Effect Of Enzyme Treatment On Poplar Hyp Fiber Morphology And Physical Structure

Papermaking industry in China are faced with the situation of the shortage of paper-making raw material, especially the wood raw material, and the serious pollution industry. Production of high yield pulp (HYP) will be the effective way to improve the utilizing efficiency of pulping raw material. The refining stage consumes a great deal of energy in HYP producing process, and the main reason are that the P and S1 layer of cell wall are difficulty to break in conventional refining. Biology pretreatment can reduce the energy consumption and improve the pulp properties.The cellulase and xylanase PE-89 were used to modify the APMP and BCTMP of fast-growing poplar in this thesis. The optimal condition for the enzyme treatment were selected by analysis and comparison of beating degree, physical strength, the optical properties, and fiber properties of the untreated and treated pulp. The fiber quality of treated pulp were analyzed by Fiber Quality Analyzer (FQA), and the morphology and surface character of the fibers structure of treated pulp were observed by Environmental Scanning Electronic Microscope (ESEM) and Atomic Force Microscope (AFM) , and pulp's crystallinity were detected by X-ray Detector (XRD). By detecting the Zeta potential, the carboxyl content and the dissolved charge of the untreated and treated pulp were detected to analyze influence of enzyme treatment on the end wet chemistry of pulp.Different fiber materials are used reasonably according the fiber morphology, physical structure and different characteristic of different pulp, and the paper's strength are forecasted, and experiment and production are guided.Modification of fast-growing poplar APMP treated by cellulose and the effection of cellulose treatment on wet-end charge of the pulp were researched. The beating degree of the treated APMP increased, and tear index ,breaking length, burst index and water retention value of the treated APMP increased respectively 5%, 4.2%, 12%, and 5.14% when the optimal treatment condition were cellulose dosage 3IU·g-1, pH 5.0, time 90 min, and temperature 55℃.Compared with the untreated APMP, the Lww of treated fibers increased 0.011 mm,the carboxyl content reduces 7.56 m mol·kg-1, the Zeta potential (negative value) decreases 1.2 mv, and the dissolved charge reduces by 6.45μeq·g-1. The observation results of treated APMP observed by SEM and AFM showed that the treated fibers by cellulase were soft, many hollows on the fiber surface appeared, and fibrillation extent of treated pulp were better, and the treated pulp were easy for refining or beating. The crystallinity of the treated fiber observated by the XRD increased by 2.87%.Modification of fast-growing poplar APMP treated by xylanase and the effection of xylanase treatment on wet-end charge of the pulp were researched. The beating degree of the treated APMP increased 2.0°SR at 25,000 beating revolution by PFI mill, and tear index, breaking length, burst index and water retention value of the treated APMP increased respectively 5%, 4.9%, 14%, and 5.87% when the optimal treatment condition were xylanase dosage 20IU·g-1, pH 7.0, time 90 min, and temperature 50℃. Compared with the untreated APMP, the Lww of treated fibers increased 0.024 mm, the carboxyl content reduced by 9.43 m mol·kg-1, the Zeta potential (negative value) decreased by 1.7 mv, and the dissolved charge reduced by 4.03μeq·g-1. The observation results of treated APMP observed by SEM and AFM showed that the treated fibers by xylanase were soft, many hollows on the fiber surface appeared, and fibrillation extent of treated pulp were better, and the treated pulp were easy for refining or beating. The crystallinity of the treated fiber observated by the XRD increased by 2.28%.Modification of fast-growing poplar BCTMP treated by xylanase and the effection of xylanase treatment on wet-end charge of the pulp were researched. The beating degree of the treated BCTMP increased 2.0°SR at 25,000 beating revolution by PFI mill, and tear index, breaking length, burst index and water retention value of the treated BCTMP increased respectively 4.2%, 3.0%, 18%, and 3.82% when the optimal treatment condition were xylanase dosage 20IU·g-1, pH 7.0, time 90 min, and temperature 50℃. Compared with the untreated BCTMP, the Lww of treated fibers increased 0.010 mm, the carboxyl content reduced by 2.23 m mol·kg-1, the Zeta potential (negative value) decreased by 2.5 mv, and the dissolved charge reduced by 3.93μeq·g-1. The observation results of treated BCTMP observed by SEM and AFM showed that the treated fibers by xylanase were soft, many hollows on the fiber surface appeared, and fibrillation extent of treated pulp were better, and the treated pulp were easy for refining or beating. The crystallinity of the treated fiber observated by the XRD increased by 2.08%.