Impact of residual extractives on the thermal stability of softwood Kraft pulp

编号 020036002

推送时间 20220912

研究领域 林产化工 

年份 2022 

类型 期刊 

语种 英语

标题 Impact of residual extractives on the thermal stability of softwood Kraft pulp

来源期刊 Cellulose

期 第360期

发表时间 20220823

关键词 Extractives;  Softwood;  Kraft pulp;  Thermal stability;  Thermogravimetric analysis (TGA);  Supramolecular order;  Carbohydrate composition; 

摘要 Wood extractives are known to cause problems during the production of pulp and paper and to impact their mechanical properties. In the present work, we systematically explored whether minute residual amounts of extractives that reprecipitate on the fiber surface in the final stages of the pulping process would lower the thermal resilience of softwood Kraft pulp. Pulp samples subjected to different extraction methods were characterized by means of thermogravimetric analysis. The compound classes constituting the respective extracts were identified and quantified via gas chromatography-mass spectrometry/flame ionization detector (GC-MS/FID) and the influence of the individual compound classes on the thermal stability of the samples was investigated separately. Soxhlet extraction with an ethanol/toluene solvent system clearly led to increased thermal stability. Besides fatty acids and resin acids also sterols and sterol esters that do not carry carboxylic acid functionalities contributed to the deterioration of the thermal pulp properties. Lateral order indices derived from Fourier transformed infrared spectra and crystallinity indices derived from solid-state C-13 nuclear magnetic resonance spectra indicate that upon thermal degradation, the presence of even minute amounts of extractives leads to an increased degree of supramolecular disorder. Moreover, the characterization of the samples' carbohydrate composition by means of acidic hydrolysis showed a tendency towards facilitated pyrolysis of the hemicelluloses if extractives were present in the pulp.

服务人员 尚玮姣

服务院士 宋湛谦

PDF文件 浏览全文