AlCl3协同淀粉多层包覆APMP浆纤维研究

基于聚电解质层层沉积技术,本文通过AlCl3协同阴/阳离子淀粉多层交替包覆APMP纸浆纤维,从而探讨AlCl3协同淀粉包覆APMP纸浆纤维的层数对淀粉吸附量、纸浆Zeta电位和成纸性能的影响。结果表明,当AlCl3的浓度为36 mmol.L-1,纸浆浓度为4.0%,每次吸附时间为15 min,每次淀粉用量为11 mg.g-1纤维,pH为5.0的条件下,淀粉八次交替包覆APMP浆纤维表面的淀粉吸附量为63.36 mg.g-1纤维,纸浆Zeta电位为-5.36 mV,随着淀粉包覆纸浆纤维层数增加,纸浆纤维成纸的抗张指数、耐破指数及环压指数均呈上升趋势,而撕裂指数先增加后降低。AlCl3协同阴/阳离子淀粉多层交替包覆APMP纸浆纤维产物的扫描电镜(SEM)表明,AlCl3协同阴/阳离子淀粉三层包覆纸浆纤维表面的淀粉复合膜粗糙程度高于三层淀粉直接包覆纸浆纤维表面复合膜粗糙程度。     

无机盐协同淀粉多层包覆OCC浆纤维对淀粉吸附量的影响

基于聚电解质层层沉积技术,通过在OCC浆纤维表面进行阳离子淀粉与阴离子淀粉交替包覆的方法,研究了无机盐种类、每次包覆的淀粉用量、纸浆浓度、每次包覆吸附时间、pH值和无机盐浓度对OCC浆纤维表面淀粉吸附量的影响。结果表明,无机盐协同淀粉3层包覆OCC浆纤维的适宜工艺条件为:AlCl3浓度108 mmol/L,纸浆浓度5.0%,每次包覆吸附时间10 min,每次淀粉用量9 mg/g纤维,pH值5.0。在适宜的工艺条件下,无机盐协同淀粉3层包覆OCC浆纤维表面淀粉吸附量为22.78 mg/g纤维,其纤维表面的淀粉保留率为84.4%,与吸附单层阳离子淀粉的试样相比较,AlCl3协同淀粉包覆OCC浆纤维表面淀粉吸附量增加了180.89%。     

多层淀粉包覆杨木APMP纸浆纤维对成纸性能的影响研究

基于层层沉积技术及阴阳离子静电吸附作用的理论基础,通过在杨木APMP纸浆纤维表面依次包覆阳离子淀粉（CS）、阴离子淀粉（AS）和阳离子淀粉（CS）的方法,主要讨论了无机电解质种类、纸浆浓度、淀粉用量对成纸性能和淀粉保留率的影响。研究结果表明：当AlCl3浓度为12．0mmol／L,纸浆浓度为1．6％,每层淀粉用量为50mg／g（纤维）,每层吸附时间5min,pH：5．0时,同未吸附淀粉的空白样相比,多层淀粉包覆APMP浆成纸的耐破指数、环压指数、撕裂指数及抗张指数分别增加了95．74％、62．88％、95．55％和88．55％;同吸附单层阳离子淀粉的空白样相比较,多层淀粉包覆APMP浆的淀粉保留率增加了97．55％,成纸的耐破指数、环压指数、撕裂指数及抗张指数分别增加了41．54％、42．89％、53．02％和45．79％     

多层包覆技术用于提高APMP浆成纸的淀粉含量及强度

将阳离子淀粉和阴离子淀粉作为聚电解质,在APMP纸浆纤维表面形成多层沉积膜。研究结果表明,用处理后的APMP纸浆抄片,其内结合力、抗张强度以及撕裂度都有大幅度的提升。     

阳离子淀粉絮凝剂制备及脱色性能研究

以马铃薯淀粉为原料,3～氯-2-羟丙基三甲基氯化铵为醚化剂,干法工艺制备了季铵型阳离子淀粉絮凝剂(DS=0.099),以荧光黄E-8G染料溶液模拟印染废水,研究了染料浓度、絮凝剂用量、脱色时间和废水pH对脱色率和吸附量的影响.结果表明:阳离子淀粉絮凝剂对碱性印染废水有较好的脱色能力;在废水pH为12.5,染料浓度113.5 mg/L,絮凝剂用量120 mg/L,脱色时间2 h条件下,脱色率达63.2%,吸附量为0.612 mg/mg;絮凝剂对酸性染料分子的吸附符合Langmuir单分子层吸附理论.     

