| The lack of forest resources is an important resulting reason fornon-wood fibrous materials and secondary fiber ones occupying a largeproportion of raw materials in Chinese paper industry for a long time, soeffective use of wood fiber and vigorous development of non-wood resourcesand reuse of secondary fiber are important subjects in the development of pulpand papermaking industry in China. Various chemicals were added tochemical-mechanical pulp or wheat straw chemical pulp or recycled pulp in theprocess of making high quality paper in order to improve the paper quality. Theapplication of starch and starch derivative as chemical additives is extremelyimportant. Gelatinized starch added to pulp was mixed in the process of currentpulping. Starch was adsorbed on the surface of pulp fiber to the greatest extentby electrostatic attraction, but unabsorbed starch was dispersed in the pulp waterphase syetem. The amount of adsorption of starch on the surface of pulp fiberdirectly affected the quality of paper, so taking researches on the retention of thehigh addition of starch in the paper will be meaningful for a factory to makegood use of starch.The surface of alkaline peroxide mechanical pulping （APMP） fiber orwheat straw chemical pulp fiber or old corrugated containers（OCC）pulp fiberwas coated successively with modified starch such as cationic starch and anionicstarch by the methods of orthogonal test and single factor experiment, which wasbased on layer-by-layer self-assembly technique and electrostatic attractionmechanism of cation with anion. The effects of inorganic electrolyte species,inorganic electrolyte concentration, pulp concentration, dosage of starch eachtime, pH and each adsorption time on the adsorption of starch on the surface ofpulp fiber were mainly investigated. Under the optium technological conditionsof inorganic electrolyte cooperative starch coating pulp fiber, the pulp fiber wascoated with multilayer starch. The effect of starch coating layer number on theadsorption of starch on the surface of pulp fiber and Zeta potential was discussed. The paper performances of pulp fiber adsorbing three-layer starch cooperatedwith AlCl3were separately compared with blank sample and pulp fiber adsorbingmonolayer starch and pulp fiber adsorbing three-layer starch.When AlCl3concentration was36mmol·L-1, the pulp concentration was4.0%, the each adsorption time was15min, the dosage of starch each time was11mg·g-1fiber and pH was5.0, the adsorption of starch on the surface of APMPpulp fiber adsorbing three-layer starch cooperated with AlCl3was31.48mg·g-1fiber. Tensile index of its paper was increased by51.93%, tearing index by76.35%, burst index by110.61%, ring crush index by50.99%compared with theblank sample. Tensile index of its paper was increased by22.52%, tearing indexby28.32%, burst index by51.09%, ring crush index by18.83%compared withthe APMP pulp fiber adsorbing monolayer starch. Tensile index of its paper wasincreased by9.30%, tearing index by11.53%, burst index by15.83%, ring crushindex by9.45%compared with the APMP pulp fiber adsorbing three-layer starch.Under the same optium technological conditions, the adsorption of starch on thesurface of APMP pulp fiber adsorbing eight-layer starch cooperated with AlCl3was63.36mg·g-1fiber and its Zeta potential was-5.36mV.When AlCl3concentration was12mmol·L-1, the pulp concentrationwas4.0%, the each adsorption time was10min, the dosage of starch each timewas9mg·g-1fiber and pH was5.0, the adsorption of starch on the surface ofwheat straw chemical pulp fiber adsorbing three-layer starch cooperated withAlCl3was24.03mg·g-1fiber. Tensile index of its paper was increased by45.19%,tearing index by66.17%, burst index by21.38%, ring crush index by35.60%compared with the blank sample. Tensile index of its paper was increased by23.05%, tearing index by28.74%, burst index by9.32%, ring crush index by16.03%compared with the wheat straw chemical pulp fiber adsorbing monolayerstarch. Tensile index of its paper was increased by10.84%, tearing index by13.82%, burst index by5.39%, ring crush index by8.22%compared with thewheat straw chemical pulp fiber adsorbing three-layer starch. Under the sameoptium technological conditions, the adsorption of starch on the surface of wheatstraw chemical pulp fiber adsorbing eight-layer starch cooperated with AlCl3was46.08mg·g-1fiber and its Zeta potential was-2.69mV.When AlCl3concentration was108mmol·L-1, the pulp concentration was5.0%, the each adsorption time was10min, the dosage of starch each timewas7mg·g-1fiber and pH was5.0, the adsorption of starch on the surface ofOCC pulp fiber adsorbing three-layer starch cooperated with AlCl3was17.43mg·g-1fiber. Tensile index of its paper was increased by39.04%, tearingindex by30.95%, burst index by31.65%, ring crush index by117.05%compared with the blank sample. Tensile index of its paper was increased by19.86%, tearing index by10.07%, burst index by11.83%, ring crush index by59.66%compared with the OCC pulp fiber adsorbing monolayer starch. Tensileindex of its paper was increased by11.27%, tearing index by5.64%, burst indexby8.33%, ring crush index by18.05%compared with the OCC pulp fiberadsorbing three-layer starch. Under the same optium technological conditions,the adsorption of starch on the surface of OCC pulp fiber adsorbing eight-layerstarch cooperated with AlCl3was35.28mg·g-1fiber and its Zeta potential was-6.54mV. |
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