Dissertation
Dissertation > Industrial Technology > Light industry,handicrafts > Paper Industry > Basic theory > Pulp and chemical

Effects of Enzyme/Chemical Agents on Refining of Plant Fiber

Author HuangJinFeng
Tutor WuZongHua
School Fujian Normal University
Course Polymer Chemistry and Physics
Keywords plant fiber refining enzyme chemicals energy consumption properties
CLC TS713
Type Master's thesis
Year 2011
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The effects of the enzymes, chemicals and their mixtures on refining of secondary fiber from old carton were investigated to improve the physical properties of the fiber and reduce the energy consumption. The relations between enzyme species and dosage, pretreatment time and pH value and beating degree as well as paper mechanical strength of the fiber were analyzed. Effects of NaOH, polyacrylamide, sodium polyacrylate or commodity amylase on refining of secondary fiber were investigated. The complex of enzyme and chemicals with obviously effects and the pretreatment process conditions were studied.The results also showed that one of the important roles of amylase pretreatment and refining was to remove small fibers and impurities in the second fiber.Based on the results in the last chapter, effects of the enzymes and the chemicals on refining of a bleached softwood pulp and a bleached hardwood pulp were further investigated. The results showed that there was a marked improvement on the mechanical strength of bleached pulp owing to pretreatment of the enzyme/chemical compounds, effect of pretreatment to bleached hardwood pulp was better than that of bleached softwood pulp. The effect, it was satisfactory that bleached pulp was treated by neutral cellulase or high temperature resistant amylase alone. However, when both of enzymes were combined, the mechanical strength of bleached pulp was stepped down. Effect of NaOH was the best in every chemical.In order to solve the problems of high refining energy consumption, low strength properties and easily yellowing of TMP from masson pine, the effects of refining strength and pretratment by adding enzymes and chemicals on refining of TMP were investigated. The study found that the TMP mechanical strength had a marked improvement by adding acrylamide. The samples were analyzed by means of IR spectrum, X-ray photoelectron spectroscopy and Dynamic Mechanical Thermal Analysis, the results showed that mechanical force may lead to generate free radicals of lignin, as well as cause graft polymerization of acrylamide and lignin to improve the mechanical properties of pulp. Effects of using neutral cellulase, high temperature resistant amylase or acrylamide separately were better than both of them combined.

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