pH值、无机电解质对PAE和CMC在纤维上吸附量的影响

通过测量纸浆Zeta电位以及聚合电解质的吸附量等方法,研究了pH值和无机电解质对阳离子聚酰胺-环氧氯丙烷树脂(PAE)和阴离子羧甲基纤维素(CMC)在纤维表面吸附量的影响。实验结果证明吸附量随纸浆悬浮液中无机电解质浓度的升高先增大后减小;随pH值的升高而增大。     

淀粉/聚胺复合物纸张增强机理初探

研究了淀粉/聚胺复合物、阳离子淀粉及原淀粉在纸浆上的吸附类型,测定了淀粉/聚胺混合糊液及单一组分的黏度,探讨了淀粉/聚胺复合物在不同浆种纸张中的作用效果。结果表明,淀粉与聚胺形成了复合物,该复合物对再生浆的作用效果与阳离子淀粉相当,具有明显的增强作用。淀粉/聚胺复合物用量为1.5%时,可使纸板的裂断长增加22.6%,纤维留着增加率提高了6.8%。淀粉/聚胺复合物在纸浆纤维上的吸附为化学吸附和物理吸附共同作用的结果,与阳离子淀粉的吸附相似。     

酶促合成松香淀粉酯对苯酚的吸附研究

为探究酶促合成松香淀粉酯(RAS)对苯酚的吸附机理,考察了苯酚的初始浓度、吸附时间和吸附温度对吸附过程的影响,并利用吸附模型对实验数据进行拟合分析。结果表明:吸附量随着苯酚初始浓度的提高或吸附温度的下降而呈上升趋势(p <0.01);吸附平衡时间为1h。在温度为25℃、时间为1h、苯酚初始浓度为100mg·L-1的条件下,其吸附量可达1.334mg·g-1。吸附模型的拟合结果表明,RAS对苯酚的吸附量与苯酚浓度线性相关、RAS对苯酚的吸附过程是可自发的、放热的表面物理吸附过程。     

纸浆特性对阳离子淀粉吸附作用的影响

在多数情况下,聚合电解质如：阳离子淀粉分子不能渗透到纤维细胞腔内。它们的吸附取决于纤维和细小纤维的表面特性。研究表明吸附到硬木上的阳离子淀粉比软木上的更多。比较两种浆的特性以确定纤维表面上的电荷是阳离子淀粉吸附的主要特性。     

纸浆特性对阳离子淀粉的吸附作用的影响

在多数情况下,聚合电解质如:阳离子淀粉分子不能渗透到纤维细胞腔内。它们的吸附取决于纤维和细小纤维的表面特性。研究表明吸附到硬木上的阳离子淀粉比软木上的更多。比较两种浆的特性以确定纤维表面上的电荷是阳离子淀粉吸附的主要特性。     

漂白麦草浆细杂组份对阳离子淀粉吸附的影响

本文研究了漂白麦草浆中细杂组份(通过100目,其中大部分是杂细胞,如薄壁细胞,表皮细胞)对阳离子淀粉吸附的影响。 实验表明,漂白麦草浆中细杂组份的比表面积明显大于纤维组份(保留在100目以上)的比表面积。阳离子淀粉优先吸附在比表面积大的细杂组份上。纤维组份的吸附能力受化学环境的影响较细杂组份更为敏感。     

阳离子淀粉-膨润土复合絮凝剂对活性染料的吸附

针对膨润土和阳离子淀粉单独用于处理印染废水时存在脱色率低和固液难分离的问题,采用一步法将阳离子淀粉和膨润土同时投入到活性红X-3B的染色废水中,使阳离子淀粉与膨润土相互吸附,形成结构疏松、比表面积较大的阳离子淀粉-膨润土复合絮凝剂,同时吸附废水中的染料,对其进行脱色。以阳离子淀粉-膨润土复合絮凝剂对活性红X-3B染料废水的脱色率为考核指标,经过实验研究,确定了最佳的应用工艺：阳离子淀粉与膨润土在染料废水中的投加量总量为1.25 g/L,阳离子淀粉与膨润土的质量配比为1:1,印染废水的pH 值为7,不添加氯化钠,处理后印染废水的脱色率可达90%以上。在此基础上通过建立等温吸附曲线,确定了阳离子淀粉-膨润土复合絮凝剂的等温吸附线为典型的L-型,属于表面配位吸附。     

Interaction of cationic starch derivatives and cellulose fibres in the wet end and its correlation to paper strength with a statistical evaluation

