Rubber INDEX

While studying polymer distribution between the emulsion phases it was found that in the systems mentioned above obtained both by copolymerization of styrene with polybutadiene rubber and mixing styrene solutions of polymers when the composition is far enough from the critical mixing point, thermodynamic equilibrium is reached.At this thermodynamic equilibrium the ratio of polymer concentration (Cp) in rubber (index ) as well as in polystyrene (index ) phases is practically constant (table II),... 

In the rubber industry a double parallel plate device, the Mooney Wscometer (ASTM D1646) is used to measure viscosity, Data is normally reported in Mooney units fi om 0 to 100, but these can be translated to torque and analyzed by eq. 5.5.8 (Naka-jima and Collins, 1974). Another rubber indexer is the oscillating disk curometer, which is typically a bicone oscillating at 3 Hz in a disk-shaped cavity (ASTM D2704). Peak torque is reported on a scale of 0-100, but if the amplitude is known, this can be translated to G. However, at high G levels and the usual operating conditions wall slip can occur. 

R. C. Weast and M. J. Asde, eds.. Handbook of Chemisty andPhysics, 62nd ed.. Chemical Rubber Company, Boca Raton, Fla., 1981, p. D-101 S. Budavari and co-eds.. The Merck Index, 11th ed., Merck, Rahway, N.J., 1989, p. MISC-53. 

The gel content (toluene insoluble per cent) of the rubber and the swelling index of the gel (the ratio of the volume of a swollen gel to its unswollen volume). The former is a measure of the amount of cross-linked material and the second a measure of the intensity of cross-linking. It has been found that a sample of medium gel content (5-20%) and a medium swelling index (10-20) gives the best impact strength in the blend. 

There are some aspects in the raw dry NR grades for adhesive manufacturing to be considered. NR tends to suffer oxidative degradation catalyzed by metals (mainly copper). The susceptibility of NR to oxidation can be measured using the plasticity retention index. The better grades of rubber have the higher plasticity retention index. 

Solubility of resins can be predicted in a similar way as for the solubility of polychloroprene rubbers in a solvent mixture (see Section 5.5) by means of solubility diagrams (plots of the hydrogen bonding index (y) against the solubility parameter (5). Another more simple way to determine the solubility of resins is the determination of the cloud point, the aniline and the mixed aniline points. 

Figure 14 Variation of power law index (n) with the percent Thiokol rubber in NBR-Thiokol blends.

Degussa AG (2003) Vestenamer - the rubber with unique properties. Company publication, available viahttp //www.degussa-hpp.de/e/index.html... 

There is also a fourth division of Beilstein (systems 4721 -4877) that covers natural products of uncertain structure rubbers, sugars, and so on. These are treated in vols. 30 and 31, which do not go beyond 1935 and which are covered in the collective indexes. These volumes will not be updated. All such compounds are now included in the regular Beilstein volumes. 

The blends, irrespective of the concentration of fluororubber, show surface energy lower than neat rubbers. This is attributed to the migration of silicone mbber to the surface. The presence of silicone rubber on the surface of the blends also contributes to their lower limited oxygen index compared to that of fluoroelastomers. 

Mechanical Properties and Cure Rate Index of the Mixes—Role of Dry Bonding System on the Reinforcement of Ethylene-Propylene-Diene Monomer (EPDM) Rubber with Melamine Fiber ... 

Notice that the carbon black hller reduces the rate of cut growth, but has only a small effect on the power index. Generally, it appears that abrasion occurs mainly in the third region, except when the abrasive track is very sharp. In this case the number of cycles to detach a small piece of rubber becomes small and the abrasion is proportional to the reciprocal of the energy density at break of the rubber compound. 

Aryloxyphosphazene copolymers can also confer fireproof properties to flammable materials when blended. Dieck [591] have used the copolymers III, and IV containing small amounts of reactive unsaturated groups to prepare blends with compatible organic polymers crosslinkable by the same mechanism which crosslinks the polyphosphazene, e.g. ethylene-propylene and butadiene-acrylonitrile copolymers, poly(vinyl chloride), unsaturated urethane rubber. These blends were used to prepare foams exhibiting excellent fire retardance and producing low smoke levels or no smoke when heated in an open flame. Oxygen index values of 27-56 were obtained. 

The intensity of scattering of light by a swollen network is related to two factors. One of these is the mean square fluctuation in refractive index which is proportional to the mean squared fluctuation in Mc, with a proportionality constant determined by the difference in refractive index between the rubber and the diluent. The second is the... 

MgC03 is used as a reinforcing filler for white and light-coloured rubber stocks. Certain types have almost the same refractive index as rubber and are therefore useful in making transparent and translucent vulcanisates. 

The symbol for micron (pan), for refractive index and for coefficient of friction. A high mu rubber (fomerly termed high hysteresis, high energy-loss or cling rubber) is one specially developed for the wearing surface of pneumatic tyre treads to improve road holding. 

Another term for plasticity retention index. Viscosity-Stabilised Natural Rubber... 

Figure 5. Effect of tin compounds on oxygen index vs. temperature of ethylene-acrylic rubber containing 50% ATH. Key 0, 2.5% ZnSn(OH)6 , 2.5% Sn02 O. no tin.

It is of interest to note that the polymer containing ZnSn(OH) does not burn in air even at 250°C and, accordingly, this composition has a temperature index of at least 50°C above that of the rubber containing ATH alone. The 01 and high temperature 01 data therefore provide substantial evidence as to the benefit of using ZnSn(OH) as a flame-retardant synergist with alumina trihydrate filler. 

Electrically conductive rubber, 20 247 Electrically conductive resins, 7 7 840 Electrically stimulated drug delivery systems, 9 59-61, 81 Electrical mineral size reduction, 76 613 Electrical Patents Index (EPI), 18 222 Electrical properties... 

Saturable dye absorber, 14 677 Saturated aqueous salt solution, 9 34 Saturated calomel electrode (SCE), 9 571 Saturated fatty acids, 10 829, 830 Saturated hydrocarbons adsorbent affinity, 1 674 adsorption by zeolites, 1 624 fluorine reactivity with, 11 831 isomerization of, 12 172—173 Saturated polyester resins, based on trimethylpentanediol, 12 673 Saturated polyesters, 10 7 Saturated synthetic rubber, 10 705 Saturation and coating processes, 10 12-13 Saturation bonding, 17 509-510 Saturation color, 19 262 Saturation concentration, 15 677 Saturation index... 

---