Abstract
Southern pine wood chips were pretreated with green liquor and the pretreated wood chips were pulped using kraft chemistry. The resultant physical and chemical characteristics of the pulps were contrasted to pulps from conventional kraft pulping. The lignin contents and structures in the native wood chips, the green liquor pretreated wood chips, conventional kraft pulps and kraft pulps made after green liquor pretreatment were investigated and compared. The P-31-NMR spectra of wood and pulp samples were obtained after dissolving them in an ionic liquid after enzymatic hydrolysis. The dissolved lignin samples from the wasted liquor after the green liquor pretreatment, the black liquors after conventional kraft pulping and kraft pulping after green liquor pretreatment were isolated. Their molecular weights and structures were analyzed by GPC and P-31-NMR. spectra respectively. The delignification chemistry in green liquor pretreatment, conventional kraft pulping and kraft pulping after green liquor pretreatment are discussed and compared, indicating that green liquor pretreatment significantly affects the chemical and physical response of wood chips to kraft pulping.