Role of Sintering Temperature in Production of Nepheline Ceramics-Based Geopolymer with Addition of Ultra-High Molecular Weight Polyethylene

Abstract

The primary motivation of developing ceramic materials using geopolymer method is to minimize the reliance on high sintering temperatures. The ultra-high molecular weight polyethylene (UHMWPE) was added as binder and reinforces the nepheline ceramics based geopolymer. The samples were sintered at 900 °C, 1000 °C, 1100 °C, and 1200 °C to elucidate the influence of sintering on the physical and microstructural properties. The results indicated that a maximum flexural strength of 92 MPa is attainable once the samples are used to be sintered at 1200 °C. It was also determined that the density, porosity, volumetric shrinkage, and water absorption of the samples also affected by the sintering due to the change of microstructure and crystallinity. The IR spectra reveal that the band at around 1400 cm−1 becomes weak, indicating that sodium carbonate decomposed and began to react with the silica and alumina released from gels to form nepheline phases. The sintering process influence in the development of the final microstructure thus improving the properties of the ceramic materials.

Influence of Sintering Temperature of Kaolin, Slag, and Fly Ash Geopolymers on the Microstructure, Phase Analysis, and Electrical Conductivity

“…Upon sintered at 900 °C, the portion of kaolinite phases transformed into semi-crystalline nepheline diffraction peaks. Based on previous studies, nepheline crystals were formed in heated-treated sodium-based geopolymers [ 31 ]. According to Sabbatini et al [ 32 ], the existence of nepheline assisted the improvement of mechanical performance as the result of the favourable amount of silicon-rich and polymerised species.…”

Kinetic study of the transformation of sodalite to nepheline

“…However, this last value is constant (𝐶 = ln[𝐾 0 𝑓(𝑥)]) but it is not independent of the temperature. This value can be calculated by substitution of Equation (7) in 𝐶 = ln[𝐾 0 𝑓(𝑥)]:…”

“…For instance, in recent years, glass–ceramic materials containing nepheline have been documented as efficient UltraViolet Light Emitting Diode (UV‐LED) color converters, 4 scaffolds for bone tissue regeneration 5 or for dental applications 6 . Nepheline is also reported in geopolymers, 7 self‐compacting repair mortars, 8 low thermally conductive ceramic foams, 9 or traditional ceramics 10 . Finally, nepheline can be also prepared through the thermal transformation of zeolites.…”

Correlation Study on the Effect of Sintering Mechanism with the Properties of Geopolymer-Based Ceramic

“…The flexural strength test for the sintered and unsintered geopolymer samples was carried out according to ASTM C-1163b, where the support span was 30 mm long, and the crosshead speed is 0.3 mm/min [15]. The density was calculated, and the water absorption tests were performed following the guidelines outlined in ASTM C642-13 [16].…”