Effects of Some Additives on the Adhesion of Polyacrylamide Sizes to Fibers

IntroductionPolyacrylamide ( PAM) size is one of the sizeingredients that are commonly used in conventionalfor mulations for warp sizing and paper making .It has theproperties of adhering to fibers and can be capable ofholding fiber together by surface attachment . Comparedwith starches and polyvinyl alcohols , PAM possesses suchcapability as excellent adhesion to cellulose fibers . Thiscapability ,however ,is not due to chemical valence ;but isdeveloped only through hydrogen bonds and Van …     

Effect of Starch Dodecenylsuccinylation on the Adhesion and Film Properties of Dodecenylsuccinylated Starch for Polyester Warp Sizing

A series of dodecenylsuccinylated starches（ DSSs） with different degree of substitution（ DS） were prepared via the esterification of dodencenylsuccinic anhydride with hydrolyzed cornstarch in aqueous dispersion for investigating the influences of starch dodecenylsuccinylation upon the performances such as apparent viscosity and surface tension of starch paste, film behaviors,and adhesion to fibers for warp sizing. It was found that the dodecenylsuccinylation was able to reduce the surface tension of cooked starch paste and enhance the adhesion of starch to polyester fibers. It was also capable of depressing the brittleness of native starch and improving the mechanical behaviours such as breaking elongation and work-to-break of starch film. Initial increase in DS level of dodecenylsuccinylation enhanced these positive effects,while excessively increasing the level resulted in marked reduction in tensile strength of starch film and significant decrement in reaction efficiency. X-ray diffraction patterns of starch films showed the dodecenylsuccinates derivatized onto the backbones of starch depressed the degree of crystallinity of starch film. Based on the paste behaviors, adhesion, and film properties, the dodecenylsuccinylation level is recommended in a range of 0. 015-0. 025 for sizing polyester warps.     

Effect of Carboxymethyl Starch as Stabilizer for Increasing the Stability of Warp Sizing Pastes

The influences of carboxymethyl starch used as stabilizer upon the stability of native cornstarch-polyvinyl alcohol blend pastes for warp sizing have been investigated. The effect of the modified starch on the paste stability was evaluated in terms of the initial demixing time and the volume percentage of separated starch. The carboxymethyl starch with a series of different degrees of substitution was prepared in ethanol dispersion by varying the amount of monochloroacetic acid reacted with refined native cornstarch. The paste stability strongly depends on the modification extent and amount of carboxymethyl starch used, and on native starch content in the paste. Increase in the modification extent and/or the amount of the modified starch effectively retards the phase separation and reduces the separation extent of native cornstarch-polyvinyl alcohol blend pastes. Moreover, the mechanism and favorable modification extent of carboxymethyl starch for enhancing paste stability are also investigated and disc     

Study on the Preparation of Allyl-modified Starch in Isopropyl/Water Medium for Warp Sizing

A new method for the pretreatment of starch by etherification was developed to eliminate the problems of lower grafting efficiency associated with the preparation of starch graft copolymers as warp sizing agents. The etherification of starch with allyl chloride was investigated in order to effectively enhance the reaction efficiency. The tecimological variables of the reaction considered for evaluating the etherification included sodium hydroxide amount, water content in water-isopropyl alcohol medium, allyl chloride concentration, reaction temperature and reaction time. The experimental result demonstrated that the variables considered showed evident effect on the reaction efficiency. For the etherification, a condition of 20% for the water content, 1.5：1 for the molar ratio of sodium hydroxide to allyl chloride, and at 30℃ under 24 h reaction is sufficient to retain the reaction efficiency above 50%. Furthermore, a contrast test demonstrated that the graft efficiency can be increased with the etherification pretreatment.     

Starch Modifications to Improve the Paste Stabilities Both in Phase and Viscosity for Warp Sizing

Introduction Starchandpolyvinylalcohol(PVA)arecommonly usedtogetherinablendedpasteforsizingvarious synthetic/celluloseblendspunyarns.Tousestarch satisfactorily,thehotpasteofstarchmusthavesufficient viscositystabilitysinceunstablestarchpasteinviscosity tendstobecomethinning,thatis,theviscositydecreases withdelayoftime.Variationinpasteviscosityfluctuates sizeadd on,whichisseriouslyharmfultothequalitiesof sizedyarns.Tocompensateforthedefect,cross linking treatmentsareoftenappliedtostarchsizesto…     

