Eco-friendly PVA/Kaolin Clay Coating for Barrier Paper

The resistance of wood-fiber paper to water, grease, and water vapor is usually attained by immersing the base paper in hydrophobic oil, laminating with a plastic or metal film, or the application of a barrier coating. Oil impregnation and the addition of films may make the paper difficult to recycle or persistent in the environment owing to their strong binding force and nondegradability. Environmental concerns have attracted worldwide attention to eco-friendly barrier coatings. In this study, degradable polyvinyl alcohol(PVA) and kaolin clay pigment were used to prepare coatings that were applied to a base paper. By measuring the barrier properties of the coated paper, including the water absorptiveness(Cobb60 value), Hercules sizing degree, oil resistance(Kit rating), and water vapor transmission rate(WVTR), an optimal coating formulation and process were proposed. To examine the barrier mechanism of the PVA/kaolin clay coating, we characterized the coating microstructures using a scanning electron microscopy(SEM) and a mercury porosimeter. The results showed that the Cobb60 value and water vapor transmission rate of the coated paper decreased by 61.4% and 98.6%, respectively, compared with the base paper, for a pre-coating weight of 0.98 g/m~2 and a top-coating weight of about 3.23 g/m~2. Furthermore, the Hercules sizing degree rose by a factor of 337.2, while the oil resistance(Kit rating) increased from 0 to 12. The optimum drying temperature for a wet coating layer was found to be 170℃, and the optimum weight ratio of PVA to kaolin clay in the coating was determined to be 50∶50. It was assumed that the PVA/kaolin clay coating improved the smoothness of the paper considerably and decreased the pore size by filling the pores on the paper surface and forming an even film, thus enhancing the paper barrier performance. The coated paper also exhibited good repulpability.     

二氧化硅对彩色喷墨打印纸性能的影响

In this paper,the effects of four sorts of silica with the particle size range of 4～10μm on coated paper properties and printing performance were studied.The results showed that the smaller particle size silica can provide the coated paper with higher density and contrast, better definition and good printing performance.     

Mechanism Analysis of Stiffness Improvement by Waterborne Epoxy Resin Surface Sizing Agent

Low-basis-weight paper lacks normal strength and stiffness.Waterborne epoxy resin could be employed with oxidized starch to improve paper stiffness through surface sizing.In this study,the mechanism of enhancing stiffness by adding waterborne epoxy resin was fully investigated.The results indicated that through surface sizing with epoxy resin,the paper thickness was preserved,whereas the elastic modulus increased significantly and the epoxy resin had positive impact on single fiber strength.A rigid resin layer and interpenetrating polymer network formed on the surface and in the inner layer of the paper,respectively.The formed resin layer and interpenetrating polymer network strongly supported the paper,leading to the improvement of the elastic modulus and stiffness.The stiffness improvement through surface sizing was mainly due to the formation of a fibrous composite layer and penetration of the sizing agent into the inner layers of the paper.The better the combination between fiber and sizing agent,the higher were the elastic modulus and the stiffness of the whole paper.     

Hard Winter Wheat and Flour Properties in Relation to Breadmaking Quality of Straight-dough Bread： Flour Particle Size and Bread Crumb Grain

Samples of 12 hard winter wheats and their flours that produced breads varying in crumb grain scores were studied for 38 quality parameters including： wheat physical and chemical characteristics; flour ash and protein contents, starch damage, swelling power, pasting characteristics, and flour particle size distribution; dough properties determined by a mixograph; and breadmaking properties for pup loaves （100g flour）. Only two parameters, the protein content of wheat and the granulation of flour, showed significant correlations with bread crumb grain scores. Protein content of wheat ranging 12.9%- 14.5% determined by an NIR method showed a weak inverse relationship （r =-0.61, p〈0.05） with bread crumb grain score. Flour particle size distribution measured by both Alpine Air Jet Sieve and NIR methods revealed that the weight wt % of particles less than 38 μ m in size and representing 9.6% - 19.3 % of the flour weights was correlated positively （r =0.78, p 〈 0.01） with crumb grain score, whereas wt % of flour particles larger than 125μm had an inverse relationship （r =-0.60, p〈0.05） with crumb grain score.     

