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Unvulcanised rubbers

ASTM D6048, 2002. Stress relaxation testing of raw rubber, unvulcanised rubber compounds and thermoplastic elastomers. [Pg.94]

Mention may here be made of the fact that natural unvulcanised rubber is poly-isoprene (2-methylbutadiene) ... [Pg.1022]

Tables 5.4 and 5.5 predict that unvulcanised natural rubber (8 = 16.5) will be dissolved in toluene (8 = 18.2) and in carbon tetrachloride (8 = 17.5) but not in ethanol (8 = 26.0), all values being in units ofMPa. This is found to be true. Similarly it is found that there is a wide range of solvents for polystyrene in the solubility parameter range 17.2-19.7 MPa. ... Tables 5.4 and 5.5 predict that unvulcanised natural rubber (8 = 16.5) will be dissolved in toluene (8 = 18.2) and in carbon tetrachloride (8 = 17.5) but not in ethanol (8 = 26.0), all values being in units ofMPa. This is found to be true. Similarly it is found that there is a wide range of solvents for polystyrene in the solubility parameter range 17.2-19.7 MPa. ...
Like NR, SBR is an unsaturated hydrocarbon polymer. Hence unvulcanised compounds will dissolve in most hydrocarbon solvents and other liquids of similar solubility parameter, whilst vulcanised stocks will swell extensively. Both materials will also undergo many olefinic-type reactions such as oxidation, ozone attack, halogenation, hydrohalogenation and so on, although the activity and detailed reactions differ because of the presence of the adjacent methyl group to the double bond in the natural rubber molecule. Both rubbers may be reinforced by carbon black and neither can be classed as heat-resisting rubbers. [Pg.292]

The lining sheet is prepared by calendering in thin plies up to 1 mm in thickness, followed by combining the individual layers on the calender to form a finished sheet, usually between 3 mm and 6 mm thick. Alternatively, lining sheet can be manufactured by the roller die process in which the sheet is extruded and then passed through rollers to give the finished thickness. Extrusion is also used for the preparation of unvulcanised rubber tubes suitable for lining pipes up to 200 mm in diameter. [Pg.946]

In principle, any type of sample can be analysed by SEC provided that it can be solubilised and that there are no enthalpic interactions between sample and packing material. By definition then, this technique cannot be carried out on vulcanisates and even unvulcanised fully compounded rubber samples can present problems due to filler-rubber interactions. The primary use of SEC is to determine the whole MWD of polymers and the various averages (number, viscosity, weight, z-average) based on a calibration curve and to allow qualitative comparisons of different samples. Many commercial polymers have a broad MWD leading to strong peak overlap in the chromatography of complex multicomponent systems. [Pg.261]

Moore [231] has used hybrid MS/MS (EBQQ geometry El spectra) for the direct analysis of DODPA in unvulcanised rubber. Particular advantages of the technique are ... [Pg.405]

Unreacted free sulfur can be determined to ISO 7269 1995 — Rubber — Determination of free sulfur. Three methods for the determination of free sulfur in vulcanized rubber are detailed two versions of the copper spiral method and the sodium sulfite method. The copper spiral methods are also applicable, subject to limitations, to unvulcanised rubber. The technique of DSC can detect non-reacted rubber curatives such as residual peroxides. [Pg.586]

The rubber in unvulcanised filler-rubber mixes which is insoluble in a usual rubber solvent. Bonding Agent... [Pg.14]

Bound rubber in an unvulcanised carbon black-rubber mix. It results from the production of free radicals in the mastication of rubber these radicals attach themselves chemically to the particles of carbon black and form a proportion of carbon gel which is insoluble in the usual rubber solvents. [Pg.16]

Rubber which is deliberately rendered electrically conductive by the inclusion in the unvulcanised mix of certain types of carbon black. Conductive rubber for use in, e.g., aircraft tyres has a resistivity below about 105 to 107 ohm-cm. The changeover from the use of channel blacks to oil-based furnace blacks has conferred a degree of conductivity (sometimes unwanted) on many black rubber products, and it should no longer be assumed that any black rubber is a good electrical insulator. See Antistatic Rubber. [Pg.19]

