Cellulose/polycaprolactone blends regenerated from ionic liquid 1-butyl-3-methylimidazolium chloride

Ionic liquid solvent, 1-butyl-3-methylimidazolium chloride (BMIM[Cl]) was used to prepare cellulose/polycaprolactone (PCL) blend films. This solvent was recycled with high yield and purity after blend precipitation. The inter- and intra-molecular hydrogen bonding interactions in these blends were investigated by Fourier transform infrared (FTIR) spectroscopy and it was found that a new peak in the carbonyl region, assigned to hydrogen bonding between carbonyl groups of PCL and hydroxyl groups of cellulose in blends with PCL composition less than 40 wt%. Differential scanning calorimetry (DSC) results implied a partial miscibility of the two components by melting point depression. Moreover, the tensile properties of the blends can be adjusted by incorporating various amounts of PCL into cellulose. The blends show significant enhancement of thermal stability compared to the regenerated cellulose when the content of PCL is higher than 40 wt%. This work demonstrates an effective approach for the processing biodegradable blends from natural and synthetic polymers.