超声波处理对棉纤维力学性能影响研究

本文利用超声波对处在蒸馏水的棉纤维进行处理,观察、测试计算棉纤维的微观形貌与聚合度、分子量与断裂强力。研究表明,棉纤维经过在蒸馏水静止侵泡、在蒸馏水中经超声波处理后,其天然转曲的扭曲率均呈现下降趋势,而纤维直径、反光强度增加。两种实验方式的棉纤维在0.5小时处,断裂强力都略有上升,其后在蒸馏水静止侵泡处理的棉纤维,其聚合度、分子量与断裂强力变化不大,而经超声波处理后的棉纤维均有较大幅度的降低。     

超声波处理对对位芳纶纤维侵蚀性能的影响

 本文以国产芳纶1414纤维和美国杜邦Kevlar49纤维为实验材料,通过红外光谱和粘度的检测并计算其聚合度,比较分子结构的差异。同时通过超声波对蒸馏水中和自配海水中的芳纶纤维进行处理,经扫描电镜（SEM）和力学性能测试,发现经过超声波处理后的纤维表明,纤维表面出现了裂缝,呈分丝帚化及细纤维化现象,存在着微细原纤维,强力弱环增加,纤维断裂强度与断裂伸长率均下降,本文利用分子运动理论对纤维的力学损失进行分析。     

聚酰胺纤维芳纶1414包覆纱的拉伸性能探讨

探讨聚酰胺纤维芳纶1414包覆纱的制备方法及拉伸断裂强力性能。以聚酰胺纤维为外包纱、芳纶1414为芯纱制备聚酰胺纤维芳纶1414双向包覆纱,测试聚酰胺纤维芳纶1414包覆纱的拉伸断裂强力,研究导纱钩与空心锭距离、捻度对包覆纱拉伸断裂强力的影响规律。结果表明:导纱钩与空心锭距离在7.5 cm～15.5 cm范围内,聚酰胺纤维芳纶1414包覆纱的断裂强力呈现先增加后减小的规律,且导纱钩与空心锭距离为10.5 cm时包覆纱断裂强力最大;随着包覆纱捻度的增加,聚酰胺纤维芳纶1414包覆纱的断裂强力呈现先增加后减小的规律,且捻度为(400/320)捻/m时包覆纱断裂强力最大。认为:合理的工艺设计可有效提高包覆纱拉伸断裂强力。     

芳纶1313棉混纺纱及其织物的力学性能研究

探讨不同混纺比对芳纶1313棉混纺纱及其织物力学性能的影响规律。通过测试不同混纺比芳纶1313棉混纺纱的断裂强力、断裂强度、断裂伸长率及其织物的断裂强力、撕裂强力,研究了不同混纺比与纱线及其织物力学性能的关系。结果表明:随着芳纶1313纤维含量的增大,芳纶1313棉混纺纱的断裂强力先减小后增大;芳纶1313棉混纺织物的断裂强力、撕裂强力也增大,且同一混纺比时,织物的经向断裂强力和经向撕裂强力均大于纬向断裂强力和纬向撕裂强力。     

海水环境对国产芳纶1313性能的影响

利用海水对国产芳纶1313进行处理,测试海水浸泡前后芳纶1313的质量、线密度、断裂强力、断裂伸长率等指标的变化情况;采用扫描电子显微镜,观察海水处理前后纤维表面和断面形貌。结果表明:芳纶1313经海水的长期浸泡后会受到侵蚀,使芳纶1313的质量、线密度、强力等下降,从而影响芳纶1313制品的耐用性。     

Study on PPTA Microthermodynamic Property

研究某一国产对位芳纶和Kevlar49纤维热力学性能.通过电镜对两种纤维的形貌进行了观察,并由红外光谱和黏度检测计算其聚合度,比较分子结构的差异,同时测试对比了两种对位芳纶纤维热力学性能.研究表明:两种纤维横截面均为几何圆形,化学结构成分也相同.国产对位芳纶纤维的分子量和聚合度均低于Kevlar49纤维.热力学性能试验表明:Kevlar49纤维具有更好的力学性能.认为:要提高国产对位芳纶纤维的力学性能必须提高其聚合度.     

