Fillers in rubber compounds

CaC03, a white solid which occurs in nature as chalk, limestone and marble the ground product, often termed whiting, is used as an extending filler in rubber compounding. 

Calcium silicate, sodium aluminium silicate and treated varieties of aluminium silicate used as reinforcing fillers in rubber compounding. Silicone Rubber... 

Kim, J.K. Burford, R.P. Study on powder 52. utilization of waste tires as a filler in rubber compounding. Rubber Chem. Technol. 1998, 71, 53. 

A study of twelve silica fillers in rubber compounds showed that all of the fillers contributed to the formation of nitrosamines. There was a substantial difference in the amounts of nitrosamines detected in the presence of different fillers (from 1.1 xl 0 to 14.8x10 mol/kg) but this difference could not be correlated with properties such as their structure or surface area. ... 

Ahmed et al. studied the improved properties of rubber vulcanizates containing white molybdates. The fillers were incorporated into NR formulations indifferent ratios up to 40 phr to study the effect of filler loading on the properties of the vulcanizates. Molybdates can be used as reinforcing fillers in rubber compounds to replace carbon black. Molybdenum is unlike other heavy metals, in that it is non-toxic, has good whiteness, and is reasonably prieed,... 

The basic properties of polymers may be enhanced by physical as well as chemical means. An important example is the use of finely divided carbon black as a filler in rubber compounds. Polymers may be combined with stiffer filaments, such as glass or carbon fibres, to form a composite. We shall show later that some semicrystalline polymers may be treated as composites at a molecular level. 

Reinforcing Filler in Rubber Compounds Paint Rollers Thermal Blankets... 

Raw limestone is used to produce whiting (ground limestone) as an economical diluent filler in rubber compounding. It is also used as a feedstock to manufacture precipitated calcium carbonate, which is also used as a little more costly, but better, filler for extending a rubber formulation. 

The hydrated precipitated silica used with general-purpose elastomers in HRH adhesive systems (and also as fully reinforcing filler in rubber compounding) comes from water glass (sodium silicate). This is made from natural silica (sand) that is reacted either with sodium hydroxide or sodium carbonate at very high temperatures see Figure 8.6. 

Carbon black and silica are well known reinforcing fillers in rubber compounds and these, as well as other fillers, are often used as fillers for polymeric compounds in other industries, such as in thermoplastics, composites, paint, and the like. In rubber, attempts at improving filler dispersion have included high temperature mixing of carbon black-rubber mixtures in the presence of selectively-re-active promoters to promote compounding material reinforcement. Other approaches have, for example, included surface oxidation of the compounding materials or chemical modifications to the ter-... 

Clarke,. 1. and Freakley, P.K., 1995. Modes of dispersive mixing and filler agglomerate size distributions in rubber compounds, Plast. Rubber Compos. Process. Appl. 24, 261-266. 

Diatomaceous earth, a fairly pure silica, formed from the skeletons of minute organisms, known as diatoms. In rubber compounding it is used as an inert filler. 

The mineral muscovite, mainly an orthosilicate of aluminium and potassium, finely ground and used as a lubricant in rubber moulding and as an extended filler in latex compounds. 

An activator in rubber compounds containing organic accelerators. In polychloroprene, zinc oxide is considered to be the accelerator rather than the activator. The use of zinc oxide as a reinforcing agent and as a white colouring agent is obsolescent. Zinc oxide is manufactured by either the French (or indirect) process or by the American (or direct) process. It can be used as a filler to impart high thermal conductivity. 

This filler is mined, ground and sieved to a particle size less than 100 mesh and used as an inert diluent and cheapening filler for rubber compounds. It is usually off-white to cream in colour. Depending upon source, the filler can be contaminated with metal ions, e.g., iron, copper, manganese, which can catalyse oxidation. It can be used in very high loadings with great effect on compound hardness. 

The SEM is also used to do X-ray/elemental analysis. This technique is qualitative. X-ray analysis and mapping of the particular elements present is useful for the identification of inorganic fillers and their dispersion in compounds as well as inorganic impurities in gels or on surfaces and curatives, e.g., aluminum, silicon, or sulfur in rubber compounds and Cl and Br in halobutyl blends. (Figure 9)... 

In the industrial field, modified silica assists the development of advanced materials. Modified silica powders are used as a filler in rubbers and in new-type gas sensors. Most industrial applications involve the use of strongly related materials such as glass fibres or thin Si02 layers. We wish to restrict ourselves to a discussion of the application of powdered silica and a short indication of related compounds. 

Dispersing agent and accelerator activator in rubber compounds. It aids dispersion of pigments and fillers and improves processing since it acts as a stock lubricant and can facilitate mold flow, improve extrusions and aid release. 

Another potential hazard in using fillers is the possible formation of toxic materials. Twelve samples of siliea fillers were studied with respect to their effect on the formation of N-nitrosamines in rubber compounds. Figures 20.1 and 20.2 provide these data. Filler absorption of NO inereases as the fillerk specific surface area increases. This absorbed NO was found to react with amines in rubber and to produee N-nitrosamines. Greater absorption... 

Graphite is a mineral filler, used as an inert filler in general compounding, but is of great importance in rubber lining compounds as it imparts good chemical resistance. It is a... 

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