Comparative Effectiveness of Use of Fluorine-Containing Polymer Modifiers to Reduce the Wettability of Viscose Fibres

The comparative effectiveness of using polyfluoroalkyl acrylates, which have the structure of a fluoroalkyl radical, in reducing the wettability of viscose fibres was investigated. It was shown that incorporation of an oxygen atom in the fluoroalkyl chain decreases the efficiency of modification with all other conditions being equal. An important increase in the level of unwettability can be attained by regulating the colloid chemical indexes of polyfluoroalkyl acrylate latexes, their particle charge values in particular.     

Surface Energy and Wettability of Modified Cellulosic Fibres for Use in Composite Materials

The surface modification of cellulosic substrates in the form of powders and sheets was carried out using nonpolar oligomeric and polymeric reagents bearing isocyanate and anhydride reactive moieties. The characterization of these surfaces by inverse gas chromatography and by dynamic and equilibrium contact angle measurements, before and after the treatments, revealed that the lower the polarity of the coupling agent, the higher the loss of hydrophilic character of the substrate. In particular, the use of styrenic copolymers of rather high molecular weight gave rise to essentially dispersive-modified surfaces which should be highly suited for the preparation of composites based on nonpolar macromolecular matrices.     

Surface Energy and Wettability of Modified Cellulosic Fibres for Use in Composite Materials

The surface modification of cellulosic substrates in the form of powders and sheets was carried out using nonpolar oligomeric and polymeric reagents bearing isocyanate and anhydride reactive moieties. The characterization of these surfaces by inverse gas chromatography and by dynamic and equilibrium contact angle measurements, before and after the treatments, revealed that the lower the polarity of the coupling agent, the higher the loss of hydrophilic character of the substrate. In particular, the use of styrenic copolymers of rather high molecular weight gave rise to essentially dispersive-modified surfaces which should be highly suited for the preparation of composites based on nonpolar macromolecular matrices.     

Wettability of Surface Oxyfluorinated Polypropylene Fibres and Its Effect on Interfacial Bonding with Cementitious Matrix

The surface of high molecular weight polypropylene monofilament fibre was modified using a oxyfluorination method. The oxyfluorination treatment level was varied and a hydrolysis post-treatment was also applied. Contact angles of oxyfluorinated, hydro-lyzed oxyfluorinated and unmodified polypropylene fibres were obtained by dynamic contact angle (DCA) measurement using three liquids of known dispersion, acid and base surface free energy components. The surface free energies were then calculated according to the acid-base theory developed by Good, van Oss and Chaudhury. Surface oxyfluorination largely increased the acid and base components of the fibres' surface free energy compared with unmodified polypropylene fibres. The oxyfluorinated and unmodified polypropylene fibre surfaces were observed by Scanning Electronic Microscopy and Photoacoustic Infrared Spectroscopy. It was found that the surface oxyfluorination largely increases the roughness of the polypropylene surfaces and the carbonyl group content increases as the treatment level increases. The interfacial shear bond strengths between the cementitious matrix and the polypropylene fibres treated under various conditions were determined by embedded fibre pull-out tests. Results showed that the fibre surface oxyfluorination treatments increase the interfacial bond strengths. The correlations between the shear bond strengths and surface free energy components were established. Results showed that fibre/concrete interfacial bonding was best correlated with the acid component of surface free energy of polypropylene fibres.     

纤维临界表面张力测定技术

用ＷＤＳ－Ｉ型接触角测定仪可测定纤维材料的临界表面张力，用硅烷偶联剂处理玻璃纤维，测定偶联剂处理前后玻璃纤维临界表面张力的变化，可了解偶联剂对玻璃纤维表面浸润性能的影响。因此临界表面张力测定技术是复合材料界面研究的一种重要方法。     

Experimental Investigation of Convective Heat Transfer Between Silicon-Melt and Solidification Front

Convective heat transfer between silicon melt and solidification front during Bridgman-type solidification process in a ceramic crucible has been investigated by means of heat balance analysis of the crucible during the process. The effect of aspect ratio on the Rayleigh and Nusselt numbers has been investigated. For a large crucible size (with inner diameter of about 0.50-m), the dependence correlates well with the empiric formula Nu?=?0.303 Ra^0.279. For a small crucible size (with inner diameter of about 0.20-m), the dependence correlates well with the empiric formula Nu?=?0.181 Ra^0.285. The experimental data obtained were compared with the available literature experimental and numerical simulation data.

