Influence of sodium dodecyl sulphate on the surface and rheological behaviour of functionalised silica/polyacrylamide for drilling

The stability of polymer composite can be enhanced by altering the structure of the functionalised material with surface modifiers, such as silane coupling agents, organic modifiers, surfactants and others. Surfactant has emerged as a potential modifier since it is eco-friendly and simple. In this study, the surface of functionalised silica (SiO₂) was modified using sodium dodecyl sulphate (SDS) in a polyacrylamide (PAM) composite. Characterisation of the drilling fluid was examined through Fourier-transform infrared spectroscopy, surface tension, contact angle and rheological tests. According to the results, FTIR proved that the modification of PAM was successful. However, all modified PAM showed more hydrophilic properties with low surface tension than bare PAM. The rheological properties of all the modified PAM were varied over all the concentrations of SDS. Meanwhile, the rheological properties of the modified PAM were better than that of bare PAM. Due to the synergistic effect between the surfactant and functionalised material involved, the drilling fluid achieved low plastic viscosity in modified PAM. With a flat gel strength and better rheological properties, 0.2 wt% SDS in modified PAM is a great and promising formula in this study. In the future, further investigation can be conducted on bored pile drilling using this formulation.