Reinforcement in elastomers

Kraus, G., Ed. Reinforcement in Elastomers Wiley Interscience New York, 1965. 

Elastomers can be reinforced, or made tougher, by the addition of very small particles, typically finely dispersed carbon blacks or silicas. Similar types of reinforcement in elastomers can be brought about by the addition of a plastic polymeric phase (Sections 4.4 and 8.4) or the inclusion of polystyrene latexes. 

Carbon black represents the most commonly employed elemental pigment used in PVC and perhaps the entire plastics and rubber industry. While more ofien employed as a reinforcement in elastomers, carbon blacks of a wide variety and source are excellent colorants for PVC. Three main classifications of carbon black are channel blacks, furnace blacks and thermal blacks (21). Channel blacks give very good UV stability (63,64), furnace blacks are recommended for electrical insulation (65), and thermal blacks are lowest in cost... 

Theory of Filler Reinforcement in Elastomers Based on Uniform Soft-Sphere Model... 

Sohoni, G. B. Mark, J. E., Anisotropic Reinforcement in Elastomers Containing Magnetic Filler Particles. J. Appl. Polym. Sci. 1987, 34, 2853-2859. 

Mark JE. Some simulations on filler reinforcement in elastomers. Mol Cryst Liq Cryst 2002 374 29-38. 

Ziegel K D and Romanov A (1973) Modulus reinforcement in elastomer composites. I. Inorganic fillers, J Appl Polym Sci 17 1119-1131. 

The study of the mechanical properties of filled elastomer systems is a chaUenging and exciting topic for both fundamental science and industrial application. It is known that the addition of hard particulates to a soft elastomer matrix results in properties that do not follow a straightforward mle of mixtures. Research efforts in this area have shown that the properties of filled elastomers are influenced by the nature of both the filler and the matrix, as well as the interactions between them. Several articles have reviewed the influence of fiUers hke sihca and carbon black on the reinforcement of elastomers.In general, the strucmre-property relationships developed for filled elastomers have evolved into the foUowing major areas FiUer structure, hydrodynamic reinforcement, and interactions between fiUers and elastomers. 

Before dealing with reinforcement of elastomers we have to introduce the basic molecular features of mbber elasticity. Then, we introduce—step-by-step—additional components into the model which consider the influence of reinforcing disordered solid fillers like carbon black or silica within a rabbery matrix. At this point, we will pay special attention to the incorporation of several additional kinds of complex interactions which then come into play polymer-filler and filler-filler interactions. We demonstrate how a model of reinforced elastomers in its present state allows a thorough description of the large-strain materials behavior of reinforced mbbers in several fields of technical applications. In this way we present a thoroughgoing line from molecular mechanisms to industrial applications of reinforced elastomers. 

Exfoliating layered particles such as the clays, mica, or graphite is being used to provide very effective reinforcement of elastomers at loading levels much smaller than in the case of solid particles such as carbon black and silica [228-231]. Other properties can also be substantially improved, including increased resistance to solvents, and reduced permeability and flammability. 

J.E. Mark and D.W. Schaefer, Reinforcement of elastomers by the in-situ generation of filler particles. In D.W. Schaefer and J.E. Mark (Eds.), Polymer-Based Molecular Composites, Materials Research Society, Pittsburgh, 1990, Vol. 171, p. 51. 

Kliippel, M. The Role of Disorder in Filler Reinforcement of Elastomers on Various Length Scales. Vol. 164, pp. 1-86. 

Kevlar fibers are available in four forms Kevlar, Kevlar 29, Kevlar 49 and the recently developed Kevlar 149. Kevlar is designed specifically for reinforcements of elastomers (e.g. tires and belts), while Kevlar 29 is used primarily for tensile members sueh as ropes, cables, webbings and ballistic cloth. Kevlar 49 and 149 are designed for reinforcement of high performance PMCs. Kevlar 149 offers a 40%... 

This most widely used black pigment is also in the top 50 chemicals. About 4.0 billion lb of carbon black were made in 2001. Commercial value was 1.4 billion at 35C/lb, but 93% of this is used for reinforcement of elastomers. Only 7% is used in paints and inks. Carbon black is made by the partial oxidation of residual hydrocarbons from crude oil. See Chapter 6, Section 7.2. The hydrocarbons are usually the heavy by-product residues from petroleum cracking, ideally high in aromatic content and low in sulfur and ash, bp around 260°C. 

The value of TMWV is dependent on the cohesive energy density (CED) of amorphous polymers, the extent of crystallinity in crystalline polymers, and the effect of reinforcements in polymeric composites. Thus, while a low molecular weight amorphous polymer may be satisfactory for use as a coating or adhesive, a chain length generally above 100 is often required if the polymer is to be used as an elastomer or plastic. 

---