Abstract: An industrial waste lignin was modified by esterification using acetic acid. The modified lignin (ML) was blended upto 50 wt% with cellulose acetate. The blends were prepared by solution blending method. The thermal properties and miscibility of cellulose acetate (CA) and modified lignin (ML) blends were investigated by thermo gravimetric analysis (TGA), differential scanning calorimetry (DSC), scanning electron microscopy (SEM) and Fourier transform infra-red spectroscopy (FTIR) over the entire range of composition. Although the modified lignin shifts the onset of CA decomposition to lower temperatures, the CA/ML blends are thermally more stable than CA over the wider temperature range. The TGA results suggest all blends are compatible. These results correlate well with the glass transition temperature (Tg) data where single Tg has been obtained for all these blends. There is a slight decrease in Tg as the lignin wt% increase in blends, where in (70/30) composition shows higher value than CA. No phase separation was found in SEM images of blends. The FTIR analysis revealed the formation of blending between cellulose acetate and modified lignin.
Keywords: Cellulose acetate, Modified lignin, Thermal stability, DSC, SEM, FTIR.