Preparation and characterisation of methylcelluloses from Miscanthus sinensis

Methylcelluloses were prepared and characterised from Miscanthus sinensis (elephant grass). M. sinensis pulps were prepared by impregnation rapid steam pulping process (IRSP) and bleached by a total chloride free (TCF) sequence using hydrogen peroxide. Aldrich α-cellulose was used as a model material to find a suitable methylation method for bleached pulps. The methylcelluloses were synthesised via double methylation with iodomethane in isopropanol slurry at 60 °C for 22 h. The supramolecular substitution patterns were determined by 13C nuclear magnetic resonance (NMR) spectroscopy and the intrinsic viscosities were measured in 4% NaOH solution. The rheological properties were measured in either dimethyl sulphoxide (DMSO) or 4% NaOH solution and were similar to commercial methylcelluloses in distilled water. Water-soluble and alkali-soluble methylcellulose yields were determined by solvent extraction. This investigation helped to find the proper conditions for methylating bleached pulps prepared from M. sinensis and showed that high-quality methylcelluloses can be prepared from M. sinensis.