稻草芦苇及其浆料制备羧甲基纤维素的比较

研究了直接由草粉或浆料制备羧甲基纤维素钠的溶剂适应性,并对产品的结构、粘度、取代度做了分析。结果表明,丙酮做溶剂时羧甲基纤维素合成的得率最高、取代度最大。草粉和草浆在丙酮溶剂中经过一次反应得到的羧甲基纤维素取代度均可达0.7以上。红外光谱表明,从草粉和从浆料制得的羧甲基纤维素样品结构上没有明显差别。以不同程度预处理的草粉为原料,可以得到取代度0.5~1.1之间的不同品质的羧甲基纤维素产品。     

尾叶桉磺化化机浆磺化预处理及其纤维特性的研究

本文采用不同的磺化预处理条件，探讨对尾叶桉（Eucalyptuseurophylla）横化化机浆性质的影响，从而制定出较佳磺化预处理工艺条件。另外测试磺化、磨浆后影响纸浆主要性质的纤维长度分布、比表面积、压缩性和用扫描电子显微镜观察不同打浆度下纤维形态的变化。研究表明，纤维比表面积、纤维长度和浆料压缩性指标可以很好地评价尾叶桉磺化预处理和磨浆过程中纤维的特性，以及成纸物理性能。PFI磨浆处理表明，尾叶扶纤维比较短，磺化后的纤维不宜过重磨浆处理，以免造成纤维过短而影响纸浆物理强度性质。     

Electrochemical investigation of copper–DTPI interactions

The electrochemical behavior of copper in the absence and presence of a dithiophosphinate type collector, sodium diisobuthyldithiophosphinate (NaDTPI), was determined to investigate the interactions between a copper surface and NaDTPI as a function of pulp potential (Eh) and pH. The electrochemical studies were performed by Cyclic Voltammetry (CV) in the −355 to +1550 mV (SHE) potential range and at different pHs from slightly acidic to strongly alkaline conditions. The electrochemical studies were carried out for copper and DTPI alone as well as with DTPI added copper system. DTPI addition had considerable effects on the electrochemical behavior of copper. CuDTPI formation was the main reaction at all pHs through a mixed mechanism and oxidation of the copper surface was followed by a chemical reaction between copper and DTPI ions. Formation of a cupric metal-collector complex, Cu(DTPI)₂, was observed only in acidic conditions in the form of an unstable surface compound.     

表面活性剂Tween 80对麦草浆次氯酸盐漂白的影响

研究了聚氧乙烯山梨醇酐单油酸酯(Tween80)对麦草烧碱浆次氯酸盐漂白的助漂作用。对次氯酸盐与Tween80同时漂白、次氯酸盐漂白后再用Tween80后处理以及Tween80预处理加次氯酸盐漂白(分别以H/T、HT和TH表示)三种不同组合的漂白方式对纸浆白度、粘度及主要强度指标的影响进行了综合比较,结果发现Tween80在HT漂序中的助漂效果较好。在HT漂白中,当Tween80的用量为0.8%时,漂白浆的白度增加最多,粘度虽然有所下降,但仍大于对照次氯酸盐漂白浆,其抗张强度也较好,撕裂强度基本不变,但耐破和耐折强度有不同程度的下降。     

马尾松硫酸盐浆分段加碱氧脱木素性能的研究

研究了不同用碱量分四段加碱对马尾松硫酸盐浆氧脱木素的影响。研究结果表明:在总用碱量为4.5%时,分段加碱OOOO比两段氧脱木素OO能脱除更多的木素,木素脱除率达到68%～71%,而黏度仅降低26%～28%,纸浆的白度由27.1%提高到46.4%ISO。     

Alkyl ketene dimer modification of thermomechanical pulp promotes processability with polypropylene

Alkyl ketene dimers (AKDs) are known to efficiently react with cellulose with a dual polarity in their structure: a polar component and a nonpolar component. AKD of three different carbon chain lengths, 4, 10, and 16 carbons have been synthesized, and thermomechanical pulp (TMP) fibers were modified by them. The modification of TMP fibers with AKD resulted in an increased water contact angle, showing the presence of the AKDs on the TMP fibers and a new carbonyl peak in the IR spectra, suggesting modification of the TMP fibers with AKD groups. Calculating the Hansen solubility parameters of AKD and AKD conjugated to TMP in polypropylene (PP) indicates improved compatibility, especially of longer chain AKD and TMP AKD. The rheological studies of the composites showed that the AKD with the longest carbon chain decreases the melt viscosity of the PP-TMP-AKD composite, which combined with the shape and the color of the extruded composite filaments indicates improved flow properties and reduced stress build up during processing. The research findings demonstrate the ability of AKD to enhance the dispersibility and compatibility of natural fibers with PP.     

微波合成高吸水性树脂的研究

研究以微波辐射为辅助引发条件和反应的热源,利用纸浆纤维与单体丙烯酸在复合引发剂(硝酸铈铵和过硫酸铵)引发下进行非均相接枝共聚反应,合成高吸水性树脂.经过选择和优化得其最佳合成工艺条件:单体体积与纸浆干重比为10∶1,引发剂硝酸铈铵与过硫酸铵的用量为0.04mL和0.08mL,中和度为85%,在微波炉内引发(3min+3min)后,反应3min,所得树脂吸水率为1204g/g,吸盐水(0.9%NaCl)率为99g/g.     

某铝土矿尾矿管道输送试验研究

为了研究某铝土矿尾矿赤泥泵压管道输送特性,针对不同浓度尾矿赤泥进行了浆体流变特性研究,并采用DN200管道进行了环管试验。结果表明,该尾矿浆黏度大、屈服应力高,属触变性浆体; 矿浆浓度、输送速度对浆体管道输送摩阻系数的影响显著。该尾矿赤泥适宜的泵压管道输送浓度为25%,该浓度下尾矿浆体屈服应力11.45 Pa、动力黏度21.33 mPa·s。当流速2.0 m/s时,25%浓度尾矿浆的摩阻系数为0.05,管道内输送阻力损失为0.54 kPa/m。     

ZL聚苯颗粒外墙保温在小高层建筑中的应用

结合工程施工概况,对外墙保温施工技术进行了分析,介绍了ZL聚苯颗粒外墙保温系统的基本构造,并对其施工流程及关键材料的质量控制进行阐述,指出施工中应注意的问题,通过验算及实践证明,应用效果良好。     

Air bubble holdup in quiescent wood pulp suspensions

Air bubbles were injected into the bottom of a column filled with an aqueous suspension of wood pulp fibers to permit measurement of the probability that the bubbles escape the fiber network to reach the surface. Escape probabilities were measured as functions of bubble volume, pulp consistency (weight fraction of fibers), and pulp type. For a given consistency, larger bubbles rose through the column whereas smaller bubbles were held up in the fiber network. The higher the consistency, the greater the bubble diameter required for escape. The minimum buoyancy forces required for bubble escape were correlated with estimates of the yield stress of the fiber network.