Biopolymer-assisted stable halloysite nanotubes dispersion in alkaline environment and their application in cementitious composite

The colloidal dispersion of biopolymer-treated HNTs in the cementitious environment was studied. Three different biopolymer treatments, namely casein (C), guar gum (GG), and xanthan gum (XG), were utilized to prepare the stable colloidal dispersions of HNTs in such environments. The examination of the dispersion and time-dependent stability of untreated HNTs in a synthetic pore solution (SPS) revealed rapid agglomeration and settling of the particles. Specifically, the stabilization of XG-treated HNTs was superior compared to those treated with GG and C biopolymers. XG-treated HNT suspension in the pH 13 environment existed as monodisperse nanoparticles centered around 20 nm, while bare HNTs existed as polydisperse across 200 nm to 7000 nm. Moreover, XG-treated HNTs boosted cement mortar samples, increasing compressive strength by 29.4 % and reducing initial and final water absorption by 15.8 % and 19.9 %, respectively, after 90 days. Furthermore, the microstructural morphology of the HNT-XG-modified mortar exhibited improved compactness and homogeneity.