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1.
INTRODUCTIONMechanical pulp is the main furnish of newsprint. Unfortunately there are much more extractives in mechanical pulp than in other pulps such as Kraft. Extractives are often used to refer to the nonstructural components of wood and bark. Most extractives are organic solvents, including polyphenols, terpenoids, fats, waxes, organic acids, complex polysaccharides and nitrogenous compounds. The amount of extractives and their composition vary with respect to the botanical families…  相似文献   

2.
改性硅灰石在新闻纸造纸业中的双重环境效应   总被引:5,自引:0,他引:5  
介绍了一种新型矿物填料——改性硅灰石在新闻纸中的应用。样品采自云南省腾冲县,加工成1250目的超细纤维,其长径比为15左右,经化学改性处理,添加到脱墨纸浆中制作新闻纸。实验室手抄片和工业试验结果表明,改性硅灰石能极大地改善再生新闻纸的白度、不透明度和适印性。加入有10%~15%改性硅灰石的新闻纸(定量44~47g/m^2)具有高白度(58%~60%)、高强度(裂断长3800~4000m)和高不透明度(95%~97%),属高质量新闻纸。另一方面,由于改性硅灰石具有对油墨粒子、细小纤维和有机物有良好的吸附性,添加改性硅灰石的新闻纸在造纸过程中排出的废水易于处理,废水经简单沉淀后所含BOD和COD,以及重金属元素含量极低,达到综合排放国家一级标准。改性硅灰石在造纸业方面显现出保护森林和水体的双重环境效应,是造纸业中一种性能优秀的新型功能填料。  相似文献   

3.
1INTRODUCTIONLignin is one of the main three components in botany, and is one reproducible resource. It has three-dimensional network structure and more functional groups such as phenolic hydroxyl function group, alcoholic hydroxyl function group and methoxyl function group, so it has more reactivity and reaction active points [ 1, 2, 3, 4, 5, 6].Polyethylene oxide is applied in more fields as one kind of nonionic macromolecule. In papermaking industry, it is often used as dispersion agen…  相似文献   

4.
本文叙述了一种丙烯酸系高分子界面活性剂在新闻纸上采用外添型表面涂布法的过程、结果与意义。 研究结果表明,增强剂用量为纸重的0.4~0.5%时,纸的表面强度获得明显提高(IGT提高43.5%)。纸的机械性和印刷性良好。因此,这种高分子界面活性剂用作新闻纸等的增强剂,不论在施加方法或技术上都是可行的。同时,也说明这是解决用白杨等次等材代替白松制造符合技术要求的新闻纸的重要途径。增强剂的研究处于国外先进国家六十年代末的水平。本研究有新的进展,属于新型增强剂,其性能达到国内外同类先进产品的基本要求。  相似文献   

5.
本文分析了全杆红麻的物理特性及化学成份,并对全杆红麻硫酸盐法制浆进行了实验室小型试制。重点研究了全杆红麻漂白浆代替化学木装配抄普通新闻纸的可行性。  相似文献   

6.
INTRODUCTIONIn recent years, with the rapid development of paper-making technology[1], such as improvement of pa-per-machine speed, extensive use of high yield and recycling pulp, and more closed white water systems, the environment of papermaking has changed greatly and this has brought many problems, Such as water temperature increasing and water quality becoming worse, large amount of fines in pulp, and more and more aninonic trash in pulp and water. These causes drainability of pulp a…  相似文献   

7.
The regenerated cellulose fibers, made from wood pulp, have excellent physical properties like cotton fiber. Especially polynosic fibers can be mercerized by alkali, but conventional Viscose fiber can not be treated or mercerized by alkali. The paper studies on behavior of polynosic fibers treated by alkali, including physical properties, such as weight loss, tensile strength and elongation, and fiber structures properties. In this paper, on the basis of study on polynosic fibers treated by alkali, the conclusions were drawn as following. Firstly, polynosic fiber is good at alkali resistance. Secondly, the changes of fiber structure and physical properties begin declining at 5 wt% NaOH concentration and reverse changes take place at 10 wt%.  相似文献   

