Abstract
A "green" polymer made by bacteria, xanthan gum has several applications in both the food and drug industries. Because of its harmlessness, xanthan gum is frequently used in other fields after quality improvement through modification. This article describes the grafting process of xanthan gum with styrene and investigates the rheological properties of the modified (grafted) copolymer. For copolymerization, different ratios of xanthan and styrene compositions (XG: St - 1:1.6, 1:5, and 1:8 w/w%) were used. The FTIR spectra of XG-g-St revealed an increase at 1120 cm-1, indicating the formation of additional ether groups due to the St and XG interaction. The rheology properties were investigated at 30, 60, and 80°C. The shear stress of XG dropped from 30 to 80°C, with a maximum shear stress value of 8 Pa at 30°C and a minimum value of 5 Pa at 80°C. According to the findings, grafted with styrene xanthan gum has higher shear stress and better resistance to temperature in comparison with un-modified pure xanthan gum. Due to the grafting new side chains and bonds appear on polymer molecules which affect its viscoelasticity. These findings could be useful in a variety of fields, including oil recovery and construction.