Tetramethylguanidine-based gels and colloids of cellulose

Abstract

Novel and stable gels of cellulose were produced. These gels are prepared at room temperature by combination of cellulose and tetramethylguanidine (TMG) in different ratios (1:1, 1:2, 1:3 in equivalents of alcohol groups of cellulose per number of molecules of TMG). Detailed NMR, SEM, rheological and XRD studies of these gels were carried out. The concentration of cellulose in the gel, temperature, frequency of oscillation and shear rate were used as variables in order to understand the fundamentals and optimize operational conditions, considering their possible use as matrices for CO₂ capture. Cellulose recovery from a specific gel was performed using ethanol as precipitating agent, leading to a lower crystallinity, which permits to consider this polymer in further studies associated to physical/chemical modification of cellulose.

Keywords: Cellulose; Colloids; Gels; Molecular interactions; NMR; Rheology.