STUDY OF CARBOXYL METHYL STARCH ON PAPER STRENGTH

A novel starch derivative--carboxyl methyl starch (CMS) was investigated in this paper. Through a series of experiments, the results showed that CMS has considerable effect on paper strength as internal additive, and the better technology conditions are as follows: pH=7.0, CMS dosage is 1.0% (on o.d. pulp), mixing time is 45min and drying temperature is 105℃.

WET STRENGTH PAPER REPULPING: LABORATORY EVALUATION

The recycling of wet strength papers in a normal recycling mill is often troublesome due to the severe operating conditions required to defibre wet strength papers. The various methods are presented which will quickly allow mills to determine the most effective pulping aids to use when repulping wet strength papers. The repulping of wet strength paper with inorganic chemicals was investigated in the laboratory. The effects of major variables, that is, repulping time, pulp consistency, soaking time, temperature, and reactant concentration in the repulping stage were examined using Plackett-Burman design. The repulping time was the most crucial & influential process variable affecting repulping characteristic and formation related properties. The more significant repulping process variables affecting pulp yield were repulping time, soaking temperature and pulp consistency whereas for formation index and feature size, repulping time, pulp consistency, soaking temperature and time were the more important variables. The formation index is increased by an increase in repulping time, pulp consistency and soaking time whereas the feature size is decreased by an increase in repulping time, soaking temperature and pulp consistency. The formation index and the rejects were more sensitive to changes in process variables than were the feature size or the pulp yield. The pulp recycled from wet strength waste paper had good physical strength properties.

Cationized Melamine-formaldehyde Resin for Improving the Wet Strength of Paper

In this work, melamine-formaldehyde resin was cationized by adding modifiers so that the fibers closely bonded to improve their usability and the wet strength of paper was greatly improved. Triethanolamine and dimethylamine were added to modify the melamine-formaldehyde resin,respectively.The mechanism of the cationized resin was explored and the possible chemical reactions were deduced. It was concluded that,with the use of triethanolamine,the most optimum product was obtained by hydroxymethylation for 30 min with a temperature of 85℃ and p H of 9. 0 where n( melamine) ∶ n( formaldehyde) ∶ n( methanol) ∶ n( triethanolamine) was 100 ∶ 330 ∶ 450 ∶ 15. With the combined use of dimethylamine and methanol,the optimal product was acquired by condensation for 30 min at a temperature of 50℃ and p H of 2. 0 at melamine, formaldehyde, methanol, and dimethylamine molar ratio of100∶ 330∶ 350∶ 20. With the only use of dimethylamine,the optimal product was obtained by condensation at melamine,formaldehyde,dimethylamine molar ratio of 100∶ 330∶ 10. The wet tensile strength of fruit-bagging paper was improved by adding cationized melamine-formaldehyde resin. The zeta potential,charge density,and conductivity of the melamine-formaldehyde resin were also studied.

沉析纤维尺寸和含量对间位芳纶纸性能的影响

使用不同目数的筛网对自制的Z沉析纤维进行筛分,将得到的不同尺寸的沉析纤维与间位芳纶短切纤维按一定质量比配抄成纸,制备间位芳纶纸;通过红外光谱、X射线衍射、扫描电镜及热失重、动态滤水分析对自制的Z沉析纤维的化学结构、热性能、动态滤水性能进行表征,并与进口的J沉析纤维对比;研究了沉析纤维的尺寸和含量对间位芳纶纸性能的影响。结果表明:Z沉析纤维与J沉析纤维均为膜状结构,化学结构基本一致,动态滤水性能及热性能相当;经30目或50目的筛网筛分后的沉析纤维可以与短切纤维更好地抱合,间位芳纶纸的抗张强度、断裂伸长率、撕裂度、击穿强度均达到较大值;间位芳纶纸的撕裂度随沉析纤维含量的增加逐渐降低,间位芳纶纸的抗张强度、断裂伸长率、击穿强度随沉析纤维含量的增加呈现先增后降的变化趋势,当沉析纤维质量分数为55%时,间位芳纶纸的抗张强度、断裂伸长率、击穿强度均达到最大值,分别为3.0 kN/m、5.50%、18.7 kV/mm。

基于纸张纤维特征的纸页抗张强度智能模拟及预测研究

对纸页抗张强度进行智能模拟,有助于更好地对某种纸页的性能进行分析甚至预测。基于此,针对现有纸页抗张强度模拟方法的缺陷进行总结,认为现有典型Page分析模型存在客观性分析不足等问题,结合偏最小二乘法、支持向量机等构建了一种基于造纸纤维特性的纸页抗张强度智能模拟模型,借助该模型对某种典型纸页的性能进行模拟分析。测试结果表明:该模型能够高效、准确地对纸页抗张强度进行预测,与传统模型相比具有更强的实用性。