纳米SiO_2改性环氧树脂对高性能纤维力学性能的影响

对用纳米SiO2改性环氧树脂提高高性能纤维的性能进行了实验,分析了其对高性能纤维力学性能的影响。结果表明,经环氧树脂改性处理后的高性能纤维断裂强力均高于原纤维断裂强力,纳米SiO2微粒加入到环氧树脂中能提高复合后纤维的断裂强力;碳纤维和超高子量聚乙烯纤维的断裂强力最大时对应的纳米SiO2浓度为3%,而芳纶纤维断裂强力值最大时对应的纳米SiO2浓度为5%。     

纳米光触媒对棉织物理化性能的影响

将不同浓度的纳米TiO2光触媒剂采用浸轧工艺处理到棉织物上,分别用紫外线和自然光作为光源照射织物,通过测定纤维的聚合度、结晶度,以及织物的断裂强力、撕破强力、K/S值变化等,研究了纳米光触媒剂对纤维理化性能和织物颜色的影响.试验发现,经纳米TiO2处理后棉纤维的聚合度、断裂强力和撕破强力均有不同程度的下降,但结晶度和晶态结构没有显著变化.     

苎麻生长期与其纤维纺织性能的关系研究

研究了三季苎麻纤维细变、单纤强力、结晶度和聚合度随苎麻生长期延长而逐渐变化的情况.实验表明:随着苎麻生长期的延长,特别是到了生长后期,单纤维变得成熟粗壮,纤维聚合度、结晶度、强力升高较快,而纤维细度变粗较快.     

芳纶纤维的热降解过程分析

芳纶纤维是高性能纤维,在高温条件下使用会老化。必须通过有效的表征和研究,了解和评估芳纶纤维在热环境下的热降解过程。用TGA-DTA/FT-IR对两种芳纶纤维(Kevlar 49、Nomex)的热降解过程进行了研究。实验结果表明,两种芳纶纤维有类似的热稳定性,但它们的热降解过程和温度是不同的。Kevlar 49纤维对位芳纶共聚物降解温度较高,在空气中其初始分解温度为548.1℃。Nomex纤维在空气中具有较低的热降解温度,其初始分解温度为423.7℃。温度升高到800℃时,这两种纤维都被完全分解。在加热过程中,可以得到TGA-DTA/FT-IR测试的波数、吸收时间和三维图像。根据TG曲线,可以分析分解产物的红外光谱,全面研究芳纶的热分解过程。     

新合成纤维与分散染料染色(一)

新型合成纤维如PTT、PLA纤维和芳纶、芳砜纶高性能纤维等产量近年来逐步上升.这些新纤维均采用分散染料染色,不同之处在于PTT纤维可应用PET纤维的传统分散染料;芳纶则需施用特殊添加剂存在下的载体染色,要求载体无毒、无味、易洗除,给色量好,不影响牢度;PLA是脂肪类聚酯,由于分子结构相差大,因此介电常数、极性及与染料的作用力也有差异,造成匀染性、色相、牢度存在差异.本文介绍采用溶解度参数或无机性值/有机性值,从传统分散染料筛选或设计PLA专用分散染料的分子结构.     

超高分子量聚乙烯纤维在防弹和防刺材料方面的应用

介绍了超高分子量聚乙烯纤维的力学性能及其在防弹和防刺材料方面的应用,包括超高分子量聚乙烯纤维制造防弹和防刺材料的结构形式、不同结构形式对防弹和防刺性能的影响,以及目前超高分子量聚乙烯纤维防弹和防刺材料性能的测试方法。     

精梳有机棉/汉麻/Modal混纺纱的开发

介绍了汉麻纤维的物理指标和性能特点。根据有机棉、汉麻纤维和Modal纤维的性能差异,采用原料混和预处理、一次成卷成条的方法进行开发。生产的混纺纱导湿快干、柔软时尚、健康环保,不仅具有抗霉抑菌、防紫外线、消散音波的特点,还具有耐热耐腐蚀、抗静电的特性和良好的抗电击穿能力。     

常压氩等离子体改善超高分子量聚乙烯纤维的界面性能

 改变低温常压氩等离子体处理条件,考察处理后超高分子量聚乙烯纤维束强度与环氧树脂层间剪切应力与各变化因子的关系曲线,通过比较性能的变化,研究氩等离子体处理条件对纤维界面性能的影响。观察处理后纤维束纵向的微观结构,测试用最优化工艺参数处理的纤维束制成的纤维增强复合材料的单向性能,进一步论述等离子体处理对纤维束黏合性能的影响。     

物理改性腈纶抗起毛起球性能研究

分析了织物起毛起球的机理,结合腈纶的起毛起球特点,通过改变纺丝工艺,使腈纶的物理性能发生一定变化,从而开发出了一种新的抗起毛起球腈纶。通过测试比较了物理改性腈纶与常规腈纶的性能差别,得出物理改性腈纶织物的抗起毛起球性能有了很大的提高。     

