Graft copolymerization has been widely used as a method for modifying the structure of natural polymers, leading to multiple applications in various fields. In this study, the graft copolymerization of acrylic acid (AA) onto guar gum (GG) is followed by multi-detector size exclusion chromatography (SEC) and cross-checked by additional techniques. The effects of various factors such as reaction temperature, initiator concentration, and AA/GG ratio, on the polymer molecular weight, molar dispersity, and on the grafting efficiency are investigated. While the increase in AA concentration leads to a higher amount of polymer formed due to Tromsdorff effect, care has to be taken in choosing the initial parameters and the AA/GG ratio since a higher amount of AA added could lead to a blend of GG-g-AA and polyacrylic acid.Molecular weight distribution (MWD) determined from SEC multi-angle light scattering data and intrinsic viscosity vs. polymer mass illustrate the incorporation of the acrylic acid into the guar gum chains. In the same time, the Mark-Houwink coefficient values from the power-laws used to fit viscosity data allow the efficiency of the grafting process to be quantified.Due to the acrylic acid unique characteristics, it is hoped that the control of the grafting on the guar gum will enhance the polymer applicability.

Synthesis and characterization of guar gum-g-poly(acrylic acid) copolymers

245th National Meeting (2013)

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