Tensile,Thermal, and Electrical Conductivity Properties of Carbon Fiber Reinforced Composites Using Itaconic Acid Based Dispersants

We prepared itaconic acid based dispersants (IBDs) by the copolymerization of itaconic acid with acrylic acid, acrylamide, or vinyl sulfonic acid, and compared the efficacy of the IBDs on carbon fiber (CF) dispersion in a water-based system, against that of sodium dodecyl sulphate (SDS) which is widely used as a dispersing agent. The procedure to fabricate nonwoven CF (NCF)/PP composites using IBDs includes the following steps: the synthesis of IBDs, the dispersion of CFs in water by the IBDs, the formation of a NCF, and hot pressing of NCF with polypropylene (PP) layer. We determined the tensile, thermal properties, and the electrical conductivity of non-woven CF/PP composites. It was found that using IBDs as a CF dispersing agent led to the CF/PP composites having better tensile, thermal, and electrical properties, as compared to when SDS was used as a dispersing agent.     

播期对不同筋力型小麦品种淀粉糊化特性的影响

为了研究播期对小麦淀粉品质的影响,2006-2007年度以4个不同筋力型小麦品种(强筋小麦品种豫麦34、中筋品种兰考矮早八和豫麦49、弱筋品种豫麦50)为试验材料,采用分期播种的方式研究了不同播期对小麦淀粉糊化特性的影响.结果表明,基因型和播期对小麦淀粉糊化参数均有一定的影响.不同品种比较,弱筋品种豫麦50的主要黏度参数如峰值黏度、低谷黏度和最终黏度显著小于中筋品种和强筋品种;中筋品种兰考矮早八的糊化温度、峰值黏度、低谷黏度及最终黏度与豫麦34和豫麦49的差异亦达到显著水平.从播期影响看,兰考矮早八、豫麦34和豫麦50的峰值黏度、低谷黏度和最终黏度均以晚播(11月5日)处理的最低,与其他播期间差异达5%显著水平,表明在河南生态条件下晚播(11月份播种)导致淀粉品质变差,但品种之间表现有一定的差异.除豫麦49外,各品种处理间主要黏度参数间的差异与灌浆期间气象条件有关,较高日均温对小麦淀粉黏度影响较大.     

甘蔗渣制备可生物降解复合材料结构与性能的研究

以甘蔗渣纤维为原料,通过对甘蔗渣进行改性,制备新型全纤维素基生物塑料材料,为其高值化利用提供了新的思路。将甘蔗渣进行热水预处理和酸碱预处理,得到BF1和BF2,再将BF1和BF2与聚ε己内酯按一定比例混合制备甘蔗渣复合材料,得到复合材料1和2,通过拉力试验机、X射线衍射(XRD)、扫描电镜(SEM)、热重分析(TGA)等手段研究复合材料的结构与性能的关系。结果表明:复合材料1的拉伸强度、拉断伸长率和撕裂强度均随着BF1含量的增加而降低,而复合材料2随着BF2含量的增加呈先升后降的趋势。BF2含量为20%的复合材料拉伸强度达9.48 MPa时,比BF1复合材料的提高了55%;BF2含量为10%的复合材料撕裂强度达40.32 KN/m时,比BF1复合材料的提高了63%。XRD分析结果发现,复合材料在6.0°、21.5°和23.8°附近有3个明显的衍射峰,说明甘蔗渣含量对复合材料衍射峰的位置和强度影响不大,但BF1复合材料的结晶度明显比BF2复合材料的小。SEM分析结果表明,当复合材料中甘蔗渣含量较少时,甘蔗渣纤维与材料基体有一定的相容性,材料基体对甘蔗渣纤维包裹性好;随着甘蔗渣含量的增加,两相间的相容性逐渐变差,当甘蔗渣含量增加至20%时,材料基体不能对甘蔗渣纤维形成很好的包裹。热重分析结果表明,复合材料1的热稳定性随着甘蔗渣含量的增加而增大,复合材料2的热稳定性呈先增后减的趋势。采用不同方法对甘蔗渣进行预处理,其热塑性能发生不同程度改变,制备的甘蔗渣复合材料的力学性能及微观结构都有所差异,酸碱预处理后的甘蔗渣呈现疏松网络结构,与复合材料中其他组分有更好的相容性,制备出的复合材料力学性能表现更佳。     

物理改性处理对菠萝皮渣膳食纤维物化特性的影响

以菠萝皮渣为原料制备膳食纤维,考察超微粉碎、蒸汽爆破和挤压膨化3种物理改性方式对菠萝皮渣膳食纤维的基本成分、理化性质、形貌结构及生物活性物质溶出量的影响。结果表明:3种物理改性方式均能提高样品阳离子交换能力,增加多酚、黄酮物质的溶出量。其中蒸汽爆破处理能显著提高可溶性膳食纤维含量,在持水持油性方面表现良好。形貌结构分析结果显示,改性后的膳食纤维结构均发生不同程度的变化,但其主要成分及化学结构未受影响。综上所述,蒸汽爆破处理有助于改善菠萝皮渣膳食纤维的品质。     