Water and Oil Resistance of Special Paperboard for Petroleum Packaging

The influence of different coating formulas and times on the water and oil resistance of paperboard was studied.The water and oil resistance of paperboard coated with a modified butadiene-styrene copolymer latex and fluorinated anion grease-proof agent was better than that coated with modified butadiene-styrene copolymer latex,where the modified butadiene-styrene copolymer latex was used as the pre-coating substrate and the F1516 fluorinated grease-proof agent was used as the top coating material.By coating modified butadiene-styrene copolymer latex with 30％ solid content and F1516 fluorinated grease-proof agent with 24％ solid content,the oil resistance of paperboard could reach anti-oil grade 12 and the water resistance could increased by 98.64％ (compared with the base paperboard without any coating treatment).     

Heterogeneous Reactions between Starch and AKD under Solvent-free Conditions

Oxidized starch powder and cationic starch solution were reacted with alkyl ketene dimer(AKD) under heterogeneous conditions at 70℃ for 12 h.The AKD molecules reacted with starch hydroxyl groups to form β-keto ester linkages under the above conditions.The reaction products were separated into CHCl_3-soluble and CHCl_3-insoluble fractions.FT-IR spectroscopy,SEM,Xray diffraction,and TG-DTA analyses of the CHCl_3-insoluble fraction indicated that β-keto ester substituents were introduced to hydroxyl groups on the starch surfaces.The results indicated that hydrogen bonds between the starch molecules were disrupted under heterogeneous conditions upon heating.The activity and accessibility of hydroxyl groups were enhanced,as a result of which β-keto ester bonds were produced between AKD and starch.Based on these results,we speculate that the β-keto esters which existed in the sheets sized by AKD emulsions were generated by the reaction between AKD and starch.     

ZrB system by self-propagating

emperature synthesis (SHS) technique, and the effect of particle size of Zr powder on the SHS reaction in ZrB system was studied. The phase constituent of SHS product was investigated by X-ray diffraction analysis, a     

Preparation of Soybean Protein Concentrate with Mixed Solvents of Hexane－Aqueous Alcohol

Preparation of soybean protein concentrate with the mixed solvents of hexane-aqueous alcohol was studied in this paper.The optimum technology parameters were obtained by orthogonal tests.The results of experiments showed that the qualities of the product were good not only on taste of the product were good not only on tasted and color,but also on high solubility-NSI value was 48.80%.     

New Process for Extracting Oil and Starch from Tea Seeds

A new process for extracting oil and starch from tea seed was introduced. The new process included one special link compared with all of the processes used now for tea seed oil and starch production. The link was static fermentation by which oil bodies and starch were separated naturally from tea seeds. By the process, tea seed oil and starch which were in conformity with government standards about edible oil and starch were successfully produced with 16% and 8% of production rate, respectively. The new process has many advantages, such as more simple equipments, lower production cost and whole natural products, etc..     

Enhancement of Enzymatic Saccharifi-cation of Wheat Straw Residue by Ammonium Sulfite Pretreatment

Efficient utilization of wheat straw residue(WSR) from pulp mills is an important priority for the sustainable development of the pulp and paper industry. In this study, the effects of ammonium sulfite(AS) pretreatment with different AS charges(wt%) and pretreatment temperatures on the chemical composition and enzymatic hydrolysis of WSR were studied. The results revealed that more lignin was removed with the increase of pretreatment temperature and AS charge. The degradation of hemicellulose became severe at high pretreatment temperature, while cellulose remained stable during the pretreatment process. The enzymatic hydrolysis efficiency of pretreated WSR was increased and then decreased with the increase of the AS charge and pretreatment temperature. The AS charge exerts a stronger effect on enzymatic hydrolysis efficiency than the pretreatment temperature. Glucan and xylan conversion ratios up to 88.9% and 44.9%, respectively, were obtained. The highest total sugar conversion ratio was 67.0% when WSR pretreated with 16% AS at 165℃ was hydrolyzed with a cellulase loading of 40 FPU per gram of glucan.     

