Fibres adhesive properties

A fabric made by uniting a mass of staple fibres into a continuous sheet by using the adhesive properties of a bonding agent, usually rubber latex, either natural or synthetic. In textile technology the term is applied to fabrics which are not woven, such as felted fabrics. Non-woven fabrics are now being termed bonded fabrics. 

This is undoubtedly one of the most promising medical applications for chitin and chitosan. The adhesive properties of chitosan, together with its antifungal and hactericidal charactCT, and its pameahOity to oxygen, are very important properties associated with the treatment of wounds and burns. Diffa-ent draivatives of chitin and chitosan have been patented for this purpose in the form of membranes, woven fibres, hydrogels, etc. Some of these formulations have been released on the market, like Beschitin in Japan (based on chitin) or HemCon in USA (based on chitosan). 

Strength of glass fibre/NR composites can be improved by modification of NR and glass fibre. Modified NR can also give higher strength and better adhesion properties. Modification of glass fibre helps to improve the fibre/matrix adhesion. It is discussed very shortly in this section. 

The multiple surface groups present on the surface of the fibre (as a consequence of the dendritic branching) may offer multiple points for interaction with other species (e.g. other nanostructures or biological systems) this may give rise to gels with good adhesive properties. 

Increase in the surface area of fibre, enhances the fibre matrix adhesion and contributing to the improvement of mechanical properties. Grafting of fiber increases the adhesion property of fiber with matrix and its composites showed improved mechanical properties (Table 22.12) [105]. 

Licea-Claverie and co-workers [57] studied mechanical stress-strain, impact properties and also thermal properties of PA 6,6 (including some recycled PA) with mixed glass fibre and carbon fibre reinforcements and compared these properties with those of the virgin polymers. No dependence on mechanical properties because of increasing amounts of scrap in the composites was found up to 10.4 wt%. The recycled composites generally showed lower mechanical properties when compared with the virgin composites because of a poor matrix-fibre adhesion. 

This book presents coverage of the dynamics, preparation, application and physico-chemical properties of polymer solutions and colloids. It also covers the adsorption characteristics at and the adhesion properties of polymer surfaces. It is written by 23 contemporary experts within their field. Main headings include Structural ordering in polymer solutions Influence of surface Structure on polymer surface behaviour Advances in preparations and appUcations of polymeric microspheres Latex particle heterogeneity origins, detection, and consequences Electrokinetic behaviour of polymer colloids Interaction of polymer latices with other inorganic colloids Thermodynamic and kinetic aspects of bridging flocculation Metal complexation in polymer systems Adsorption of quaternary ammonium compounds art polymer surfaces Adsorption onto polytetrafluoroethylene from aqueous solutions Adsorption from polymer mixtures at the interface with solids Polymer adsorption at oxide surface Preparation of oxide-coated cellulose fibre The evaluation of acid-base properties of polymer surfaces by wettability measurements. Each chapter is well referenced. 

Compared with the other thermosetting resins, phenolic resins are much less flanunable and produce less smoke when submitted to fire or intense heat. Furthermore, these resins are relatively inexpensive, have good dimensional stability and retain their adhesive properties at relatively higher temperatures. However, with typical viscosity ranging from 2000 to 5000 cP (Bogner et al., 2000), phenolics are much more difficult to reinforce and cure than other thermosets. Slower processing speeds are required and the water released due to polycondensation has to be properly eliminated, otherwise the bond with the fibre reinforcement will be affected. Furthermore, these resins are a brownish colour and are difficult to pigment (Bank, 2006). Because of... 

From a conceptual point of view, welded connections seem to be the most suitable method to join composite materials, with potential economic and technical advantages. However, the use of this technique is restricted to FRP materials containing thermoplastic resins which, as previously discussed, are more limited technically than thermoset resins (in terms of fibre adhesion and impregnation, processing and mechanical properties). Therefore, this technique is not often used in civil engineering applications. 

The general process used to synthesise aromatic polybenzimidazoles (PBIs) is presented in Section 4.3.3. More detailed information can be found in previously published books [87,88]. During 1960-1970 a number of publications, comparable to those on polyimides, reported the synthesis and properties of all aromatic and aryl-aliphatic polybenzimidazoles. Most of these polymers were prepared by the two-step process illustrated in Fig. 14 with the reaction of 1,3-benzenedicar-boxylic acid diphenyl ester 27 and [l,l -biphenyl]-3,3, 4,4 -tetramine 11 yielding ultimately PBI 29. All the applications - laminates and filament winding resins, adhesives, fibres and foams - used polymer 29, which was produced in semicommercial quantities by the Whittaker Corporation (Narmco Division) under the generic trade mark Imidite . Currently, forty years later, this polymer is manufactured by Hoechst-Celanese and its only commercial success is in the area of heat resistant fibres and fabrics. It is, however, worth noting the adhesive properties of this polymer and the reasons explaining the major obstacles to the development of PBIs as heat-resistant adhesives. 

The two most important nylon fibres are nylon 6 (made from e-caprolactam) and nylon 6,6 (made from hexamethylenediamine and adipic acid). They have moderately high tensile strength, limited modulus, excellent toughness, abrasion resistance, recovery and adhesive properties, and melting temperatures of about 220°C and 250°C respectively. Nylon 6,6 was at one time widely used in tyre cords and other flexible composites, but polyester and steel, on grounds of cost and modulus, have largely displaced it except for certain heavy-duty and aircraft tyres. 

Para-aramid fibres inherently have relatively poor surface adhesion properties unless pre-treated, but are available from the producers with enhanced adhesive properties. A particularly important feature of their mechanical behaviour is that beyond a certain flexural couple they undergo failure by fibrillation on the strained outer side and by a crushing mechanism, involving formation of kink bands in the structure, on the compressed inner side. This behaviour does not result in rupture, as observed with a brittle fibre, and therefore permits retention of some mechanical strength in the reinforcing material. 

This class of fibre is melt-spun from a nematic liquid-crystalline phase, which leads to the production of highly-oriented filaments at quite low elongational shear rates. The fibres have high modulus and, if thermally post-treated over an extended period to raise the molecular weight, they also have very high tensile strength. However, so far they are limited as additives by their fusibility and poor adhesive properties. 

Balnois, E., Busnel, F., Baley, G., and Grohens, Y. (2007) An AFM study of the effect of chemical treatments on the surface microstructure and adhesion properties of flax fibres. Compos. Interfaces, 14, 715-731. 

J. Schultz, L. Lavielle and H. Simon, Surface and Adhesion Properties of Carbon Fibres, Proc. Int. Symp. on the Science and New Applications of Carbon Fibers 84, Toyohashi University of Technology, Japan. 1984. p. 125. 

Copolymerisation of vinyl acetate and vinyl chloride yields resins of desirable properties they are strong and adhesive, thermoplastic, and are suitable for the manufacture of synthetic fibre (Vinyon). 

Today a very wide range of acrylic materials is available with a broad property spectrum. The word acrylic, often used as a noun as well as an adjective in everyday use, can mean quite different things to different people. In the plastics industry it is commonly taken to mean poly(methyl methacrylate) plastics, but the word has different meanings, to the fibre chemist and to those working in the paint and adhesives industries. Unless care is taken this may be a source of some confusion. 

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