on geopolymer as binder/matrix and almond and hazelnut shell as particle filler was conducted. The influence of NaOH solution pretreatment of nutshell was determined by Fourier transform infrared spectroscopy (FTIR) and scanning electron microscopy (SEM). Thermal properties of prepared composites and its components were analyzed by simultaneous differential thermal and thermogravimetric analysis (DTA/TGA). Optimal solid precursor and activation solution mass ratio was determined as 1.2, and binder and nutshell mass ratio as 1. FTIR and SEM analyses show changes in the pretreated nutshell composition and morphology. The thermal analysis of composites and its components shows typical results for such materials. Further research of different pretreatments, curing conditions and composite components is required for obtaining a proper and applicable material.

Geopolymers ; Biocomposites ; Fiber Pretreatment

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