丙酸酯变性淀粉浆料的研究

采用丙酸酐作为酯化剂,通过改变丙酸酐对玉米淀粉的投料比,制备一系列具有不同取代度(DS)的丙酸酯淀粉,以研究淀粉丙酸酯化变性程度与浆渡黏附性能和浆膜性能的关系,并通过与醋酸酯化变性的对比,来评价淀粉丙酸酯化淀粉的上浆性能.实验结果表明:淀粉丙酸酯化变性能够显著改善淀粉对涤纶纤维的黏附性能,提高淀粉浆膜的断裂伸长率和耐屈曲次数,降低浆膜的磨耗;随着取代度的增加,丙酸酯淀粉时涤纶纤维的黏附力先增大后减小,当取代度为0.019时,黏附力达到最大;相近取代度下,丙酸酯淀粉的浆膜性能及对涤纶纤维的黏附性能均优于醋酸酯淀粉.作为浆料使用的丙酸酯淀粉,其变性程度不宜过大.     

新型高黏着力化学浆料的合成及应用

以乙酸乙烯酯、苯乙烯、丙烯酰胺、丙烯酸丁酯、丙烯酸为单体,以十二烷基苯磺酸钠等配制成的复合乳化剂为乳化剂,过硫酸铵为引发剂,采用自由基乳液聚合法,合成了高性能化学浆料,并进行了浆料性能测试及浆纱试验.结果表明：通过优化单体配比所合成的浆料具有高黏着力、低吸湿、低再黏等性能,与P24变性淀粉配合,作为主浆料取代PVA上浆,其浆纱质量好,织造效率高,布面质量好,得到用户的好评.     

糊化阳离子淀粉用于经纱上浆的研究

介绍了糊化阳离子淀粉的制备方法，通过对其浆液性能和浆纱质量的测试，证明该浆料性能优良，具有高浓低粘、抗静电的特性．在细特纯棉、涤棉纱上浆中，不仅取代ＰＶＡ的量大幅度增加，而且浆纱质量有了明显的提高．     

Effect of Electrolyte Impurities within Starch on the Adhesion of Quaternary Ammonium Starch to Fibers

Influences of some electrolyte impurities within starch and starch cationization on the adhesion of quaternary ammonium cornstarch to cotton and polyester fibers were investigated.The electrolytes considered included NaCl,Na2SO4,NaH2PO4 and Na2HPO4.The adhesion to fibers was evaluated in terms of maximum strength and work-to-break of the roving sized with the starch pastes containing electrolytes.It was found that the cationization showed a positive effect on the adhesion to both fibers whereas the electrolytes gave an adverse effect and reduced the adhesion.The adverse effect depends on the type and amount of electrolytes.The influence of electrolytes on the adhesion can be ranked in a series of NaH2PO4 > Na2HPO4 > Na2SO4 > NaCl.The adhesion enhances as the modification extent increases and the electrolyte content decreases.Furthermore,the adverse effect can be compensated by the positive effect of the starch modification even at a low modification extent.If the electrolytes are fully eliminated,the cationic starch can increase the adhesion strength by more than 10% for both fibers.     

Effect of Electrolyte Impurities within Starch on the Adhesion of Quaternary Ammofiium Starch to Fibers

Influences of some electrolyte impurities within starch and starch cationization on the adhesion of quaternary ammonium cornstarch to cotton and polyester fibers were investigated. The electrolytes considered included NaCI, Na2SO4, NaH2PO4 and Na2HPO4. The adhesion to fibers was evaluated in terms of maximum strength and work-to-break of the roving sized with the starch pastes containing electrolytes. It was found that the cationization showed a positive effect on the adhesion to both fibers whereas the electrolytes gave an adverse effect and reduced the adhesion. The adverse effect depends on the type and amount of electrolytes. The influence of electrolytes on the adhesion can be ranked in a series of NaH2PO4〉 Na2 HPO4〉 Na2SO4 〉 NaCl. The adhesion enhances as the modification extent increases and the electrolyte content decreases. Furthermore, the adverse effect can be compensated by the positive effect of the starch modification even at a low modification extent. If the electrolytes are fully eliminated, the cationic starch can increase the adhesion strength by more than 10% for both fibers.     

