Effects of process and source on elastic modulus of single cellulose fibrils evaluated by atomic force microscopy

A test method to measure cellulose fibril elastic modulus using atomic force microscopy was used to investigate the effects of process and source on the moduli of single cellulose fibrils. The cellulose fibrils were generated from cellulose by mechanical treatments. Individual fibrils were suspended over a micro scale groove etched on a silicon wafer. A nano-scale three-point bending test was performed to obtain the elastic moduli. The results indicated that the elastic moduli of cellulose fibrils were not significantly different between 30 min and 60 min of high intensity ultrasonic treatment for Lyocell fiber, between isolation methods of ultrasonic and homogenizer treatment for pure cellulose fiber, and between different cellulose sources of pulp fibers treated by homogenizer regardless the effects of sample size coupled with inherent variation in the raw material. The elastic modulus of Lyocell fibrils with diameters from 150 to 180 nm was evaluated to be 98 ± 6 GPa. Modulus values decreased dramatically when the diameter was more than 180 nm.     

Steady state modelling and simulation of an indirect rotary dryer

A steady state model for a fish meal indirect pilot plant rotary dryer with steam tubes is developed. The model is based on mass and energy balances and heat transfer constitutive equations. Simulated and experimental results are presented. The moisture condition of fish meal predicted by the model agrees satisfactorily with experimental values obtained in the pilot plant dryer within the range of operating conditions explored.     

Ion conductivities and interfacial characteristics of the plasticized polymer electrolytes based on poly(methyl methacrylate-co-Li maleate)

The plasticized polymer electrolytes composed of poly(methyl methacrylate-co-Li maleate), lithium perchlorate, and ethylene carbonate as a plasticizer, were newly prepared. The ion conductivities of the plasticized polymer electrolytes based on the poly(methyl methacrylate-co-Li maleate) were found to be dependent on the ion content of the ionomer, poly(methyl methacrylate-co-Li maleate), in the polymer electrolyte, and the polymer electrolyte based on the ionomer with 8.5 mol% ion content showed the maximum ion conductivity.The interfacial resistance at the polymer electrolyte/lithium interface and the cationic transference number were also investigated as a function of the ion content of the ionomer in the polymer electrolyte. The interfacial resistances as well as the cationic transference numbers of the polymer electrolytes were found to be also dependent on the ion content of the ionomer in the polymer electrolyte. Ion aggregations in the ionomer seemed to significantly influence the electrochemical behavior of the polymer electrolytes based on the ionomer.     

描述桉木硫酸盐浆氧脱木素过程动力学的新模型

以桉木硫酸盐浆为原料,考察了氧脱木素温度、氧压、NaOH用量及反应时间对木素脱除程度的影响及残碱的变化规律。研究发现,氧脱木素过程溶液的NaOH浓度与纸浆卡伯值(用于表征纸浆木素含量)的自然对数之间呈线性关系;结合这一关系,建立了引入碱浓动态变化的氧脱木素动力学模型。结果表明,该模型能很好地预测桉木硫酸盐浆在各种工艺条件下的纸浆卡伯值(R2=0.980)。与传统氧脱木素动力学模型相比,该模型在参数量的控制及参数设置的合理性方面更具优势;由于考虑了过程残碱的变化,动力学模型参数的拟合结果更接近理论值。     

硅系合成革离型纸的研究

优选出耐热性较好的3种丙烯酸类乳液作为底涂主剂,水性有机硅树脂作为离型剂,并通过混合正交实验探讨了离型层配比、底涂主剂、底涂压光压力及离型层涂布量对离型纸首次剥离强度和可重复使用次数的影响大小,由此确定了达到最佳离型性能,即首次剥离强度为8.7×10-2 kN/m,可重复使用次数为35次的相应涂层工艺条件是:底涂主剂采用的丙烯酸类乳液,其Tg为6℃、涂4-杯黏度20 s时原液固含量为45.0%、原液黏度为300 mPa.s。底涂压光压力为8 MPa,离型层涂布量为1～2 g/m2,离型层配比为4∶1,在该工艺条件下自制硅系合成革离型纸,其耐溶剂性与进口纸相当或更优。     

