Impregnated fibres

Polymerisation casting involves mixing monomer or low molecular weight polymer with a polymerisation initiator, pouring the mix into the mould and allowing polymerisation to occur in situ. A variation is to impregnate fibres with initiated monomer or other low molecular weight material and polymerise to produce composite structures. The main problem is due to the heat of polymerisation. Unless heat transfer distances are kept short or unless the reaction is carried out very slowly it can easily get out of hand. 

Key et al. [27] have described improved methods for the measurement of radon and radium in seawater and marine sediments using manganese dioxide impregnated fibres. The basic method that these workers used was that of Broecker [28]. Seawater samples were taken in 30 litre Niskin bottles. 

The composites obtained were used as reference for the testing of those produced by a Proel patented process (Proel patent n. F191A100, n. 5252265 for USA) of filament-wound curing of resin impregnated fibres [2], This process permits the realization of composites without limits in the thickness using low energy electrons. 

Then the impregnated fibres are squeezed into a long die which is tapered along the passage. This tapering enables... 

Figure 3. Treatment of Tinea Pedis with Socks Containing Copper Impregnated Fibres Healing of diabetic olcers...

Animal studies d onstrated that the copper treated fibers do not possess skin sensitizing properties [1,18]. Furthermore, no individual who used sodks containing copper-impregnated fibres to alleviate their athlete s foot cemditions rqwrted any negative effects caused by the socks [18,19]. Similarly, none of 100 patients, who slept on sheets containii copper treated fibres, reported any adverse effects [18]. These findings are in accordance with the very low risk of adverse skin reactions associated with copper [12]. 

Filament Winding—A reinforced-plastics process that employs a series of continuous, resin-impregnated fibres applied to a mandrel in a predetermined geometrical relationship under controlled tension. 

The resin is generally applied by an impregnation bath, which is mounted on the carriage. The reinforcement passes between bars in the resin bath which spreads the fibre and allows the resin to penetrate the fibre bundle. Alternatively pre-impregnated fibre may be used. 

The idea of confining concrete by winding continuous resin-impregnated fibre strands aroimd RC columns (filament winding) is another technique used for FRP strengthening of RC columns. In this process, an FRP jacket with controlled thickness, fibre direction and volume fraction can be obtained. This procedure is more appropriate for circular columns and usually, special computer-controlled winding machines are used for this purpose. 

Compared to other intermediate product forms such as pre-impregnated tows or powder impregnated fibre bundles, commingled yams are attractive because they possess high flexibility, thus allowing the processing of complex shapes (Svensson et al., 1998). 

Other successful electrochromic devices have been realized by Kelly et al. using polyaniline-impregnated fibres [79]. In situ electrochemical polymerization of polyaniline is used to bind poly aniline to a PET or viscose spacer fabric. The fabric is then impregnated with an electrolyte and sandwiched between two electrodes. For the bottom electrode, carbon black or silver ink can be printed directly on the fabric. Polyaniline colour changes from green to blue through oxidation—reduction processes. However, the lifetime of this structure is also short and does not exceed dozens of oxidation—reduction cycles. 

Another novel pultruded panel has been developed by Mastercore System Ltd., Canada. This could be used in applications such as truck walls, roofs, floors and doors, boat decks, freight containers and sound barriers. The mastercore panel consists of an outer shell of a polyurethane-impregnated fibre carbon/glass fibre hybrid composites with an inner core of a structural foam (Jacob, 2006). 

Factory made cold-melt pre-impregnated fibre (prepreg) and compatible film adhesive which are simultaneously wrapped onto the bridge and cured under an elevated temperature (heat blanket) of 60°C for 16 hours or 80°C for 4 hours under a 1 bar pressure (Hollaway, 2008). 

Phase change materials or plastic crystal-filled or -impregnated fibres... 

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