Effect of hybrid layered silicates/geopolymer fillers on properties of epoxy composites

Layered silicates are commonly used as filler materials in polymers including thermoset to improve the matrix’s mechanical, physical and barrier properties. Montmorillonite belongs to the class of layered silicates which has great potential as filler due to its high surface area and aspect ratio with thickness of each individual layer is about 1 nm. However, the use of montmorillonite as single filler has limitation in terms of assisting the matrix to achieve high mechanical performance when subjected to various mechanical loads (compression and flexural). Therefore, in this thesis, the use of hybrid fillers was investigated using organo-montmorillonite and geopolymer fillers to obtain epoxy based composite material with greater combination properties. Raw materials geopolymer filler used in this study is from Saudi Arabia. Based on characterization of these minerals resources, it indicates the suitability of being a geopolymer filler. The preparation of the composites and hybrid composites was conducted by mechanical shear mixing method at room temperature. The effect of the organo-montmorillonite and hybrid organo montmorillonite/geopolymer fillers addition on the epoxy was thoroughly studied by compressive and flexural tests, thermal analysis, X-ray diffraction analysis and water absorption test. Epoxy/organo-montmorillonite composite was prepared with varies organo-montmorillonite loading from 1 phr to 7 phr. Results demonstrated that optimum loading of organo-montmorillonite in epoxy was achieved at 3 phr loading. This finding has leads to development of hybrid composites using optimum organo-montmorillonite content and five types of geopolymer fillers (fly ash, kaolin, white clay, pozolonite and silica sand) with loading from 1 phr to 7 phr. However, among five types of geopolymer fillers, kaolin has presented the best compressive and flexural properties at about 36.65 MPa and 20.18 MPa. The data was supported by other analysis such thermogravimetry, X-ray diffraction, and dynamic mechanical analyses. Based on these research outcomes, it can be highlighted that the use of hybrid organo-montmorillonite/geopolymer fillers can more efficiently improve the strength, thermal stability and durability of the epoxy as compared to the single organo-montmorillonite filler. These improvement has led to the exploration of exciting fields and creating novel for the production of hybrid layered silicates/geopolymer filler in epoxy composites.