Thermal and spectroscopic analyses of guar gum degradation submitted to turbulent flow.

In this paper, a 400 ppm aqueous solution of guar gum polysaccharide was submitted to a turbulent flow regime in order to monitor molecular degradation and drag reduction. Guar gum samples were isolated and analyzed by spectroscopic, thermoanalytical and viscosimetric techniques. The drag reduction promoted by guar gum is compromised as the polysaccharide undergoes degradation. Viscosimetric analysis of guar gum showed a reduction in viscous molecular mass. Mid-infrared spectra and hydrogen nuclear magnetic resonance suggest that mechanical degradation promotes hydrolysis of the glycosidic bond α (1 → 6) releasing (d)-galactose owing to the appearance of the carbonyl functional group. Thermal analysis revealed the reduction of the polysaccharide's thermal stability by reduction of the polymer chain. A comprehensive analysis of these combined parameters affords a foundation for the development of more efficient biopolymers in the context of improved drag reduction.

Study of the mechanical degradation mechanism of guar gum in turbulent flow by FTIR.

Guar gum is used in low concentrations as a drag reducing agent in turbulent flows to significantly accelerate flow in oil pipelines, oil well operations and aqueous systems. Drag reduction also promotes a decrease in energy demand in pumping systems. However, the polymers undergo mechanical degradation and lose the ability to promote drag reduction over time. In this paper, the drag reduction, the power required by the pumps and the degradation of the guar gum were evaluated during a turbulent flow of an aqueous solution containing the biopolymer. The results indicate the mechanism of degradation of guar gum by the hydrolysis of the bond α (1 → 6), liberating the galactose, which justice to the loss of efficiency throughout the process. An understanding of this mechanism should allow for the development of more mechanically resistant polymers and the increase of drag reduction capacity over time.