A calendering process in which hot soft unvulcanised rubber compound is applied to a fabric. The cloth passes between the bottom and middle bowls of a three-bowl calender it travels at the speed of the bottom bowl and the faster middle bowl shears the rubber into the pores of the fabric. [Pg.30]

A textile material used to prevent the tacky surfaces of unvulcanised rubber from adhering. The liner is often treated to permit easy release from the rubber. [Pg.37]

An instrument which determines the viscosity of unvulcanised elastomers by measuring the resistance of the rubber to the shearing action resulting from the motion of a rotor in the centre of the test piece (BS 903-A58). [Pg.41]

General name for mixtures of liquid hydrocarbons obtained from petroleum, coal tar or shale, used as solvents for unvulcanised rubber. [Pg.42]

Unvulcanised rubber in the form of granules. It is used for dissolving in hot bitumen for making the surfaces of so-called rubberised roads Power Factor... [Pg.50]

Indicates the ability of an unvulcanised rubber compound to accept the heat history required in processing without risk of scorching. [Pg.50]

Unvulcanised natural rubber which has been cooled quickly while under tension. In this condition it behaves like a relatively inextensible fibrous material. [Pg.51]

The process of roughening the surface of vulcanised rubber preparatory to applying a layer of unvulcanised rubber as in tyre re-treading, conveyor-belt repairing, etc. [Pg.52]

A term which generally applies to vulcanised rubber unfit for any other use than reclaiming or grinding to crumb rubber. In the rubber factory scrap may also refer to unvulcanised trimmings which can be reprocessed. [Pg.56]

The time during which an unvulcanised rubber compound (e.g., tyre, tube and belting repair materials) or a vulcanised rubber product will remain usable when stored under normal atmospheric conditions of temperature and humidity. [Pg.57]

Change in dimensions of an unvulcanised rubber (calendered sheet or extruded section) on cooling from the processing temperature. Also the volume contraction of a moulded rubber product on cooling from vulcanising temperature. See Coefficient of Thermal Expansion (Volumej. Shrinking... [Pg.57]

The process of controlled, gentle warming of unvulcanised calendered sheet rubber to reduce its anisotropy and prevent subsequent distortion of articles made from the sheet and cured by embedding in chalk in open steam. [Pg.57]

Crepe rubber which has been plied up to thicknesses of 1/8 in, 3/16 in or 1/4 in and used in the soling of footwear. It has now been almost entirely superseded by a vulcanised rubber of similar appearance to that of the unvulcanised crepe. [Pg.58]

Wet anti-tack agents can be soap or detergent solutions or suspensions of the dry agents in water. For example, dissolved polymers with non-ionic surface active agents which form a thin layer of polymer on unvulcanised rubber sheets magnesium stearate in water zinc stearate dispersion and aqueous dispersions of fatty acid salts. [Pg.141]

Sulphur in its amorphous form is known in the rubber industry as insoluble sulphur . Insoluble sulphur is used by the rubber industry as, if not converted to the rhombic form by excessive processing heat, it will remain undissolved in the rubber and thus cannot bloom to the surface of the unvulcanised rubber compound. This is a factor which is very important for products which require a number of processing assembly steps in their manufacture. [Pg.162]

Marking devices are available which impress identification into the surface of the unvulcanised rubber slabs. Other devices can continuously apply an identification to extrudates on emergence from the die. [Pg.193]

A pre-cured tread with pattern is prepared by moulding. A thin strip of unvulcanised cushion rubber compound is inserted between the casing and the tread rubber to form the bonding agent between the new and old components. The tread is then applied to the casing and consolidated by pressure. The cushion rubber is then vulcanised. This is also known as cold retreading . [Pg.205]


See other pages where Unvulcanised rubbers is mentioned: [Pg.927]    [Pg.956]    [Pg.392]    [Pg.401]    [Pg.407]    [Pg.927]    [Pg.956]    [Pg.392]    [Pg.401]    [Pg.407]    [Pg.282]    [Pg.288]    [Pg.289]    [Pg.293]    [Pg.302]    [Pg.306]    [Pg.74]    [Pg.18]    [Pg.24]    [Pg.41]    [Pg.67]    [Pg.142]    [Pg.148]    [Pg.155]    [Pg.161]    [Pg.200]   
See also in sourсe #XX -- [ Pg.150 ]




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