Polyvinyl fibres

Cells of N. muscorum (permeable) entrapped in the D type foam are shown adhering to the polyvinyl fibres (Fig. 1). 

This includes wire enamels on a base of polyvinyl formal, polyurethane or epoxy resins as well as moulding powder plastics on phenol-formaldehyde and similar binders, with cellulose fillers, laminated plastics on paper and cotton cloth base, triacetate cellulose films, films and fibres of polyethylene terephthalate. 

The use of coatings applied in the form of tape is also increasing. Polyethylene and polyvinyl chloride films, either self adhesive or else supporting films of butyl adhesive, petrolatum or butyl mastic are in use as materials applied cold at ambient temperatures. Woven glass fibre or nylon bandage is also used to support films of filled asphalt or coal tar and these are softened by propane gas torches and applied to the steel surface hot, cooling to form a thick conforming adherent layer. 

Before World War II, German developed a synthetic fibre from polyvinyl chloride. In America, a copolymer of vinyl chloride and vinyl acetate was marketed as Vinyon . Dow chemical marketed as Saran a copolymer from vinylidene chloride and vinyl chloride. Saran fibre is characterised by its remarkable resistance of most of chemical reagents and fire. 

These are the linear or slightly branched long ehaln moleeules capable of repeatedly softening on heating and hardening on eoolmg. These polymers possess intermolecular forces of attraetlon intermediate between elastomers and fibres. Some eommon thermoplastics are polythene, polystyrene, polyvinyls, etc. 

Many of the remarks made in the previous section concerning fibres can be applied to the analysis of plastics. Some polymers are soluble in organic solvents and samples may be prepared for direct aspiration into a flame in this way, e.g. MIBK is a suitable solvent for polyesters, polystyrene, polysiloxanes, cellulose acetate and butyrate dimethyl formamide for polyacrylonitrile, dimethyl acetamide for polycarbonates and polyvinyl chloride cyclohexanone for polyvinyl chloride and polyvinyl acetate formic acid for polyamides and methanol for polyethers. These organic solutions may alternatively be injected into a graphite furnace. Otherwise, polymers may be wet or dry ashed and the resultant ash dissolved in acid. An approach which is attracting increasing interest is the direct insertion of solid samples into a graphite furnace. 

Most vinyl acetate is converted into polyvinyl acetate (PVA) which is used in the manufacture of dispersions for paints and binders and as a raw material for paints. It is also copolymerized with vinyl chloride and ethylene and to a lesser extent with acrylic esters. A substantial proportion of vinyl acetate is converted into polyvinyl alcohol by saponification or transesterification of polyvinyl acetate. The main applications for polyvinyl alcohol are either as raw material for adhesives or for fibres. It is also employed in textile finishing and paper glueing, and as a dispersion agent (protective colloid). The world production capacity of PVA was 4.35 Mt/a in 2005, of which 2.1 Mt were converted into polyvinyl alcohol. 

Exhibits high adhesion to synthetic fibres and is particularly recommended for use on continuous filamant acetate. In conjunction with starch, SCMC or polyvinyl alcohol it is an excellent adhesion promoter for the sizing of staple synthetic fibres and their blends with cellulosics. 

Figure 4-10. Schemetic diagram of events causing detergency [7], oriented soap molecules assumes a net negative charge similar to the globular micelle of soap. Cotton fibres also take up a negative charge when immersed in water. The electrostatic repulsions between the particles and the fibre play a major role in preventing redeposition. The addition of carboxymethyl cellulose (CMC) and/or polyvinyl pyrolidone (PVP) (Fig. 4-11) can act as anti-redeposition agents.

For blended fabrics with cellulosic fibres it is possible to produce heat-embossed blend fabrics with 25% polyvinyl chloride fibres. Heat treatment is carried out by one passage on pin-stenter without overfeed at 85-90 C, and if for example a 15-17% shrinkage is to be achieved, the speed of travel is about 10 m/min. 

Table 8.1 Frotte reagents and reactions (according to Stratmann except acetylated polyvinyl alcohol fibres)...

When making very dehcate materials it may be necessary to use a yam which is so fine that it would break down under the stresses imposed on it during manufacture. The strength, however, is sufficient once the fabric is made because of the mutual support of adjacent threads. In such cases it is customary to impart temporary strength to the yam by a process known as sizing. This consists of impregnating the thread with some easily removed substance such as starch or dextrine and, in the case of the more modern man-made fibres, with a synthetic product such as polyvinyl alcohol or polyacrylic acid. The size is usually removed before the article is dyed or bleached. Yarns are frequently referred to as warp or weft yarns. In a... 

Polyvinyl chloride, alcohol, acetate, and their copolymers are used to a limited extent for fibre production. They are cheap because the monomers are easily prepared from ethylene or acetylene, both of which are available in abundance. The fibres have not been used much for textiles, however, because they soften at temperatures varying between 50 and 100°C, according to the composition of the polymer. 

Pure polyvinyl chloride is the composition of PCU, produced in Germany, and of Rhovyl and Thermovyl, made in France. PCU loses its mechanical stability and shrinks considerably, due to the stretched molecules resuming their original configurations, at temperatures of 75 to 80 C. It compares unfavourably, therefore, with other synthetic fibres for textile uses. It has found certain specialized applications for making fishing lines, filter cloths, and sails. 

Thermo- and Photooxidative Destruction of Dyed Polyvinyl - Alcohol Fibres... 

In order to determine the sources of contamination, some water samples, including wastewaters and effluents from different industries, were also taken. Along the Cinca River and in the industrial area of Monzon, industrial effluents from two different industries were selected the first one produced EPS (expandable polystyrene) treated with flame retardants and ABS (acrylonitrile-butadiene-styrene), and the second one produced PVC (polyvinyl chloride). As regards the Vero River, three industries were sampled the first one was a textile industry which produced polyester fibres treated with flame retardants, the second produced epoxy resins, and the third focused on polyamide polymerisation. 

AGM — membrane sandwich. The combination of a membrane with an AGM separator has been investigated with a view towards controlling the oxygen transport as well as improving the compressive properties of the separator. With reference to the latter aspect, a AGM-membrane sandwich has been evaluated [19]. The AGM consisted of 100% fine fibres, and the incompressible polymer membrane was a mixture of polyvinyl chloride and 5-10 wt.% silica, which was partly extracted to increase the pore size and porosity. The properties of the two separator components are summarized in Table 7.9 [22]. 

After 1950, the rapid growth of petroleum and methane based production of plastics and synthetic fibres became the most prominent feature of the Italian chemical industry/ Montedison, created in 1966 through a merger between the electrical company Edison and Montecatini, in that year produced between 50 and 100 per cent of Italy s aromatics, polyethylene, polypropylene, acrylic fibres, PVC and polyesters." Such a remarkable performance may appear surprising, considering that up to 1950 Montecatini s experience in polymerization had been mainly confined to the more traditional phenol plastics (Bakelite, etc.) and urea-formaldehyde resins (Caurit, etc.). The production of polyvinyl resins and the polyamide fibre nylon had been experimental rather than continuous." The most advanced polymerization procedures... 

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