Molecular structure and dielectric properties of some treated lignins

The infrared absorption spectra of rice straw soda lignin (RSL), cotton sta lk soda lignin (CSL) and lignosulphonate (LS) were studied in the region (2 00-4000 cm(-1)). The structures of the RSL treated with different concentra tions of H2O2 and sulphuric acid were analysed spectrophotometrically. The dielectric properties of the investigated samples were measured in the freq uency range 10(2)-10(5) Hz and temperature range 20-120 degrees C. The diel ectric constant <(epsilon)over bar>, dielectric loss <(epsilon)over bar> an d tan delta were measured and are discussed on the basis of the molecular s tructure obtained from IR spectra. (C) 1998 Elsevier Science Limited. All r ights reserved.