烟用商标纸与胶黏剂的相互作用及其对粘合强度影响

对典型烟用商标纸和包装胶性能进行分析,研究了胶黏剂在商标纸粘合部位表面液滴的接触角和宽度的变化,探讨了上胶开放时间对商标纸-包装胶组合粘合强度的影响。结果表明,包装胶滴加到商标纸表面上时,无论印刷面还是非印刷面,随着时间的延长,接触角不断减小,液滴宽度不断增加,液滴接触角和宽度达到平稳的时间不同,液滴接触角的降低是扩展和渗透共同作用的结果,而液滴宽度变化只和扩展有关。不同的商标纸-包装胶组合,液滴接触角和宽度的变化不同,上胶开放时间窗口也不同,与胶黏剂的黏度和固含量及商标纸的扩展和渗透性有一定的联系。水对商标纸的润湿性与胶黏剂明显不同,不宜采用水在纸张表面的润湿性来判断胶黏剂的行为。

短切纤维特性对间位芳纶纸电气绝缘性能的影响

本文研究了短切纤维特性对间位芳纶纸击穿强度、电导率、陷阱特性和力学相关性能的影响。结果表明,在参照样品(直径为25μm、长度为6 mm、结晶温度为300℃、沉析纤维与短切纤维的配比为7∶3)的基础上,纤维直径增加至45μm会降低沉析对短切纤维的包覆程度,诱发界面孔隙,芳纶纸的击穿强度和拉伸强度降幅可达16%和24%;纤维长度增加至18 mm,会造成短切纤维翘曲并形成“硬质”界面,击穿强度降幅可达63%,拉伸强度则无明显变化;结晶温度降低至230℃,会降低短切纤维结构稳定性,导致其热压熔融,击穿强度和拉伸强度降幅可达36%和50%;当短切纤维配比增加时,芳纶纸的击穿强度随致密度呈先升后降趋势,拉伸强度则随短切纤维含量的增加单调递增,体现了短切纤维对芳纶纸稳定成型的必要性和过量短切纤维对绝缘的削弱作用。此外,低击穿强度芳纶纸会呈现电导率提高和电荷陷阱浅化的现象,可作为芳纶纸绝缘性能判别的参考指标。

高性能内燃机用滤纸的制备及其对性能的影响

采用高强高模聚乙烯(UHMWPE)纤维与针叶木浆混抄,制备具有力学性能高、疏水性好和透气性适当的内燃机用滤纸。通过探讨原纸制备工艺、树脂浸渍和热压工艺对滤纸性能的影响,确定试验条件下的最佳参数,并采用相关手段表征了滤纸的力学性能、热稳定性能、孔径大小以及疏水性能。结果表明:在试验条件下,当UHMWPE纤维与针叶木浆的质量比为8∶2、针叶木浆打浆度为22°SR、分散剂PEO和增强剂CPAM相对于绝干浆的质量分数分别为0.5%和0.1%、热压时间为15 min、热压压力为10 MPa、热压温度为140℃时,制备的内燃机用UHMWPE滤纸性能最佳,其中,滤纸抗张指数为50.28 N·m/g,耐破度为503.55 kPa,接触角为123.52°且1 min内不渗透,熔点提高至155℃。

PAE湿强剂中氯丙醇含量对纸张水提取液中氯丙醇含量的影响

为检测PAE湿强剂中氯丙醇的含量,本研究建立了气相色谱-质谱联用法(GC-MS),检测PAE湿强剂中1,3-二氯-2-丙醇(1,3-DCP)与3-氯-1,2-丙二醇(3-MCPD)的含量,并进行了方法学验证,同时探究了PAE湿强剂中氯丙醇含量与纸张水提取液中氯丙醇含量之间的关系。本研究对4批次某款湿强剂进行检测,发现随着湿强剂制造工艺的改进,1,3-DCP与3-MCPD的含量均有明显的下降。调整湿强剂和助留剂的添加量,抄造不同批次的纸张,同时测定纸张水提取液中的氯丙醇含量与纸张的抗张强度。结果显示,纸张水提取液中的氯丙醇含量与湿强剂中氯丙醇含量呈正相关关系,与湿强剂添加量成正比;在助留剂实际添加量超过厂家推荐添加量的情况下,纸张水提取液中的氯丙醇含量与助留剂添加量无明显关系,但会导致纸张湿、干抗张指数下降。

GPAM增强剂在生活用纸中的应用实践

竹浆作为木浆的替代品已在生活用纸生产中得到广泛应用,但其成纸强度低于木浆。为保证成纸强度,稳定生产运行,本文从实验室小试及生产应用两方面对增强剂GPAM应用进行分析评价。结果表明,GPAM不仅可提升成纸的干抗张强度,还能提升成纸的湿抗张强度、降低湿强剂的用量。

