Thermal behavior of cellulose diacetate melt using ionic liquids as plasticizers

Abstract

1-Butyl-3-methylimidazolium tetrafluoroborate ([BMIM]BF₄) was chosen as a plasticizer for cellulose diacetate (CDA) to investigate the feasibility of CDA melt spinning. [BMIM]BF₄/CDA was characterized by Fourier transform infrared (FTIR) spectroscopy, dynamic thermomechanical analysis (TG), the degree of crystallinity (XRD), scanning electron microscopy (SEM) and the thermal stability of CDA. The rheological properties of [BMIM]BF₄/CDA were investigated by a rotary rheometer and the zero-shear viscosity was predicted by the three-parameter Carreau viscosity model from apparent viscosity data. The [BMIM]BF₄/CDA melt showed a shear-thinning behaviour. The melt with higher CDA concentrations and higher shear rates was found to be sensitive to temperature; thus, we could adjust the processing technology by changing the temperature and shear rate. However, the structural viscosity index of the melt decreased with increase in the [BMIM]BF₄ content and went up after a decline with temperature increase.