The adsorption onto a softwood pulp of cationic modified starches with a degree of substitution (DS) ranging from 0.015 to 0.130 and native potato starch was investigated using a method based on size exclusion chromatography‐multi angle laser light scattering (SEC‐MALLS). This technique provides information about the amount and molecular composition of the adsorbed starch product such as the AP–AM‐ratio, the average MW and molar mass distribution. Factors influencing adsorption, like the electrolyte content in the suspension and the initial starch polysaccharide concentration, were investigated. Furthermore, hand sheets were made and the resulting mechanical paper strength was tested. Results were analysed statistically using analysis of variance. Representative results were discussed in detail. In general, low‐substituted cationic starch (DS 0.030) exhibited a higher degree of adsorption and resulted in high paper strength when there was a low electrolyte content in the starch–pulp‐suspension. However, high amounts of electrolytes impeded electrostatic interaction of the charged groups of the starch polysaccharides and cellulose fibre due to partial screening and therefore strongly limited adsorption. This resulted in lowered mechanical paper strength. The water quality of the suspensions had little impact on the polyelectrolyte adsorption of the highly substituted cationic starch (DS 0.100). However, paper strength was markedly higher in the case of starch adsorption where there was a high ionic content and when both starch polysaccharides–AP and AM– were adsorbed. The initial starch concentration determined starch adsorption both quantitatively and qualitatively and subsequently paper strength as well. The relation between adsorption behaviour and paper strength was discussed, particularly in the case of 6% initial starch concentration. In deionised water (DW), the low‐substituted starch (DS 0.03) adsorbed onto the pulp to a greater extent with an AP–AM‐ratio similar to that of the initial starch. Moreover, this achieved the best strength properties in contrast to 36 dGH, where less starch adsorbed and that being almost exclusively AP. In water with 36 dGH, the highly substituted starch (DS 0.100) with both the AP and AM was absorbed and this resulted in higher paper strength. In contrast, AM was almost exclusively adsorbed in DW. Increasing the initial starch concentration increased the amount adsorbed while subsequently changing the AP–AM‐ratio towards increased AM adsorption and decreased AP adsorption in the case of DS 0.100 in DW. Exclusive adsorption of AM markedly lowered the development of the paper strength.     

Method for Quantitative and Molecular Characterisation of Adsorbed Starch Polysaccharides on a Papermaking Pulp by SEC‐MALLS Measurements and Correlation with Paper Strength

A laboratory‐scale method for determining the molecularly dispersed amount of cationic starch adsorbed on a papermaking pulp was developed. The starch was molecularly dispersed by pressure cooking and was characterised by SEC‐MALLS (Size Exclusion with Multi‐Angle Laser Light Scattering) before and after the adsorption experiment. The adsorbed amount was calculated from the depletion of starch polymers in the starch‐fibre suspension. The molecular composition of the adsorbed starch product was determined from the difference in the SEC chromatograms before and after adsorption. In addition, handsheets were formed to correlate starch adsorption on the pulp with the resulting paper strength. The value of the method was demonstrated using the example of a low DS cationic potato starch derivative. This sample from a slurry process was adsorbed to a significantly higher extent in virtually electrolyte‐free deionised water (DW) than in water with a high electrolyte content (36 degrees German Hardness – 36 dGH). In DW, both amylopectin and amylose were adsorbed on the pulp, whereas in water of 36 dGH only the amylopectin‐rich fraction was adsorbed. A correlation between starch adsorption as a function of water quality and the resulting paper strength was found. The amount and molecular composition of the adsorbed starch product influenced paper properties.     

水包水阳离子聚丙烯酰胺乳液对苇浆的助留作用研究

研究了水包水阳离子聚丙烯酰胺(CPAM)乳液对漂白烧碱法苇浆的助留作用。通过单条件确定法,考查了CPAM用量(相对于绝干纤维)、搅拌速度、CPAM加入后的作用时间、硫酸铝用量、浆料pH值以及水中盐浓度等因素对其助留效果的影响,确定了CPAM乳液的最佳应用条件CPAM用量为0.04%(相对于绝干纤维),加入CPAM后的反应时间为2min,搅拌速度为200r/min,硫酸铝用量为3%,pH值为4.0,NaCl加入量为0。实验还证明CPAM乳液对水溶液中杂离子的累积具有一定的抵抗能力,能够满足造纸厂封闭循环用水的要求,同时在酸性至中碱性的浆料pH值范围内,其助留效果都很好。