KE Yuman, WU Yi, XU Mengxue, HE Yan, CUI Xuemin
(Guangxi Key Lab of Petrochemical Resource Processing and Process Intensification Technology, School of Chemistry and
Chemical Engineering, Guangxi University, Nanning 530004, Guangxi, China)

Abstract: Geopolymer composite materials were prepared by mixing evenly according to the formula molar ratio (SiO₂/Na₂O = 1.3, Na₂O/Al₂O₃ = 0.8, SiO₂/Al₂O₃ = 2.96, and H₂O/Na₂O = 18) with metakaolin and water as raw materials, industrial water glass as alkali activator, and different amounts of PEG as additives. After mechanical stirring, the geopolymer slurry was cast in a cube mould with the side length of 20 mm, cured at 60 °C for 24 h and then demoulded. Based on the compressive strength and elastic modulus of the composites as the norms, the samples were analyzed by scanning electron microscopy (SEM), X - ray diffraction (XRD), and universal electronic testing machine. The results showed that adding different amounts of PEG-4000 could improve the strength and toughness of the geopolymer, and the brittleness could also be improved. The compressive strength of the composite materials increased first and then decreased with the increase of the PEG-4000 amount while the elastic modulus of the composites decreased only. The addition of PEG did not affect the stability of the phase of the geopolymer.

Key words: geopolymer; PEG-4000; compressive strength; elastic modulus