乙酰化变性对氧化淀粉与PVA浆液混溶性的影响

以初显分离时间和沉降率为量化指标,定量研究了淀粉氧化后的乙酰化变性对它与１７９９ 、１７８８ 和０５８８ 三种聚乙烯醇混溶性的影响。实验结果表明,淀粉的氧化程度和乙酰化变性、ＰＶＡ分子结构以及混合浆组分都会对其混溶性产生一定的影响。淀粉乙酰化变性和ＰＶＡ 分子结构对淀粉与ＰＶＡ 混溶性的影响是有限的,远不如氧化深度的影响程度大。此外,本文也为进一步提高浆纱质量、降低浆料成本提供了一定的参考依据。     

在经纱上浆中如何实现浆液组分的等效替换

本文通过对各种变性淀粉、PAM、PVA及其混合浆对棉和涤棉的粘附性能及浆膜的机械性能测试分析，证实浆液组分变换的有效性可以通过检验对纤维的粘附力和浆膜的机械性能来判断，指出在浆纱工艺配方中能否少用或不用PVA的关键在于替代材料与淀粉混合后粘附力、浆膜的弹性和断裂功能否保持一致。     

多梳经编机复合针运动机构的设计

分析了多梳经编机复合针的运动组成,将工艺上对梳栉的摆动要求叠加到复合针原有的运动要求上,构成了多梳经编机复合针的运动——摆动、槽针上下运动和针芯与槽针之间的相对运动;研究了一般多梳经编机复合针运动机构的结构和机构的设计方法;通过具体实例说明了设计过程。     

片梭织机制织粗厚斜纹织物产生经缩和吊经的分析

简要分析了片梭织机制织粗厚斜纹织物产生经缩疵点的原因，对如何减少经缩提出了几点建议。     

双主剂型改性丙烯酸酯结构胶挥发过程的质量变化研究

在定温、定压和定湿度条件下,用电子天平对双主剂型改性丙烯酸酯结构胶（AB胶）挥发过程中质量随时间的变化进行了测量研究．实验结果分析表明,AB胶的A和B组分的挥发都包含一快一慢两个过程,对应于两个挥发过程,至少有两种易挥发的单质,而且A组分中它们的含量分别大于18．4％和28．9％,B组分中它们的含量分别大于13．6％和34．7％．AB混合物的挥发只有一个过程,仅存在一种主要易挥发物,其含量至少大于16．1％．根据丙烯酸酯胶固化反应机理,可以认为在A、B组分中存在的易挥发物质分别为甲基丙烯酸和甲基丙烯酸甲酯,而AB混合物的质量变化主要由甲基丙烯酸的挥发所致．     

滚筒送经机构中的摩擦理论分析

讨论了经纱上机张力较大和较小时经纱与送经滚筒表面不发生滑移的条件。在机械结构设计中要综合考虑压力、包围角和滚筒半径对防止纱线滑移的贡献。当压力、包围角和滚筒半径在某一范围内变化时，以临界曲面的方法寻找曲面上与坐标原点距离最小的点，以此点作为理论上的防滑移设计最优方案。     

可替代PVA的丙烯酸类浆料的研制

通过选择合适单体和配比,运用乳液聚合方法合成的丙烯酸类浆料,在PH值7.5、总含固率25％时,为透明冻胶状产品。在上浆浓度范围内,该浆料浆液粘度大小适宜,经粘附力和对涤棉纱上浆后浆纱性能测定,该浆料在粘附、耐磨、强伸、吸湿诸项性能上都优于PVA,可取代PVA用于涤棉上浆。     

Study On the Method for Evaluating the Compatibility of Poly vinyl Alcohol - starch Pastes

A revising method for evaluating the separation behavior of polyvinyl alcohol - starch pastes used as warp sizes had been studied and developed. Cosolvent method involves two important indexes for appraising the separation behavior: (l) initial demising time, and (2) subsidence ratio. However, they sometimes gave confused results because of the different measuring conditions. For obtaining the indexes accurately, the measuring parameters such as paste concentration, component content, and subsidence period of time were carefully studied and proposed. Besides accuracy, the proposed condition could give larger measuring scope and higher sensitiveness than the old one. Moreover, the influences of the paste concentration, component content, and molecular structure of polyvinyl alcohol upon the separation were also investigated. The experiments indicated that the paste concentration and starch content had much effect on the phase separation, whereas the influence of the molecular structure of polyvinyl alcoho     

Effect of Run - in Ratios on the Mechanical Properties of Two - Guide Bars Warp - Knitted Fabrics

Warp knitting technology gets rapid development at present and becomes one of the most important parts of the textiles.But it is less known how the parameters of warp knitting technology affect the mechanical properties of warp-knitted fabrics.This paper presents discuss a research on the relationships between run-in ratio and mechanical properties of the two-bar warp-knittedfabrics through the measurement and analysis of the mechanical properties of various samples with different run-in ratios.The optimal run一in ratios for the reasonable mechanical properties are obtained from above dis-