Effect of Boiling in Water of Barley and Buckwheat Groats on the Antioxidant Properties and Dietary Fiber Composition

In recent years, there has been an ever-increasing interest in the research of polyphenols obtained from dietary sources, and their antioxidative properties. The purpose of this study was to determine the effect of boiling buckwheat and barley groats on the antioxidant properties and dietary fiber composition. Antioxidative properties were investigated using methyl linoleate model system, by assessing the DPPH (2,2-diphenyl-1-picrylhydrazyl) radical scavenging activity and metal chelating activity. The results were compared with butylated hydroxytoluene (BHT). Raw barley and buckwheat groats extracts showed higher DPPH scavenging ability compared to boiled barley and buckwheat groats extracts. Raw barley groats extract exhibited higher antioxidant activity than boiled groats extract in the methyl linoleate emulsion. Higher chelating ability in relation to Fe (II) ions was observed for boiled groats extracts as compared to raw groats extracts. BHT showed small antiradical activity and metal chelating activity, while showing higher antioxidative activity in emulsion system. The analysis of groats extracts using HPLC method showed the presence of rutin, catechin, quercetin, gallic, p-hydroxybenzoic, p-coumaric, o-coumaric, vanillic, sinapic, and ferulic acids. Differences in the content of dietary fiber and its fractions were observed in the examined products. The highest total dietary fiber content was detected in boiled buckwheat groats, while the lowest - in boiled barley groats. The scientific achievements of this research could help consumers to choose those cereal products available on the market, such as barley and buckwheat groats, which are a rich source of antioxidative compounds and dietary fiber.     

红麻韧皮部束纤维抗拉强度的分布规律研究

为探讨红麻韧皮部束纤维抗拉强度的分布规律,将红麻大小植株不同高度、不同层次的韧皮部束纤维进行分离并测定抗拉强度。结果表明,红麻韧皮部束纤维抗拉强度随着植株大小、植株高度及束纤维不同层次的变化在横向和纵向分布上呈现一定的变化规律,推测与红麻纤维发育期间的外界环境条件有密切关系。     

红麻韧皮部束纤维抗拉强度的分布规律研究

为探讨红麻韧皮部束纤维抗拉强度的分布规律,将红麻大小植株不同高度、不同层次的韧皮部束纤维进行分离并测定抗拉强度.结果表明,红麻韧皮部束纤维抗拉强度随着植株大小、植株高度及束纤维不同层次的变化在横向和纵向分布上呈现一定的变化规律,推测与红麻纤维发育期间的外界环境条件有密切关系.     

苎麻单纤维断裂强力统计特征研究

为了研究苎麻单纤维断裂强力的全貌与分布规律,通过采用等速伸长法测得其断裂强力,根据断裂强力的频数直方图的分布趋势,用正态分布的偏度、峰度等参数对其进行分析,用Q-Q图与Kolmogorov-Smirnov（以下简称K-S）检验法检验苎麻单纤维强力的正态性,总体上服从正态分布规律,但有一定偏差,不对称,为右偏尖峰态。同时提出了建立在统计基础上的苎麻单纤维断裂强力指标体系,即运用主体断裂强力、品质断裂强力、平均断裂强力、弱强纤维断裂强力和超强纤维强断裂力五个指标来表征单纤维断裂强力。     

棉纤维微观结构及其性能概述

棉纤维的微观结构决定其具有较高的强度、还原性、耐碱不耐酸性、吸湿膨化及天然转曲等特性。综述了棉纤维微观结构、性能、特点及改良途径,以利于棉花品种的改良、栽培、种植、检验及科学合理使用。     

桑皮纤维的结构与性能

对桑皮纤维的资源、桑皮纤维的化学组成、物理机械性能、形态结构、制备工艺以及产品开发进行了综述,认为桑皮纤维具有较大的使用潜力和广阔的开发前景.     

A Statistical Framework for Selecting Natural Fibre Reinforced Polymer Composites Based on Regression Model

Material selection is an important stage in the development of products from composites process of automotive component application. Numerious different Multi-Criteria Decision-Making tools have their own strenghts and limitations. This paper presents a framework for material selection of natural fibre reinforced polymer composites by using statistical approach. The framework is developed using statistical methods which are simple, multiple and stepwise regression for the material selection process. The performance of potential material is investigated by a statistical analysis such as coefficient of correlation, coefficient of determination and analysis of variance. A case study to select the best composite of parking brake lever is applied to this framework. End results revealed that kenaf reinforced polypropylene is the best candidate for construction of automotive parking brake lever component. The best possible of statistical model for material selection of the composite can be referred by design engineer in composite industry for a multiple application. Moreover, the proposed framework is an aid to help engineers and designers to choose most suitable material.     

竹纤维性能及发展展望

竹纤维是现今市场上极具经济开发价值的新型纺织原料,分为天然竹纤维和再生竹纤维。本文对这两类竹纤维从结构特点、生产流程、性能差异等角度进行了论述,指出了目前市场存在的问题以及未来的发展方向。     

竹纤维性能及发展展望

竹纤维是现今市场上极具经济开发价值的新型纺织原料.分为天然竹纤维和再生竹纤维.本文对这两类竹纤维从结构特点、生产流程、性能差异等角度进行了论述,指出了目前市场存在的问题以及未来的发展方向.     