     

亲水性聚烯烃纤维的改性方法研究进展

聚烯烃以其优异的性能、低廉的价格和越来越广泛的用途,日益成为一种重要的合成高分子材料的主体。但它极弱的亲水性限制了在一些领域的应用。介绍了近几年国内外通过化学接枝、等离子体接枝、辐射接枝、表面光接枝等方法对聚烯烃表面亲水性改性的研究进展。     

页岩润湿性及影响因素研究

润湿性是影响页岩油气藏中地层流体分布和运移的重要储层性质,在页岩气勘探开发中占有重要地位。由于页岩自身矿物组成、物理性质和孔隙结构的复杂性与非均质性使得页岩油气藏润湿性评价变得困难。从页岩润湿的形成机制、页岩润湿的表征手段以及影响页岩润湿的主要因素三个方面对页岩润湿研究目前取得的部分认识进行了探讨,并提出了相应的意见与期望。     

Solid State NMR Study of Natural Fibres

Abstract

The investigation of natural fibres by nuclear magnetic resonance (NMR) showed that the sugarcane fibres are more rigid than coconut and sisal fibres. This can be explained in terms of the changes in the chemical compositions and in the chains molecular packing of the distinct natural fibres.     

高吸湿涤纶织物的染整工艺研究

针对高吸湿涤纶的特性,选用分子结构简单且对涤纶微结构敏感的低温型分散染料,对其针织物在常温下进行染色。与常用的高温高压工艺相比,该工艺不仅操作简易,染色效果好,而且节能、节水,提高了生产效率,因而具有良好的应用前景。     

Spectral Study of the State of Dyes in Chemical Fibres

The results of the study show that the use of the diffuse reflection spectrum of dyed fibre materials can be used to obtain quantitative information on the electron absorption spectra of dyes in the sorbed state. In analyzing the concentration curve of the absorption spectra of vat dyes on polyester fabric, aggregation of the dyes inside the polymeric material was found. The study of coloration of polyamide fibre revealed the appearance of polar and nonpolar interactions of the sorbed molecules of acid dyes with the polymer substrate.     

炭黑粉末润湿性质的研究

炭黑润湿性能的研究是炭黑性质研究的重要内容,润湿是指液体从固体表面取代气体的过程。润湿过程涉及固体和液体的表面性质,以及固液分子间的相互作用。在研究炭黑的润湿作用时,接触角大小是衡量润湿性优劣的较为方便的方法。通过动态法测定了接枝炭黑和未接枝炭黑在某些溶剂中的接触角,考察了接触角的变化规律。结果表明,炭黑表面接枝水溶性高分子将明显改善其润湿性质。     

The Adhesion of Polymers to Each Other and to Fibres

Autohesion is a diffusion process but adhesion between different polymers is best secured by forming cross-links at the interface. The nature of the polymer surface is but imperfectly understood and its surface free energy can vary with preparation of the sample. The surface may vary from a liquid or pseudo-liquid to one more cross-linked or saturated than the bulk material. The use of solvents in securing adhesion between polymers can adversely affect the bond and solvent from a wiped surface is absorbed and is detectable after 2 weeks. The reactions of elastomers with fibres is discussed and involves both chemical reaction and morphological complexity. RFL treatment gives molecular adsorbed films of resin on latex particles. The RF modification “Pexul” seeks to match properties of resin and fibre whilst maintaining the usual reactivity, surface and chemical of RF resins. Surface halogenation of polymers is shown with model liquids to lead to hydrogen bond formation, thus explaining the improved adhesion of polyurethane. Mechanical interaction of elastomers and textiles is emphasized by reference to new information on penetration of elastomer into the yarn as well as into the weave. The joining of rubber-textile composite sheets is discussed.     