淀粉-脂肪酸复合物包覆改性硅藻土的制备及表征

采用淀粉-脂肪酸复合物对硅藻土进行包覆改性,研究了淀粉-脂肪酸复合物对硅藻土的包覆效果、改性硅藻土的留着率及抗剪切性能；采用扫描电子显微镜、Zeta电位仪、粒度分析仪对改性硅藻土进行表征。结果表明,淀粉-脂肪酸复合物可有效包覆硅藻土,淀粉沉积率达98%以上；与未改性硅藻土相比,改性硅藻土的Zeta电位高,抗剪切性能好；当改性硅藻土添加量为10%时,其留着率超过73%。     

脂肪酸不饱和度对高直链玉米淀粉-脂肪酸复合物结构和热性能的影响

本文研究了脂肪酸不饱和度对高直链玉米淀粉-脂肪酸复合物热性能、微观结构、粒径分布及Zeta电位的影响。结果表明,高直链玉米淀粉与脂肪酸形成复合物后热稳定性降低,且复合物的热稳定性随脂肪酸不饱和度的增加而降低;高直链玉米淀粉与脂肪酸形成复合物的结晶结构为V型,结晶度随着不饱和度的增加而减小;高直链玉米淀粉-脂肪酸复合物有两种存在形式,分别为颗粒表面凸起的球晶和嵌在颗粒表面的层状或絮状结构,后者存在形式随脂肪酸中双键个数的增加而减少;高直链玉米淀粉与脂肪酸形成复合物后淀粉颗粒变小,分散液稳定性增加。总之,脂肪酸不饱和度对高直链玉米淀粉-脂肪酸复合物的结构和热性能具有明显影响。     

造纸主要填料动态留着特性研究

用动态滤水仪研究了造纸填料与浆料的混合条件、填料、助留剂等因素对填料留着率的影响。研究表明,适当提高浆料的温度、延长浆料与填料的混合时间、适度的搅拌等有利于填料的留着,合适的填料复配也有利于填料的留着;助留剂可明显提高填料留着率,而且双元助留的效果好于单元助留。     

基于计算机视觉的纸张填料粒径分析方法

针对现有纸张填料粒径分析过程中使用的激光衍射法存在的缺点,提出一种基于计算机视觉的纸张填料粒径分析方法。将获取到的扫描电子显微镜图像进行预处理,去除噪声等影响统计粒径分布的因素,对图像中存在的填料颗粒粘连比较严重的部分采用改进的分水岭算法进行图像分割,进而利用快速连通域标记及欧拉数算法确定填料颗粒的粒径分布。最后将采用计算机视觉方法计算的填料颗粒粒径分布结果与采用激光衍射法得到的结果进行对比。在放大1500倍沉淀碳酸钙填料颗粒图像上的实验结果表明,采用计算机视觉方法计算的纸张填料粒径分布与激光衍射法测得的结果基本一致,中位径误差小于1%,累计粒度分布数达到85%时,误差在6%左右。     

酸碱两步法改性硅灰石的表征及对纸张性能的影响

研究了经酸碱两步法改性处理后的硅灰石形态结构变化及作为填料对纸张性能的影响。结果表明,先用H2SO4使硅灰石部分溶解,然后调节p H值至碱性,以使溶出物质再沉积到颗粒表面,形成疏松多孔包覆层,在保持硅灰石原有针状形态的基础上,实现了硅灰石颗粒表面结构的重建。与未改性硅灰石相比,改性后硅灰石的粒径有所增加,白度提高;其加填纸的白度高、松厚度好、强度降低少。虽然改性硅灰石在纸张中的留着率低于未改性硅灰石,但高于GCC填料。     

Interaction between PCC Filler and Cellulosic Fiber in Fiber/Filler Co-refining System

