Chemical Structure and Thermochemical Property of Lignin Sulfonate

Calcium lignosulfonate( Ca-Ls) was selected as the raw material. Its chemical structure and property were characterized by means of elemental analysis and Fourier transform infrared spectroscopy( FT-IR). The pyrolysis characteristics were also analyzed by thermal gravimetric analysis( TG) and pyrolysis-gas chromatography combined with mass spectrometry( Py-GC/MS). The results showed that: 1) Ca-Ls had a lower carbon and nitrogen content and higher sulfur content than lignin from herbal wood; 2) Ca-Ls contained rich guaiacyl( G-type) and syringyl( S-type) structure unit; 3) the pyrolysis of Ca-Ls was divided into four stages,and the main pyrolysis temperature range was 150- 450 ℃; 4) when heating rate was 10,20 and 30 ℃ / min,the biggest weight loss peak on the DTG curves migrated to higher temperature,meanwhile,as the heating rate increased,the response time for sample particles to reach the desired pyrolysis temperature became shorter. Thus the thermal decomposition rate increased and the process of thermal decomposition of Ca-Ls was changed.