Probing Interactions in Combined Hydroxide Base Solvents for Improving Dissolution of Cellulose

Abstract

To further understand cellulose-solvent interactions in aqueous hydroxide solutions, cellulose behavior in aqueous solutions of NaOH combined with tetramethylammonium hydroxide (TMAH) or benzyltrimethylammonium hydroxide (Triton B), as well as urea, was investigated. The rheological properties of the solutions were assessed through flow sweeps at different temperatures, and the intermolecular interactions were probed using solvatochromic dyes. The results showed that NaOH combined with TMAH had synergistic effects on cellulose dissolution and was a better solvent for cellulose than the combination of NaOH with Triton B, in spite of the superior dissolution ability of Triton B alone. This somewhat unexpected finding shows that the base pair needs to be selected with care. Interestingly, addition of urea had no significant effect on the solvatochromic parameters or dissolution capacity of solutions of Triton B but rendered improved stability of solutions containing NaOH and/or TMAH. It seems that both urea and Triton B weaken the hydrophobic assembly effect of these solutions, but urea is excluded from interacting with cellulose in the presence of Triton B. This study provides further insight into dissolution of cellulose and the possibility of utilizing combinations of hydroxide bases to achieve improved solution properties.

In situ monitoring of cellulose etherification in solution: probing the impact of solvent composition on the synthesis of 3-allyloxy-2-hydroxypropyl-cellulose in aqueous hydroxide systems

“…after 45 minutes). Taking into account the mentioned observations together with better cellulose solubility in TMAH and Triton B reported in previous works 29,30 better AGE solubility and higher temperature stability of the solutions except for NaOH (Fig. 4), a probable indication could be more occurrence of cascade reaction in NaOH.…”

“…Recently in our group, cellulose dissolution and the existing stabilizing interactions in aqueous solutions of tetramethylammonium hydroxide (TMAH) and benzyltrimethylammonium hydroxide (Triton B) (Scheme 1) as well as their combination with NaOH have been studied. 29,30 The results show that the addition of TMAH and Triton B to NaOH enhances cellulose solubility and in case of TMAH delays the gelation time, allowing for tuning the solution properties by varying the base composition of the solvent. In this study low concentration of the selected bases has been used to dissolve cellulose and later modify it.…”

Investigation of cellulose dissolution in morpholinium-based solvents: impact of solvent structural features on cellulose dissolution

“…No noticeable aggregates could be detected which further conrms the solution stability at different temperatures while applying low to high shear rates. Previous studies on cellulose solutions in NaOH(aq), tetramethylammonium hydroxide (TMAH), benzyltrimethylammonium hydroxide (Triton B) 67 showed that in NaOH cellulose always shows shear thinning behavior indicative of cellulose aggregates existence within the solution. However, when mixed with either TMAH or The shi of the peak at 65.45 to 62.17 ppm in MorOAc/DMSO and 62.74 ppm in MorOH(aq) is suggesting that the "t-g" conformation of the C6-OH group for the crystalline parts of cellulose I had changed into a "g-t" conformation of cellulose II.…”

Bacterial Cellulose Aerogels Derived from Pineapple Peel Waste for the Adsorption of Dyes

“…As a result, these negatively charged functional groups would strongly interact with the positively charged MB species (the dominant form of MB at pH > 6) via the proposed electrostatic interactions (Figure c). It should be noted that the deprotonation was likely insignificant under the applied conditions; therefore, only slight improvements in the MB-trapping efficiency were observed based on the pH increase. , …”

“…It should be noted that the deprotonation was likely insignificant under the applied conditions; therefore, only slight improvements in the MB-trapping efficiency were observed based on the pH increase. 65,66 Varying the initial methylene blue concentration for the adsorption course in the range of 0−400 ppm was also conducted to determine the maximal adsorption capacity of this BC aerogel (Figure 9). The adsorption capacity for MB considerably increased from 4.1 to 29.7 mg/g with growth in the initial concentration of MB from 10 to 200 ppm, respectively.…”