Mineral fillers are important for conserving raw fiber materials and reducing production costs in the paper industry. However, the increase in filler content will inevitably result in strength reduction, which limits the adding amount of filler in paper production. In this study, we designed a cellulose fiber/filler co-refining approach to improve the strength and optical properties of paper; moreover, the synergistic interaction between fibers and precipitated calcium carbonate (PCC) fillers in the co-refining process was investigated. Results of fiber separation and PCC particle size analysis showed that, compared with conventional refining, the content of fines increased, whereas the PCC particle size decreased. More importantly, composites were formed between the PCC and fines, which promoted strength improvement of paper. Physical tests show that the tensile index of paper with 15% PCC content increased by 22% compared with that of the paper filled by conventional method, whereas the brightness and opacity of paper improved by fiber/filler co-refining for a specified filler content. These findings provide a basis for the further development of co-refining filling technology.     

填料性能对加填纸施胶的影响及加填纸施胶效果的改善措施

综合讨论了填料的各种性能包括粒径和比表面积、亲水亲油性能、颗粒形态、碱度,以及填料与施胶剂之间的反应对纸张施胶效果的影响,并从填料的包覆改性技术、新型填料的开发研究、各种助剂的协同使用以及施胶剂和填料加入点位置的优化等几个方面总结了目前国内外解决加填纸施胶问题的相关措施.     

阳离子淀粉与碳酸钙预絮聚加填技术研究及生产应用

采用一定取代度的阳离子淀粉与碳酸钙进行预絮聚,通过控制预絮聚体的粒径,可获得具有良好稳定性的预絮聚体。将该预絮聚体用于文化用纸的加填,由于淀粉覆盖在碳酸钙表面,增加了其结合性能,纸张的表面强度及填料留着率均得到一定程度改善。填料留着率平均提高了24.2 个百分点。     

TEXTURAL PROPERTIES OF STARCH GELS FILLED WITH COLLAGEN AND CHITIN

Chitin and collagen powders were added as fillers to various starches (potato, sweet potato, kudzu, corn, wheat, and mung bean), heated at 100C for 10 min with stirring to make a hot paste and allowed to gel quiescently at 5C for 2 h in order to investigate the effects of the filler particle on the texture of the gels. The parameters of hardness, cohesiveness and adhesiveness were determined instrumentally and compared. The filler particles of collagen and chitin were effective in increasing hardness of corn starch gels but had no effects on hardness of the potato, sweet potato, kudzu, wheat and mung bean starch gels except at the lower starch concentrations. Cohesiveness was increased slightly in all starch gels by addition of collagen whereas chitin addition only increased the cohesiveness of sweet potato and mung bean starch gels. Collagen and chitin addition increased adhesiveness all of starch gels, but the intensity of the effect was most remarkable for collagen. The observed differences in effects was apparently due to differences in the interactions between starches and filler particles arising from differences in the surface properties of the filler particles.     

Preparation and Application of Microfibrillated Cellulose-modified Ground Calcium Carbonate

Microfibrillated cellulose(MFC) was first prepared by 2,2,6,6-tetramethylpiperidine-1-oxyl(TEMPO) oxidation pretreatment and mechanical grinding in the presence of a certain amount of ground calcium carbonate(GCC).The effects of GCC dosage and grinding concentration on the fibrillation were investigated.The obtained MFC was then added to the bulk GCC to form MFC-modified GCC fillers.The properties of MFCmodified GCC fillers were compared to those of the traditional GCC fillers.Results showed that the resulting fibrils became more uniform when the dosage of GCC was 10%~15% and the concentration of the suspension was 6.97%.Compared to traditional GCC,the average particle size of the MFCmodified GCC fillers was larger.Scanning electron microscopy images showed that GCC and MFC formed a bridge structure in the MFC-modified GCC fillers.In the process of papermaking,the MFC-modified GCC fillers decreased the drainage rate but increased the retention of fillers.The prepared papers filled with MFC-modified GCC fillers had higher tensile strength than those filled with traditional GCC fillers.