几种极性增塑剂对淀粉／PVA混合浆相分离速度的影响

以初显分离时间为量化指标,选取丙三醇、尿素,1,2-丙二醇及乙二醇四种淀粉和PVA的常用增塑剂,定量研究了这些极性化合物对淀粉与PVA-1799及PVA-1788混合浆液相分离速度的影响,结果发现这4种极化化合物都能在一定程度上降低淀粉与PVA-1799混合浆液的相分离速度,尿素还具有提高淀粉与PVA-1788混合浆液稳定性的功能,此外,本还研究了丙三醇和尿素的用量,淀粉与PVA的混合比例对混合浆液相分离速度的影响。     

羟基增塑剂的羟基数目对淀粉浆料增塑作用的影响

以淀粉浆膜的断裂伸长为评价标准,通过对比试验评价羟基增塑剂对淀粉浆料的增塑作用,从分子结构上认识羟基增塑剂的羟基数目对淀粉浆料增塑作用的影响,并通过浆液特性及黏附性能评估羟基增塑剂正戊醇、正丁醇、1,2-丙二醇、乙二醇、甘油、1,1,1-三羟甲基丙烷、季戊四醇、木糖醇及山梨醇的使用效果.研究结果表明:羟基增塑剂对淀粉浆料都具有增塑作用,能够改善淀粉浆膜脆而硬的缺陷.随着增塑剂羟基数目的增加,淀粉浆膜的断裂伸长率逐渐增大;在羟基数目为3时,增塑作用达到最大;但进一步增加羟基数目,增塑作用下降.在所研究的羟基增塑剂中,甘油和1,1,1-三羟甲基丙烷的增塑作用效果最明显,以其作为淀粉浆料的增塑剂,可以减少浆纱和织造落物,提高织造效果.     

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。     

聚己内酯型聚羟基氨基甲酸酯的合成

以聚己内酯二元醇(PCL Diol)、丁二酸酐以及碳酸甘油酯为原料,合成了端基为五元环碳酸酯的聚己内酯功能性大单体(PCL 2GC);以PCL 2GC、己二胺及硅烷偶联剂为原料,研究了反应条件对合成线性聚羟基氨基甲酸酯(PHU)相对分子质量及其分布的影响,以及交联密度和交联方式对PHU/SiO2热力学性能的影响.结果表明：线性PHU的相对分子质量随PCL 2GC浓度和反应温度的升高而先增后减,随反应时间、胺用量的增大而降低;PHU的耐热温度相比于类似结构的传统聚氨酯提高了30~40 ℃,PHU/SiO2交联聚合物的结晶度及热稳定性随交联密度的增大而降低;交联聚合物中无定形SiO2的分布较为均匀.     

增塑剂对大豆分离蛋白/纤维素/淀粉复合膜的性能影响

以大豆分离蛋白(SPI)、羧甲基纤维素(CMC)和豌豆淀粉(PS)为成膜物质,甘油、山梨糖醇、聚乙二醇和吐温为增塑剂,采用流延法制备了三元复合蛋白膜SPI/CMC/PS,研究了几种增塑剂对复合膜性能的影响。采用红外光谱对各种类增塑剂的复合膜进行红外表征。试验结果表明:增塑剂甘油和山梨糖醇对SPI/CMC/PS三元复合蛋白膜的拉伸强度和断裂伸长率的影响较好。红外光谱表明,增塑剂增塑三元复合膜SPI/CMC/PS的结构相溶性好。     

混合条件对阳离子淀粉与聚乙烯醇混溶性的影响

利用初显分离时间和沉降率作为浆液混溶性的评定指标,研究了混合条件对阳离子淀粉与聚乙烯醇混合浆液混溶性的影响,实验结果表明,煮浆温度、浆液质量分数、搅拌时间、搅拌速度以及混合方式都会对阳离子淀粉混合浆液的混溶性产生一定的影响,并且增加煮浆温度、搅拌速度和搅拌时间,降低混合浆液的质量分数,以及采用先调煮再混合的方式调浆,都有利于提高混合浆液的混溶性.     

木薯淀粉生产中浆渣分离的工艺与设备

对木薯淀粉生产中浆渣分离的工艺流程与设备进行了讨论。根据木薯原料的特点提出了新的浆渣分离工艺流程设计方案,新工艺可将淀粉的提取率从71%提高到84%。     

木薯淀粉生产中浆渣分离的工艺与设备

对木薯淀粉生产中浆渣分离的工艺流程与设备进行了讨论。根据木薯原料的特点提出了新的浆渣分离工艺流程设计方案，新工艺可将淀粉的提取率从71％提高到84％。     

磷酸酯淀粉／PVA共混浆膜的织态结构与性能

研究了淀粉磷酸酯化变性和聚乙烯醇(PVA)结构对磷酸酯淀粉(SPH)/PVA共混浆膜织态结构与力学性能的内在联系,探讨了SPH与PVA间的共混比对浆膜结构和力学性能的影响.实验结果表明,磷酸酯化变性深度、PVA分子结构及共混比对共混浆膜的织态结构及力学性能有显著影响.随着淀粉磷酸酯化变性深度的增大,共混浆膜的断裂伸长率增大,断裂强度先增大后减小;当取代度为0.016时,断裂强度达到最大值.随着SPH质量分数的增加,共混浆膜的断裂伸长率减小,断裂强度先减小后增大;当SPH/PVA的共混比为50/50时,断裂强度达到最小值.提高PVA相对分子质量,增大醇解度,都有利于改善共混浆膜的力学强度,提高耐屈曲性能.     