连续莫来石陶瓷纤维的制备研究

采用异丙醇铝和氯化铝作铝源,正硅酸乙酯作硅源,通过溶胶-凝胶法合成含有Al-O-Si长链的溶胶,干法纺丝制备莫来石连续纤维.对溶胶及凝胶进行了FT-IR分析和TG-DTA分析,研究了其光谱和热学性质,并对烧结后的纤维做SEM观察、XRD分析、XRF分析等.测试结果表明,在前驱体溶胶中含有Al-O-Si及Si-O-Si等为骨架的长链,具有较好的可纺性和稳定性;所得纤维直径在十几个微米,晶粒比较细小,在100～200nm之间;烧结过程中没有其它晶相出现.     

纳米CaCO3与矿纤维在PVC中的应用

研究了纳米CaCO3和矿纤维对聚氯乙烯(PVC)复合材料力学性能的影响.结果表明.在硬质PVC复合材料中填充材料的形状对PVC复合材料的力学性能影响较大,纤维状的矿纤维比球状的纳米CaCO3作为填充材料对硬质PVC复合材料的力学性能明显要高;而在软质PVC复合材料中,填充材料的形状对拉伸性能的影响较小.     

改性活性炭纤维脱除COS的研究

本研究采用的催化剂为活性炭纤维,采用了Co~(2+)、Ni~(2+)、Fe~(3+)、Cu~(2+)等多种金属离子通过浸渍法改性活性炭纤维的性能,对COS进行深度脱除。本实验采用固定床反应器,分别通过改性离子的种类、含量、原料气的伴生组分、反应气氛、反应相对湿度和温度的不同催化剂的脱硫性能。结果表明:改性后的催化剂在脱硫性能上有了明显的提高,并根据实验结果推测了过渡金属离子在活性炭纤维上脱除COS的反应机理。     

Padding,Drying, Steaming and Baking Stages in the Application of Dyes to Cellulosic Fibres and their Blends with Polyester Fibres

Padding, drying, steaming and baking are the basic unit processes of continuous dyeing; special aspects of this very wide range of processes have been examined. A new technique of padding has been developed in which the air in the material is removed by applying a high vacuum. The material is then immersed in the treating liquor without release of the vacuum; impregnation occurs on release of the vacuum. This technique can also be used in batchwise dyeing. Its advantages are that penetration is greatly improved and excellent results are obtained on completely unprepared material without the need to use wetting agents; in batchwise dyeing the uniformity of dye absorption during the initial stages of dyeing is improved. In this padding system, the pressure of the atmosphere forces the liquor into every interstice of the material, in contrast to the situation in conventional padding, where the trapped air opposes the pressure of the pad mangle. Results of the application of this technique are illustrated and discussed. Drying, steaming and baking have been considered as heat- and mass-transfer unit operations, and the techniques and data of chemical engineering have been applied to show that this approach can give much useful information to the dyer without the need for difficult empirical experimentation. There are, however, few data derived on a textile basis; even so, the standard data available show reasonable agreement with textile experience. More data in this field are required. Thoughtful use of such studies could lead to improved textile processing machinery. Finally, the ICI high-temperature (HT) steaming process (with superheated steam) and continuous pressure steaming are compared with comparable conventional treatments. The advantages and limitations of these systems are discussed. The two new methods are shown to be complementary, but the HT steaming process is more versatile in application and simpler in design.     

硅酸铝纤维/石英复合隔热材料的研制

本文研制了一种纤维布/纤维毡叠层、层间穿刺纤维加强的纤维增强石英基复合材料,该材料体积密度小、导热率低、可耐受1200℃高温,有希望成为我国航天运载器的新一代复合隔热材料.