8.
本文通过广角 X 射线衍射、纤维力学性能的测定、扫描电镜方法等研究了在不同浓度硫酸及氢氧化钠水溶液、不同处理温度和不同时间条件下,具有不同预氧化程度的预氧化腈纶短纤维耐酸碱的基本行为。探讨了预氧化腈纶短纤维在酸碱水溶液作用下,力学性能下降的机理及纤维预氧化程度对耐酸碱性的影响。  相似文献   

9.
Microparticle retention system, developed lately, mainly consists of cationic polymers and anionic inorganic substances, such as Hydrocol system consisting of cationic polyacrylamide/modified bentonite and Compozil system[2] with cationic starch/anionic silica sol. The principle of electrostatic interaction has been adopted for these systems. Whereas if there are plentiful anionic trashes in systems, their efficiency will not embody primely. Although anionic trash catcher (ATC) could be adde…  相似文献   

10.
将PET与共聚酯共混纺制中空共混纤维,经碱处理后形成多孔的高吸水涤纶。本文通过X—射线衍射仪,分光光度计,扫描电镜和热收缩仪等测试对高吸水涤纶纤维和共混纤维的结构和染色性进行了研究,目的在于探索高吸水涤纶染色机理。研究结果发现高吸水涤纶纤维与共混纤维相比较,不仅具有许多微孔,而且结晶度高,晶粒尺寸大,单位非晶体积大,非晶区结构紧密;高吸水涤纶的上染量与保水率呈指数关系。由此推论高吸水涤纶上染量高主要是由于纤维中微孔的吸附染料作用。  相似文献   

11.
荨麻纤维可纺性能的分析研究   总被引:3,自引:0,他引:3  
探讨天然野生植物纤维--荨麻纤维的可纺性.测试了荨麻纤维的物理机械性能,如长度、细度、强度和柔软度等指标,分析了荨麻纤维在纺织加工过程中的纺纱性能;采用不同的纺纱系统和纺纱工艺,对其可纺性作了进一步的研究.结果表明,由于荨麻纤维的主体长度较短,细度和长度离散较大,纯荨麻纤维无法成纱,与棉混纺时可以成纱;但成纱质量并不理想.为开发野生荨麻资源提供参考.  相似文献   

12.
INTRODUCTIONIn papermaking industry, microparticle retention aid systems have been widely accepted in past decade because of their simultaneous improvements on retention and drainage but with no sacrifice in formation compared with conventional polymer retention systems. Polyacrylamide/bentonite is one of the typical microparticle retention aid systems,in which highly anionic charged bentonite is used as the microparticle component. The flocculation mechanism of this microparticle retentio…  相似文献   

13.
为了实现连续规模化生产以及碳纤维在尼龙6复合材料中的均匀分布,采用了长径比为32:1的SLJ-35B型双螺杆挤出机.结果显示碳纤维在复合材料中分布非常均匀,碳纤维平均长径比约为20:1;在潮湿环境下与纯尼龙相比,碳纤维增强后的尼龙6复合材料各项性能的稳定性明显增加;扫描电镜照片显示碳纤维与尼龙基体强化学耦合显著提高了复合材料的整体粘结性.  相似文献   

14.
本文对循环负荷处理前后的锦纶、丙纶和粘胶长丝的力学性能进行了测定,并讨论了纤维应力松弛和弹性回复性能间关系。试验分析表明:不同类型纤维经处理后,由于纤维内部结构变化不同,引起的力学性能改变也有着明显的差别。  相似文献   