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 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     

Starch-g-poly (vinyl alcohol)as Compatibilizer for Reducing the Phase Separation Rates of Polyvinyl Alcohol/Cornstarch Pastes

Starch-g-poly(vinyl alcohol) as a compatibilizing agent for reducing the phase separation rates of polyvinyl alcohol/starch pastes has been investigated by blending and dissolving the two polymers in distilled water. The separation rates were quantitatively evaluated by the term of initial demisting time. The grafted starches, with a series of grafting ratios, were prepared by grafting a number of vinyl acetate onto granular cornstarch in aqueous dispersion and then alcoholating in methanol. It was found that the addition of small amounts of starch- g-poly ( vinyl alcohol) in the size compositions can effectively decrease the separation rates of the blended pastes in comparison to pure starch/PVA ones. Moreover, the influence of the grafting ratio, starch content, and PVA variety on the separation rates was also studied.     

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…     

正戊醇对形成淀粉微乳液的影响

借助XRD和IR技术及通过对淀粉微乳液相体积和电导值的测定,研究了正戊醇对形成含量不同的淀粉微乳体系产生的影响。结果表明:随着淀粉含量增大,正戊醇的助表面活性剂作用逐渐减弱,加入的正戊醇主要与其中的直链淀粉生成了络合晶体,被表面活性剂分散的淀粉自身充当着助表面活性剂的作用。但正戊醇的加入有利于生成稳定的W/O型淀粉微乳液。     

玉米淀粉和糯玉米淀粉的微波糊化特性研究

以玉米淀粉和糯玉米淀粉为原料,采用微波加热制备玉米淀粉糊,并与水浴加热制备的淀粉糊相比较,以碘兰值和酶解力为指标,研究了微波法对淀粉糊化特性的影响.研究结果表明,糊化过程中水浴法和微波法糊化淀粉的碘兰值和酶解力均随糊化时间的延长逐渐上升,其中微波糊化淀粉的速度比水浴快,但微波加热玉米淀粉糊的碘兰值和酶解力比水浴加热低.     

氯化锂对静电纺PVA纳米纤维的拉伸过程的影响

在静电纺丝过程中,如果纺丝液完全绝缘或者使用的电压不够高,静电力就不能克服表面张力,这时无法纺制纤维.在纺丝液中加入适量的盐,可以增加射流的表面电荷,射流在电场中的受力发生改变,使得纤维容易纺出.在聚乙烯醇(PVA)中添加不同质量分数的无机盐氯化锂后,对静电纺丝过程中的纤维形态产生影响.实验结果表明氯化锂显著降低了PVA溶液的表面张力,纺丝过程变得容易,纤维拉伸更显著.实验结果与理论研究的结果十分吻合.     

驼绒/水溶性维纶包芯纱的包覆效果及性能

采用改进的环锭纺细纱小样机,试纺了9种不同规格参数的驼绒/水溶性维纶包芯纱,考察芯纱张力、芯纱含量和捻度等因素对包覆效果的影响,并测试包芯纱的拉伸性能、条干均匀度和毛羽指数等指标,获得了最佳纺纱工艺参数.研究结果表明:适中的芯纱张力可以提高包芯纱的包覆效果;芯纱含量越小,纱线包覆效果越好,断裂强力越高;捻度越大,包覆效果越好,毛羽指数越小,但断裂强力先增加后降低.优选工艺参数:芯纱含量为19.1%~19.9%;捻度为300~325捻/m;在芯纱不断裂的情况下,提高芯纱张力有利于改善包覆效果.     

用TGA测定PVA灰分的方法

结合热重分析仪的结构特点,研究了热重分析仪测定聚乙烯醇灰分的方法。研究表明:热重分析具有仪器性能稳定、自动化程度高的优点,显著缩短了分析时间,将测定时间由约8 h缩短为约30 min,提高了分析效率和工作效率。     

PVA分子结构对纯纺POPAN短纤经纱上浆性能的影响

为解决纯纺聚丙烯腈预氧化纤维(POPAN)短纤单纱强力低、耐磨性差、毛羽较多、织造困难等问题,采用聚乙烯醇(PVA)对纯纺POPAN短纤经纱进行上浆处理,以提高其可织性.研究了PVA聚合度和醇解度对浆液粘度、粘附力、浆膜水溶性及回潮率的影响,探索了PVA浆液与纯POPAN织物的静态接触角之间的对应关系,为用于纯纺POPAN短纤经纱上浆的PVA选择奠定基础.然后以PVA浓度及上浆率为变量,通过浆纱的增强率、减伸率、耐磨性、毛羽降低率及退浆性的测试,最终确定适合的上浆浓度.结果表明:PVA-1788在对POPAN纤维的粘附力、浆膜性能及可退浆性方面较理想;浆液中PVA-1788浓度为7%时,纯纺POPAN短纤浆纱的各项物理性能较好.