Development of kaolin geopolymer ceramic with addition of ultra high molecular weight polyethylene (UHMWPE) as binder for lightweight ceramics

Abstract

A lightweight ceramic material displays physical, mechanical and structural features which is highly preferred in modern ceramic industry. Geopolymer technology has been involved in many applications including in the formation of ceramic. The transformation phase of geopolymer from amorphous to crystalline upon heating require a low processing temperature compared to the conventional ceramics. A major synthetic process for industrialised lightweight ceramics is to use additives which are organic in nature such as binders, plasticizers, surfactants and lubricants.This study investigated the use of geopolymer in producing ceramic materials where kaolin was used as main source material and Ultra High Molecular Weight Polyethylene was added as binder. In this study, the solid-to-liquid ratio of 1.0 and alkaline activator ratio of 0.24 were fixed. Kaolin geopolymer were then cured at 80 °C for 24 hours, the samples were then crushed into powder form. By using powder metallurgy method in producing kaolin geopolymer ceramic, three parameters used are sintering temperature (900 °C, 1000 °C, 1100 °C, 1200 °C), binder content (2 wt.%, 4 wt.%, 6 wt.%, 8 wt.%) and sintering method which are conventional and two-steps sintering method. The optimum weight percent of binder were studied by fixing the sintering temperature, while the optimum of sintering temperature were studied by fixing the weight percent of binder based on testing of flexural strength, density, shrinkage, and water absorption. The results indicated that kaolin geopolymer ceramic with the addition of 4 wt.% of Ultra High Molecular Weight Polyethylene sintered at 1200 °C using two steps sintering method could achieve an optimum strength of 94.32 MPa with a density of 1.71 g/cm3. Also a smooth surface and increasing in formation of pores were observed, which would facilitate the formation of the lightweight and strong structure. Then, the performance of kaolin geopolymer lightweight ceramic was examined by performing microstructural and mechanical properties tests. The outcomes revealed the possibility to produce a lightweight ceramic based kaolin-geopolymer with a considerable characteristics and mechanical properties, which could open the door for many applications in the future. Geopolymer based lightweight ceramic has been claimed as a promising material, due to its ability to produce a high-performance lightweight ceramic and because of its relevant environmental and economic benefits. Furthermore, lower-powered mechanical and thermal treatments are required to ensure the excellent properties and quality to produce the lightweight ceramic materials lead to a positive effect on the environment hence suitable with the desire for eco-friendly industry.