Vulcanized fibre

Rubber from trees has been used in both solid and latex form, and also converted further into isomerized and chlorinated polymers of very different properties and uses. Wood from trees is used directly for plywood, composition board, and wood-flour reinforcement of phenolic resins. The cellulose from wood is purified and used for laminates and for regenerated cellulose products such as cellophane, viscose rayon, and vulcanized fibre. The lignin from wood has been explored for use in plastics, but never carried through to complete commercial success. 

Vulcanized fiber [ff. Vulcanized Fibre, a trademark] (ca. 1884) n. Cellulosic material that has been partly gelatinized by action of a chemical (usually zinc chloride solution), then heavily compressed or rolled to the required thickness, leached free of the zinc chloride, and dried. It has been used for electrical insulation, luggage, and mate-rials-handling equipment. 

VULCANIZED FIBRE-RIGID PVC-ACRYLIC RESIN POLYCARBONATE-POLYAMIDE-... 

UL 746E Polymeric Materials— Industrial Laminates, Filament Wound Tubing, Vulcanized Fibre,... 

There are many references in the patent literature to azo dyes prepared from 4- and 5-aminoisothiazoles, 3-, 5- and 7-amino-1,2-benzisothiazoles, and their quaternized derivatives. These are particularly useful in the dyeing of synthetic fibres. Isothiazole compounds have also been suggested for other industrial purposes, such as corrosion inhibitors, fireproofing agents, additives in rubber vulcanization, photographic chemicals and fluorescent whiteners in detergents. 

Modified PAN fibres have been obtained from copolymers containing up to 15% or ISP units using the wet spinning process30. Some properties of modified fibres are presented in Table 1. For comparison are also given the properties of fibres obtained from copolymers additionally crosslinked with conventional crosslinking agents used in the vulcanization of nitrile rubbers. 

A comparatively new group of materials— thermoplastic elastomers or thermoplastic rubbers —combines the ease of processing of thermoplastics with qualities of traditional vulcanized rubbers, especially elasticity. Because of convenience in processing there is much interest too in blends of plastics with elastomers, which may be modified by the inclusion of filler or glass fibre. As an example, a rubber-like material that can be processed as a thermoplastic can be made by blending and melt-mixing an ethylene-propylene rubber with polypropylene. The use of such blends may be helpful when there are needs to reclaim and re-process material, and in order to obtain products with qualities intermediate between those of the main components of the blends. 

The sulfonimide (238) has been copolymerized with CH2=CHCN and CH2=C(Me)C02Me to produce a useful fibre (75GEP2346566), and the bis(oxathiazolone) (239), as a nitrile sulfide precursor (Scheme 5), has been used in the vulcanization of SBR... 

Only types (l)-(4) fall within the scope of this chapter. No further reference will be made to emulsion-polymerized prolybutadiene rubbers, because they are now of little industrial significance relative to the styrene-butadiene rubbers. Poly(vinyl chloride) is discussed elsewhere in this book. Brief reference will also be made in this chapter (Section 15.5) to the production and properties of carboxylated variants of styrene-butadiene rubber latexes. It may also be noted that latexes of rubbery terpolymers of styrene, vinyl pyridine and butadiene, produced by emulsion polymerization, have long been of considerable industrial importance for the specialized application of treating textile fibres (e.g., tyre cords) in order to improve adhesion between the fibres and a matrix of vulcanized rubber in which they are subsequently to be embedded. 

The chemical industry s interest in polymers dates back to the 19th century. In those days it was a case of synthetically modifying natural polymers with chemical reagents to either improve their properties or produce new materials with desirable characteristics. Notable examples were nitration of cellulose giving the explosive nitrocellulose, production of regenerated cellulose (rayon or artificial silk) via its xanthate derivative, and vulcanization of rubber by heating with sulphur. Manufacture of acetylated cellulose (cellulose acetate or acetate rayon) developed rapidly from 1914 onwards with its use both as a semi-synthetic fibre and as a thermoplastic material for extrusion as a film. 

The possible mechanism of grafting maleated sulfur pre-vulcanized NR (M-SPNR) with cellulose fibre by using benzyl peroxide (BPO) and K2S2O8 at 80 °C is shown in Figure 13.21. Free radicals from BPO activate the carbon-carbon double bonds of MA, which then react with carbon arbon double bonds of SPNR molecules activated by K2S2O8 to form the M-SPNR. When the M-SPNR reacts with cellulose fibre, the M-SPNR-g-cellulose fibre is... 

Examples of the use of blocked diisocyanates for rubber-fabric adhesion are as follows vulcanized polychloroprene and SBR can be adhered strongly to nylon and polyester fibre fabric by means of aqueous adhesive systems (Table 8.4). This combination is spread or roller coated on to the fabric which is then allowed to dry. Bonds to sheet rubber stock can be made immediately after the treated fabric is dried or at any time thereafter. When the sheet rubber is applied it should be held under moderate pressure to provide intimate contact with the treated fabric and to prevent lifting if any gases are emitted during cure. Press cures of 20-40 min at 140°C are sufficient to cure the adhesive and most elastomer compositions being adhered. If a latex film is applied to the treated fabric, the assembly can be cured in a hot-air oven at 120"C. A chemical bond results between fabric and the diphenylmethane-/7,/ -diisocyanate generated on the thermal cleavage of the blocked diisocyanate. 

The early history of polymers is really the conversion of natural polymers into useful materials. Examples include the vulcanization of rubber (Goodyear, 1839), celluloid (which is plasticized cellulose nitrate—Hyatt, 1868), and cellulose-derived fibres, e.g. cuprammonia rayon (Despeisses, 1890) and viscose rayon (Cross, Bevan and Beadle, 1892). The first truly synthetic polymer, that is, one made from laboratory chemicals, was Bakelite (Bakeland, 1907). This was made from phenol and formaldehyde. Bakeland probably did not know the chemical structure of the Bakelite, but he did realize that organic chemicals containing multiple functionality yielded insoluble materials. The various phenol-formaldehyde resins (PF), e.g. Bakelite and novolacs, were thus obtained in an empirical manner. 

Vetiver Oil essence de vetyver Viscose viscose Vitamin vitamine B2 Vitamin D vitamine D Vulcanized Fiber fibres vulcanisdes... 

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