Scientists pin down cellulose's molecular weight using new solvent mix
Researchers have validated a method to measure cellulose's molecular weight using a greener solvent combination, potentially replacing a toxic industry standard. The technique works well for large cellulose molecules but struggles with smaller ones, offering limited advantage over existing approaches while costing more to implement.
Originaltitel: Absolute molecular weight distribution of cellulose in DMSO/EmimOAc (1%) with MALS detection
<p>This paper presents a method for the measurement of absolute molecular weight of cellulose using a multi-angle light scattering (MALS) detector in 99% dimethyl sulfoxide/1% 1-Ethyl-3-methylimidazolium acetate (DMSO/EmimOAc). The paper also delivers a suitable dn/dc value for cellulose in this solvent. It discusses the pros and cons of using absolute molecular weight measurements versus traditional column calibration in this solvent. The conclusion is that the dn/dc for cellulose in this solvent is 0.049 ± 0.003 mL/g. Absolute molecular weight measurements in this solvent are somewhat beneficial for celluloses with Mw > 250 kg/mol. However, for low-Mw celluloses (e.g., Avicel), it has severe limitations. Herein, it is confirmed that the DMSO/EmimOAc system can be used to replace the traditional DMAc/LiCl system for cellulose molecular weight analysis of some cellulose materials. However, the former is more costly and time-consuming than the latter.</p>