匀度指数对碳纸原纸强度与孔隙特性的影响研究

本研究以碳纤维为原料,通过改变分散剂种类制备具有不同匀度性能的碳纸原纸,考察了碳纤维浆料的分散稳定性及其均匀性变化规律,探讨了匀度指数与透气度、抗张强度、孔隙率等指标之间的关系。结果表明,与单一APAM、TOCNs和PU分散剂相比,质量分数0.1%APAM和1.0%PU复合的分散剂体系制备的碳纤维浆料分散稳定性和均匀性得到改善,该复合分散剂制备碳纸原纸匀度指数最好,为10.32。随着匀度指数的减小,碳纸原纸厚度偏差从21.76 mm降至0.96 mm,抗张强度从0.15 kN/m增加到1.68 kN/m,孔隙率从93.5%下降到90.5%,透气度从1 658.9 L/(m^(2)·s)下降到1 171.5 L/(m^(2)·s)。

浸渍热压工艺对碳纸结构性能的影响及机理研究

本研究通过探究碳纸浸渍和固化过程中酚醛树脂的分布及形态结构,研究浸渍热压工艺对碳纸性能的影响。结果表明,当浸渍时间为4 min,浸渍液浓度为11%时,预固化后碳纸中所含的树脂最多,浸渍量可达154.9%。当热压温度为160℃,热压时间为20 min,热压压力为3.0 MPa时,制备的碳纸热压纸性能最好,电阻率仅27.1 mΩ·cm,抗张强度达103.9 N/cm。

WATER-BASED BINDERS USED IN PROCESS FORMAKING AUTOMOBLE FILTER PAPER

A method for making a automobile filter which includes impregnating a filter paper with a cross-linkable binder composition is discussed in the article. The water-based binder comprises a latex containing 80 wt% acrylic acid in the latex solids, and 20 wt% melthyl methacrylate, the binder also contains 5 parts of a cross-linking resin per 100 weight parts of latex solids and 5% parts of catalyst for the cross-linking resin based on the weight of the cross-linking resin. 4 wt% water-based polymer emulsion, on a solids basis, which is used to impregnate filter paper and rigidify it. Such impregnated filter paper has good dry and wet tensile strength and stiffness. The method has no impairing to the environment.

Preparation of Polysulfonamide Porous Paper and Its Adsorption Properties

Three-dimensional porous paper was prepared by using polysulfonamide (PSA) fiber and pulp as the raw materials. The effect of PSA fiber to pulp ratios on the mechanical strength and adsorption properties (using methyl orange and rhodamine B dyes in their aqueous phase) of the paper were studied. The results showed that the tensile strength and elongation characteristics decreased as the PSA fiber to pulp ratio increased, while the tear strength increased. PSA paper showed good adsorption performance for both methyl orange and rhodamine B, with the adsorption process conforming to the pseudo-second-order and Langmuir isotherm models, indicating monolayer chemical adsorption. The study has provided an improved theoretical and scientific basis for the further development and application of PSA paper.

芯纸厚度对瓦楞纸板边压强度的影响及模拟

目的 针对瓦楞纸板的强度设计未进行系统研究的问题,通过改变楞纸的厚度研究瓦楞结构的改变对其边压强度的影响。方法 对WH81287型号的五层BE型瓦楞纸箱进行取材,对瓦楞纸板进行边压强度(Edge Crush Test,ECT)试验,通过试验数据验证有限元软件中模型的可靠性,并在Matlab中对数据进行分析,通过调整瓦楞芯纸厚度以用于瓦楞纸板的强度设计。结果 在边压强度的试验中,根据实验数据可以得到,瓦楞纸板的平均变形量为0.824 0 mm,最大边压力均值为1 041.2 N。在仿真分析中,B瓦厚度趋近于0.210 0 mm时,瓦楞纸板的最大变形量均趋近于1.195 0 mm,最大等效应变均趋近于0.1150,最大等效应力趋近于23.5000MPa;在B瓦厚度增加或减少过多时,瓦楞纸板的最大变形量呈现逐渐增加的趋势,最大等效应变与最大等效应力出现陡增或骤减。结论 通过不同楞纸厚度与各参数之间的函数曲线图,找到了瓦楞纸板的最优参数,其最大变形量最小,最大等效应力、应变均较小且趋于稳定,这为实际应用中瓦楞纸板的强度设计提供了指导,提升了瓦楞纸板楞纸结构的设计效率。

Effect of Waste Paper Fiber on Properties of Cementbased Mortar and Relative Mechanism