15.
Generally there are three kinds of substances used as negative-ion generator in textiles, natural silicate minerals (ceramic/tourmaline), natural rare-earth minerals and natural sediment with ultra-fine pores. Based on different additive, the mechanism of negative-ion generation is largely divided into three kinds, the piezoelectricity and pyroelectricity of tourmaline crystal, air ionization caused by low-level radiation and breaking up of the clusters of moisture in air when going through the ultra-free pores of natural sediment. In this paper, the negative-ion generating properties of natural fiber fabrics-cctton, wool, silk and linen were first proposed. By some kind of physical stimulation, rubbing or vibrating, natural fiber fabrics without any additive could also emit negative ions. Considering that the piezoelectric effect was observed in wool fibers, silk fibers and cellulose fibers, the piezoelectricity was studied as a mechanism of negative-ion generation of natural fiber fabrics. Another possible mechanism was the tribeelectricity produced by the sense of ntbbtng or vibrating and tip discharge of hairiness. The Final experiment results verified that the latter would be the main reason, and the electrolytic dissociation of moisture was also contributing to negative-ion generation.  相似文献   

16.
INTRODUCTIONRecently with the high speed, large-scale develop-ment of papermaking, in the manufacture of paper and paperboard conventional single and dual reten-tion and drainage systems cannot obtain satisfying re-tention and drainage. So in 1980 microparticulate systems appeared. Because of its superiority such as good retention effectiveness on fine and chemicals, improving drainage and paper formation, reducing waste water and enhancing the concentration of white water for good recover…  相似文献   

17.
A new technique was proposed to enhance the adhesive strength of ultrahigh molecular weight polyethylene (UHMWPE) fibers. Polar polymer was implanted into UHMWE gel fibers during extracting process and can then be trapped on the surface of the fibers after subsequent ultra-drawing. The physical and chemical changes in the fiber structure were examined with scanning electron microscopy (SEM) and Fourier transform infrared (FTIR) spectroscopy. The mechanical and interfacial adhesion properties of UHMWPE fibers were investigated with tensile testing. The results showed that there were polar groups on the smface of pretreated UHMWPE fiber. The interracial shear strength of UHMWPE fibers with epoxy resin was greatly improved without sacrificing the excellent mechanical p~perties of fibers. After pretreated with ethylene/vinyl acetate copolymer (EVA), the shear strength of the interface between fiber and epoxy resin increased from 1.06 to 2.49 MPa, while the integrated mechanical properties d the pretreated UHMWPE fibers were still optimal.  相似文献   

18.
在朴素贝叶斯分类的基础上建立了一种增强型分类器系统,并在对1997~2002年夏季青藏高原上MCS(Mesoscale Convective System)进行自动追踪的基础上,对MCS的移动方向与其周边环境物理量场的分布特征进行了分类研究.进而,将分类结果与决策树、人工神经网络分类方法进行了比较.研究表明,与其他分类方法相比,使用增强型的贝叶斯分类器预测MCS的移动路径具有较好的效果,这为揭示高原上MCS的移动规律、提高长江中下游地区灾害天气预报的准确率提供了一种有效的方法.  相似文献   

19.
INTRODUTIONWaste paper is an important recyclable resource. The problems that are concerned with resource, energy and environment can be solved effectively by recycling of the waste paper. In the past decade, countries all over the world have paid great attention to the recycling of waste paper, so its recycling ratio has been increasing year and year. The technologies for waste paper recycling have also been developed and modified. The production and varieties of paper and paperboard mad…  相似文献   

20.
The enzymatic deinking and fiber modification of old newsprint (ONP) with several cellulases and xylanase were investigated and the suitable enzyme candidates were selected for ONP deinking in this paper. The results demonstrated that the cellulases and hemicellulases could significantly improve the deinking efficiency and fiber modification.Moreover, the synergistic effects of Novozym342 and xylanase (HC) can further enhance the deinking performance, reduce the dirt count and improve the brightness of resulting pulp. Additionally, compared to deinked pulps, obtained from conventional chemical materials, enzymatically deinked pulps had better bleachability, and the brightness of the bleached pulp reached 59.1% ISO, 9% ISO higher than the unbleached pulp.  相似文献   

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