Fibres organic precursor

The production of carbon fibres is based on the pyrolysis of organic fibres or precursors. The main starting materials are polyacrylonitrile (PAN) and pitch (coal tar or petroleum asphalt). They can be classified according to their mechanical performances ... 

Carbon Fibres—Fibres produced by the pyrolysis of organic precursor fibres such as rayon, polyacrylonitrile (PAN), or pitch in an inert atmosphere. The term is often used interchangeably with graphite . However, carbon fibres and graphite fibres differ in the temperature at which the fibres are made and heat-treated, and the carbon content. 

CaCOa/wood cellulose nanocomposite materials have been prepared by controlled generation of carbonate in aqueous solution from an organic precursor (DMC) in the presence of wood cellulose fibres and CaCL [65]. The work demonstrated that the quantity and morphology of CaCOa particles deposited at the surface of cellulose fibres were strongly influenced by the hydrolysis conditions. The amount and size of CaCOa deposited on the cellulose fibres increased with increasing reaction time. Besides, the reactions performed at room temperature originated... 

The conversion of the organic precursor into carbon should yield a high-coke residue and low-volume shrinkage during the pyrolysis. Furthermore, no fibre or matrix damage during the carbonization should occur. One has to distinguish between two... 

Fibre which is produced by high temperature treatment of an organic precursor fibre based on polyacrylonitrile (PAN), rayon or pitch in an inert atmosphere at temperatures above 1000 °C. It is a reinforcing fibre known for its light weight, high strength and stiffness. 

A number of different grades of carbon fibre are manufactured, but all are made by the thermal degradation of a polymeric organic precursor. Commercial production of carbon fibres uses three carbon-containing precursors ... 

Turning now to other types of ceramic fibre, the most important material made by pyrolysis of organic polymer precursors is silicon carbide fibre. This is commonly made from a poly(diorgano)silane precursor, as described in detail by Riedel (1996) and more concisely by Chawla (1998). Silicon nitride fibres are also made by this sort of approach. Much of this work originates in Japan, where Yajima (1976) was a notable pioneer. 

The production process of activated carbon fibre consists of the development of amorphous carbon flbres at around 1000°C from fibre precursors, followed by physical activation either by steam at 800-1000°C or chemical activation. The organic fibre precursors include polyvinylidene chloride (PVDC) fibres (Saran), phenolic fibres (Kynol) , poly (acrylamide), polyacrylonitrile (PAN) and rayon fibres activated carbon fibres can also be made from vapour-grown fibres, nanotubes and... 

Carbon fibres are obtained from different organic fibres (precursors) by pyrolysis, which consists of decomposition into smaller molecules at high temperature. The process of fabrication of carbon fibres from special PAN fibres includes two steps oxidative stabilization at low temperature and carbonization at high temperature in an inert atmosphere. Due to the high cost of raw materials (e.g. PAN fibres) and of this production process, carbon fibres are still expensive. Carbon fibres may be also produced from crude oil deposits like pitches or asphalts. Three main groups of carbon fibres are considered as possible composite materials reinforcement ... 

Piezoceramic materials are chemically inert and physically strong. In fibre form, they have anisotropic structures. Usually, ceramic fibres are produced by the spinning of an organic or mineral precursor fibre, followed by heat treatment and pyrolysis (Hearle, 2001). Piezoceramic fibres comprising lead zirconate/lead titanate exhibit better sensitivity in terms of piezoelectric activity and elevated operating temperatures (Swallow et al., 2008). PZT fibres can be manufactured by various processes, such as sol-gel, viscous suspension spinning, extrusion and viscous plastic processing, some of which are already commercially available (Strock et al., 1999 Meyer et al., 1998 French and Cass, 1998 Meister et al., 2003 Bowen et al., 2006). 

The chain of reactions involved in muscle contraction, from the signal at the neuro-muscular junction and the release of calcium by the sarcoplasmic reticulum, to the force development by the contractile apparatus, is currently studied by a wide variety of techniques. These involve experiments with preparations at every level of organization from pure protdns in solution to intact muscle. Some of the important new developments of methods, which can be used for the study of the same reaction step in solution and within cells, have used the contractile system as a paradigm. The application of pressure relaxation to the study of actin-miyosin interaction in solution as well as of tension changes in fibres is discussed in section 6.4. The initiation of reactions by the photochemical release of ATP from inactive precursors, discussed in section 8.4, has provided data for the rates of steps of myosin ATPase in contracting muscle fibres. Many dilferent signals can be used for the kinetic resolution of steps involved in... 

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