EFFECT OF ALKALINE PEROXIDE TREATMENT ON THE LIGNIN STRUCTURE OF ASPEN P-RC APMP
Residual lignins were isolated from untreated and alkaline peroxide treated aspen P-RC APMP. The structural changes and degradation of residual lignin occurring during second alkaline peroxide impregnation were identified by 2D-NMR techniques, 31P-NMR, as well as GPC. 2D-NMR results showed that guaiacyl unit was easier to be oxidized by peroxide than syringyl unit. Double bond groups and β-O-4’ type sub-structure with α-carbonyl in lignin side chain were easy degraded, while β-β’ and β-5’ type sub-structure were stable to alkaline peroxide. According to the results of 31P-NMR, the contents of both aliphatic OH and COOH groups in residual lignin increased whilst total phenolic OHs decreased obviously after alkaline peroxide treatment.Carboxylic acids were formed by oxidative attack of peroxide toward the structures of α-carbonyl and double bond groups in lignin side chain, as well as phenolic lignin moieties. GPC analysis farther confirmed that lignin has been somewhat oxidized and degraded during alkaline peroxide treatment.
alkaline peroxide treatment aspen P-RC APMP residual lignin 31P-NMR 2D-NMR GPC
Yingjuan Fu Yanzhu Guo Menghua Qin Qinghua Xu Na Liu
Shandong Polytechnic University,Jinan,Shandong,250353,China
国际会议
International Mechanical Pulping Conference 2011(2011国际机械浆学术会议)
西安
英文
75-78
2011-06-26（万方平台首次上网日期，不代表论文的发表时间）