Sunflower Hull Flour as a Potential Dietary Fiber Supplement

Confectionery hull flour (CHF) and oilseed hull flour (OHF) were evaluated as potential dietary fiber supplements. Analyses included: proximate analyses, neutral detergent fiber, acid detergent fiber, acid detergent ligrdn and buffered acid detergent fiber, water- and oil-holding capacity, pH, cation exchange capacity, emulsifying activity (EA), Gardner color values, and sensory evaluation. CHF (90.7% NDF) was slightly higher in dietary fiber than OHF (83.4%). Sunflower hull flours had a relatively high cation exchange capacity, equivalent to lettuce. Sunflower hull flours were highly variable in color and EA. There was no significant difference in aroma of muffins made with hull flour or wheat bran but differences did exist in appearance, flavor and texture. Sunflower hull flour showed potential as a dietary fiber supplement but its exact physiological effects have not yet been established.     

Fiber sources for complete calf starter rations

Complete calf starter rations containing either 1) alfalfa hay, 2) cottonseed hulls, or 3) alfalfa-beet pulp as sources of fiber were fed to Holstein heifer calves at two locations on a limited milk program from 3 days to 12 wk of age. Rations were isonitrogenous and similar in content of crude fiber and acid detergent fiber. Although growth and development were normal on all rations, calves fed the cottonseed hull ration consumed more starter and gained more body weight than calves fed the other sources of fiber. The similarity of feed efficiencies, rumen pH, and molar ratios of volatile fatty acids between rations indicated no appreciable differences in rumen development or function. The growth response of calves fed the cottonseed hull ration appeared to be a result of better ration acceptability for which no reason was evident. Calves raised at Puyallup gained more body weight than calves at Pullman, and these gains were made more efficiently. These location effects may be related to seasonal differences and greater demands for production of body heat. Although the incidence of scours was less for calves fed alfalfa hay starter, the incidence and severity of bloat were higher for that ration.     

世纪之交的我国化纤工业

回顾了中国化纤工业的发展历程及纺织工业在国民经济中的重要作用。化纤和纺织工业的发展坚持了改革开放 ,经济发展、人口增长和外贸扩大是化纤工业发展的基础 ,化纤在纺织原料中的需求越来越大。指出中国加入WTO后将更加对外开放 ,世纪之交的我国化纤工业成就重大 ,前景光明。     

Comparative analysis of total proteins, amino acids, carbohydrates, fibers, lipids, macro and micro minerals contents in different types of Egyptian bread

Seven types of Egyptian bread were collected from different rural and urban areas. The chemical composition including total proteins, amino acids, carbohydrates, fibers, lipids, macro and micro minerals contents were determined. Total proteins content was higher in shamssy bread than other types of bread. Crude fat has the highest value in bread made from mixture of cereals, especially when trigonella is found, while fiber content was highest when mixture of cereals containing sorghum is used. Ash content of bread made from maize + wheat showed a higher value than other types and the differences were highly significant. Ca, Mg, Cu, and Fe were higher in bread made from sorghum + trigonella blend than other types of bread. Variations in the amino acids content of the different types of bread were found; these differences due to the origin of different cereals, the method of bread processing and the differences in the extraction rates of the flour.     

Molecular weight of guar gum affects short-chain fatty acid profile in model intestinal fermentation

Dietary fiber exerts many beneficial physiological effects; however, not all types of dietary fiber display the same effects. Partially hydrolyzed guar gum (PHGG), a lower molecular weight form of guar gum, is more easily incorporated into food, but may have less pronounced physiological effects than the native form. The aim of this study was to identify differences in intestinal fermentability based on the molecular weight of guar gum. Guar gum of four molecular masses (15, 20, 400, and 1,100 kDa) was fermented using a batch in vitro fermentation system. Human fecal inoculum was the source of microbes. The 400-kDa fraction produced the greatest concentrations of total short-chain fatty acid (SCFA) at 8 h and the highest amounts of butyrate at 24 h. At 24 h, the 400-kDa fraction produced more total SCFA and propionate than the 15 kDa, but was not different than 20 kDa or 1,100 kDa fractions. The molecular weight of guar gum was positively correlated with acetate production and negatively correlated with propionate production. This study concludes that 400-kDa guar gum may be optimal for intestinal fermentability. In conclusion, the molecular weight of guar gum affects in vitro fermentability and should be considered when adding to a food or beverage.