The aim of this work was to investigate the effect of waste paper fiber on the properties of cement-based mortar and the relative mechanism. The cement-based mortars with various contents and mixing way of waste paper fibers were prepared and the slump flow, setting time and strength developments of all mortars were tested. Besides, Ca(OH)_2 content in hardened pastes at different ages and the microstructures of all mortar at 90 d were observed by scanning electron microscopy. The experimental results showed that in the process of mixing, more superplastizier was consumed to maintain the workability because of the absorption of water and superplastizer on waste paper fiber. With more waste paper fiber being added, longer setting time is available for the pastes with it because of the carbohydrate dissolving and its retarding to the cement hydration. Waste paper fiber is adverse to the early and later strength of cement-based mortar, but it increases the mortar strengths at 7 and 28 d. The strength, Ca(OH)_2 content and microstructure are related to the content and mixing way of waste paper fiber. Waste paper fiber helps produce the Ca(OH)_2 at 7 and 28 d, but this case is reverse at ages of 1 and 3 d. Overall, waste paper fiber leads to the appearance of more pores in the hardened paste. However, it increases the toughness of cement-based mortar.

等离子体羟基化改性纳米SiO_(2)粒子对绝缘纸绝缘特性的影响

在绝缘纸中掺杂纳米粒子,可通过其对载流子的限制来提高绝缘纸的绝缘特性。然而,纳米粒子的高比表面积和表面活性易形成“团聚”,导致纳米粒子聚集处易产生局部放电和击穿。为了有效抑制纳米粒子团聚、进一步提高绝缘纸的绝缘特性,利用介质阻挡放电(DBD)等离子体对纳米SiO_(2)粒子进行羟基化改性,增加纳米粒子表面羟基数,并通过氢键与硅烷偶联剂分子发生偶联作用从而桥接在绝缘纸基体上,改善了纳米粒子和绝缘纸的兼容性,从而改善其团聚,并采用原位聚合法制备了掺杂纳米SiO_(2)粒子的纤维素绝缘纸。利用X射线光电子能谱仪(XPS)、扫描电子显微镜(SEM)、傅里叶红外光谱仪(FTIR)、比表面及孔隙度分析仪(BET)结合滴定法等手段表征了等离子体改性前后纳米SiO_(2)粒子表面化学组分、微观形貌、官能团及接枝羟基数目的变化规律。并考察了等离子体处理条件及改性步骤对绝缘纸击穿场强和体积电阻率的影响。研究结果表明,纳米SiO_(2)粒子经等离子体羟基化改性后表面氧元素含量及羟基吸收峰显著增强,其在绝缘纸中的分散性得到明显改善。当等离子体改性时间为5 min、空气相对湿度为75%时,纳米SiO_(2)粒子表面接枝的羟基数目达到最高。掺杂了3wt%等离子体羟基化改性的纳米SiO_(2)后,绝缘纸的直流击穿场强和体积电阻率达到18.35 kV/mm和17.45×10^(9)Ω·m,较掺杂了未改性纳米SiO_(2)的绝缘纸分别提高了10.7%和19.4%,较未掺杂纳米SiO_(2)粒子的绝缘纸提高了52.3%和106.2%。

横纹卷烟纸强度自然衰减浅析

通过测定横纹卷烟纸在不同放置时间的强度指标发现,随着卷烟纸放置时间增加,其强度性能发生衰减。为满足现代高速卷烟机的生产需求,这就需要我们加强对卷烟纸强度衰减规律及原因的研究,并采取相应的措施。

Aging Effect on Characteristics of Oil Impregnated Insulation Paper for Power Transformers

This paper deals with experimental investigations of the electrical and physical properties of oil impregnated insulation paper for power transformers at different temperatures. The ac breakdown voltage, tensile strength and water content of insulation papers impregnated in mineral oil for different time periods were investigated. The effect of insulation paper thickness on the electrical and mechanical properties has also been studied. The results showed that the breakdown voltage and the tensile strength decreased with increasing the time of immersion of insulation paper in oil at room temperature, at 5℃ and at -12℃. Also, the thermal aging effect on the characteristic of insulation paper has been studied. It was found that high temperatures affect the breakdown voltage and the tensile strength to a great extent.

育苗纸在高速纸机上的生产实践

我国育苗纸通常以圆网或长网等小型纸机生产。本文首次采用大型夹网纸机生产育苗纸,从实验室小试与实际生产等方面探讨了高速夹网纸机生产育苗纸过程中的质量指标、工艺条件及生产控制要点。结果表明:降低纸机上网浆料浓度、优化干部烘干曲线及压光机压力,使育苗纸匀度、强度及紧度等达到工艺质量要求;产品质量指标达到了企业标准的要求,满足了育苗的使用要求。