Hydroxypropyl guar galactomannan (HPGG) properties at solid-liquid interface were studied in this work by investigating adsorption and flocculation behaviors of HPGG with and without borate. Anionic and cationic latex particles were employed to provide the solid-liquid interface. The adsorption densities of HPGG and HPGG/Borate on anionic latex particles surfaces were determined by the difference of HPGG concentrations in solutions before and after adsorption experiments. The adsorption isotherms of HPGG and HPGG/Borate at different conditions were obtained. Hydrophobic interactions were suggested to be the major source of interactions of adsorbed HPGG and anionic latex. According to dynamic light scattering and electrophoretic mobility data, adsorbed HPGG and HPGG/Borate polymer layer on particle surfaces were discussed. The flocculation behavior of HPGG, HPGG/Borate, and HPGG/PBA were compared by studying the residual turbidity change of suspensions added with cationic latex particles. Electrophoretic mobility was used as well to study the electrophoretic behaviors of latex particles covered with HPGG or HPGG/Borate. Flocculation mechanisms of this novel flocculation behavior were discussed in this work. With adding more and more monosaccharide into the flocculation, floes were found to be able to redisperse into the solvent readily. Charge density of HPGG/Borate polymer chain was calculated and the charge density influence on polymer's flocculation behavior was studied. / Thesis / Master of Science (MS)