纳米TiO2胶体与改性淀粉双元体系的助留助滤效果

利用动态滤水(DDJ)实验,通过细小纤维单程留着率和滤水时间对纳米TiO2胶体与改性淀粉双元体系的助留助滤效果进行考察。研究该双元体系复配对纸张强度的影响及对白水循环中溶解和胶体物质(DCS)的除去与控制。结果表明,与阳离子淀粉(CS)相比,两性淀粉(AmS)与纳米TiO2双元体系有更好的协同作用,当淀粉用量不同、纳米TiO2用量约为0.4%时,细小组分单程留着率可增加5～12个百分点;纳米TiO2对AmS有正面的影响;AmS与纳米TiO2胶体复配对DCS的去除效果明显。     

球磨法制备超微细蒽醌及其表征

介绍了超微细蒽醌制备方法和表征手段。该法首先是利用球磨机将商品蒽醌球磨成细小蒽醌;然后,在十二烷基苯磺酸钠的作用下使制得的蒽醌颗粒悬浮液通过物理沉降,将较大颗粒的蒽醌分离,从而获得了超微细蒽醌的悬浮液;最后分别用可见分光光度计及马尔文粒度分析仪对超微细蒽醌悬浮液中蒽醌含量及粒度分布进行测定与表征。结果表明,用本实验的球磨机制备超微细蒽醌的适宜条件为:球磨时间12 h、十二烷基苯磺酸钠用量10%。对超微细蒽醌悬浮液中蒽醌含量及粒度分布进行测定时应充分搅拌后将悬浮液静置30 min时取样为宜。本方法可制备含量高、粒径小、粒度分布均一的超微细蒽醌悬浮液。     

基于分子分离技术的装置在造纸废水处理中的研究

对一种基于分子分离技术的装置的结构、运行方法、原理进行了详细描述,并将此装置用于深度处理硫酸盐制浆漂白中段废水。结果显示,该装置处理造纸废水效果显著,只需要处理20 min,废水的CODCr去除率超过95%,色度、BOD5和AOX的去除率均超过98%,有机物种类大大减少,高毒性大分子物质可以被完全去除,基本都被降解为低分子质量的有机酸。该装置利用电能处理造纸废水中的污染物,不仅环保而且节能,处理时消耗的能量少,降低了废水处理成本,可避免产生二次污染。     

一种新型阳离子复合表面施胶剂的研制及应用

研制了一种新型阳离子复合(AKD-石蜡)表面施胶剂,考察了该施胶剂对瓦楞原纸的施胶效果。结果表明,自制新型阳离子复合表面施胶剂制备工艺简单;相同施胶量下与阳离子SAE施胶剂相比,新型阳离子复合表面施胶剂施胶纸的纵向环压指数、耐破指数和耐折度分别提高14%、8%和25%;当施胶量为2 kg/t纸时,与阳离子SAE施胶剂相比,表面施胶成本降低4元/t纸。     

造纸法烟草薄片废水混凝预处理研究

以聚合氯化铝(PAC)和聚合硫酸铁(PFS)为混凝剂,4种不同类型的聚丙烯酰胺(PAM)为助凝剂,对造纸法烟草薄片废水进行混凝处理,分别考察了 pH值、混凝剂用量、助凝剂用量对混凝效果的影响.结果表明,PAC与PFS对COD、氨氮和悬浮物(SS)去除率效果相当,但PAC的脱色效果更佳.相对分子质量700万、离子化度为15％的阳离子聚丙烯酰胺(PAM4)与PAC的复配体系具有最佳的混凝效果,在pH值为6 5、PAC用量为500mg/L、PAM4用量为5mg/L的优化工艺条件下,COD、氨氮、色度和SS去除率分别为70.8％、84.8％、72.3％和98.5％.废水的铝含量分析表明,该体系非但没有产生残留铝,而目大幅去除了原水中的铝.处理后废水的紫外吸收光谱表明,有机物含量降低.