茶树嫩梢力学特性与粗纤维试验

以黄旦、福鼎大白茶、肉桂、毛蟹、铁观音鲜叶为原料,对其驻芽一、二、三叶进行力学特性及粗纤维含量的测定,研究表明,茶树嫩梢的弹性模量在4 158.88～14 849.11 kPa,最大应力在870.00～1 842.97 kPa,断裂应力在673.33～1 639.62 kPa,叶位对弹性模量、最大应力与断裂应力的影响达到极显著水平,大小排序为:三叶＞二叶＞一叶.茶树嫩梢最大力点应变在10.61％～18.36％,断裂应变在12.19％～26.95％,叶位对最大应力与断裂应力的影响达到极显著水平,大小排序为:三叶＞二叶＞一叶,不同品种有所差异.茶树嫩梢力学参数为茶叶加工机械设计提供了一定的参考价值.     

Application of Polymer Science to Properties of Gluten

Much of the knowledge from polymer science studies can be usefully applied to increase understanding of the properties of gluten and how they are related to composition. Low solubility of gluten proteins compared to many other proteins that have been studied evidently arises from the low entropy of mixing of the largest-sized glutenins and a relatively high value for the Flory-Huggins interaction parameter mainly due to a low concentration of ionisable groups. Grain hardness is a property that appears to depend on the proteins that are concentrated at the starch/matrix interface and how they control adhesion. Dough mixing properties, dough strength and extensibility can be understood in terms of the extension of large glutenin molecules giving rise to rubber elasticity and to the presence of molecular entanglements which contribute strength and extensibility to dough systems.     

红麻韧皮部束纤维抗拉强度测定的样品准备方法研究

通过5种处理方法分离红麻韧皮部束纤维层，测定各层束纤维的直径d及其所能承受的最大拉力Fmax，计算束纤维的极限抗拉强度σ。结果表明，采用亚氯酸钠-冰醋酸和草酸铵方法，不仅能够有效地分离红麻韧皮部束纤维层，而且对束纤维的强度影响较小，可以作为红麻韧皮部束纤维抗拉强度测定的样品准备方法，对准确测定和研究红麻束纤维抗拉强度及其分布具有重要意义。     

红麻韧皮部束纤维抗拉强度测定的样品准备方法研究

通过5种处理方法分离红麻韧皮部束纤维层,测定各层束纤维的直径d及其所能承受的最大拉力 Fmax,计算束纤维的极限抗拉强度σ.结果表明,采用亚氯酸钠-冰醋酸和草酸铵方法,不仅能够有效地分离红麻韧皮部束纤维层,而且对束纤维的强度影响较小,可以作为红麻韧皮部束纤维抗拉强度测定的样品准备方法,对准确测定和研究红麻束纤维抗拉强度及其分布具有重要意义.     

Effect of Chemical Modifications on Surface Morphological,Structural, Mechanical,and Thermal Properties of Sponge-gourd Natural Fiber

Sponge-gourd (SG) natural fibers obtained from Luffa cylindrica plant were chemically treated separately using alkali (5, 10, and 15 wt%), acetic anhydride (5, 10, and 15 wt%), and benzoyl chloride (5, 10, and 15 wt%). Both untreated and chemically treated SG fibers (SGFs) were subsequently characterized using a field emission scanning electron microscope, a Fourier transform infrared spectrometer, an X-ray diffractometer, a universal testing machine, and a thermogravimetric analyzer. Surface analysis by scanning electron microscopy shows that the alkali treatments promote better outer surface layer than other treatments of the SGF with the exposition of inner fibrillar structure, thereby increasing roughness of the fiber surface. Alkali treatment also improves the crystallinity and exhibits new chemical bond formation in the SGF. The tensile strength and Young’s modulus have been analyzed through a two-parameter Weibull distribution model, where a significant increase in mechanical property of benzoylated fibers has been observed. The thermal stability of the modified fibers is also found to increase by acetic anhydride treatment.     

砂引发对谷子种子活力的影响

试验选用长生04、长农35、长农36、长农38、长农39和晋谷27共6个谷子品种为材料,每品种设置3种处理,研究不同含水量的砂基质引发对谷子活力的影响,结果表明,适宜的砂引发处理能提高谷子种子的活力,6个谷子品种砂引发基质的适宜含水量均为1％。     

砂引发对荞麦种子萌发及活力的影响

试验选用安徽甜荞-1、安徽甜荞-2、青海甜荞、青海苦荞4个荞麦种子样品为材料,每品种设置4种处理,研究不同含水量的砂基质引发对荞麦种子萌发及活力的影响。结果表明,适宜的砂引发处理能不同程度地提高荞麦种子的活力,砂引发基质的适宜含水量安徽甜荞-1、安徽甜荞-2和青海甜荞均为5．7％,青海苦荞为3．8％。