Rubber material filler reinforcement

Reinforcement of elastomers by colloidal fillers, like carbon black or silica, plays an important role in the improvement of mechanical properties of high performance rubber materials. The reinforcing potential is mainly attributed to two effects ... 

Carbon black (c.b.) plays an important role in the improvement of the mechanical and/or electrical properties of high performance rubber materials. The reinforcing potential is mainly attributed to two effects (i) the formation of a physically bonded flexible filler network and (ii) strong polymer filler couplings. Both of these effects refer to a high surface activity and specific surface of the filler particles [1-3],... 

By analogy with the works which dealt with cellulose micro crystal-reinforced nanocomposite materials, microcrystals of starch [95] or chitin [96, 97] were used as a reinforcing phase in a polymer matrix. Poly(styrene-co-butyl acrylate) [95,96], poly(e-caprolactone) [96], and natural rubber [97] were reinforced, and again the formation of aggregates or clustering of the fillers within the matrices was considered to account for the improvement in the mechanical properties and thermal stability of the respective composites processed from suspensions in water or suitable organic solvents. 

In view of an illustration of the viscoelastic characteristics of the developed model, simulations of uniaxial stress-strain cycles in the small strain regime have been performed for various pre-strains, as depicted in Fig. 47b. Thereby, the material parameters obtained from the adaptation in Fig. 47a (Table 4, sample type C60) have been used. The dashed lines represent the polymer contributions, which include the pre-strain dependent hydrodynamic amplification of the polymer matrix. It becomes clear that in the small and medium strain regime a pronounced filler-induced hysteresis is predicted, due to the cyclic breakdown and re-aggregation of filler clusters. It can considered to be the main mechanism of energy dissipation of filler reinforced rubbers that appears even in the quasi-static limit. In addition, stress softening is present, also at small strains. It leads to the characteristic decline of the polymer contributions with rising pre-strain (dashed lines in... 

A filled rubber may be regarded at once as a two-phase composite material and as a polymeric network containing giant multifunctional cross-links. Neither concept alone leads to very useful generalizations. The physical properties of a filled vulcanizate do not appear capable of close description in terms of the component filler and rubber properties. On the other hand no degree of cross-linking per se produces effects identical to filler reinforcement. 

For practical applications, rubber material is usually reinforced with fillers. Carbon black is the most common filler. Carbon black is mainly derived fi om aromatic oil in petroleum or from natural gas. Substitution of carbon black (CB) with renewable filler has been investigated in recent years. Recent studies... 

Optically clear filler reinforced silicone rubber was first developed during the mid-nineteen-fifties by Polmanteer and coworkers, working under support of the Air Force Materials Laboratory (AO), for use as high temperature resistant interlayers for high speed aircraft windows. Since that time, other applications for optically clear reinforced silicone rubber have been Identified. 

The arrangement of the blocks is important high-tensile-strength materials, with elastomeric properties similar to a filler-reinforced vulcanizate, are obtained only when the copolymer contains two or more polystyrene (S) blocks per molecule. Thus, copolymers with the structure S.B. or B.S.B. (who B is a polybutadiene block) are as brittle as polystyrene, but S.B.S and S.B.S.B copolymCTS are much tougher. At ambient temperatures these behave like conventional cross-linked rubbers, but they have the additional advantage that their thermal behavior is reproducible. 

Figure 10.14. Characteristic types of Mullins softening in silica-filled rubber vulcanizates. Highly reinforcing fillers give more stress-softening than slightly reinforcing or nonreinforcing materials. (Sellers and Toonder, 1965.)...

TPO materials are defined as compounds (mixtures) of various polyolefin polymers, semicrystalline thermoplastics, and amorphous elastomers. Most TPOs are composed of polypropylene and a copolymer of ethylene and propylene called ethylene—propylene rubber (EPR) [2]. A common rubber of this type is called ethylene propylene diene monomer rubber (EPDM), which has a small amount of a third monomer, a diene (two carbon-carbon double bonds in it). The diene monomer leaves a small amount of unsaturation in the polymer chain that can be used for sulfur cross-linking. Like most TPEs, TPO products are composed of hard and soft segments. TPO compounds include fillers, reinforcements, lubricants, heat stabilizers, antioxidants, UV stabilizers, colorants, and processing aids. They are characterized by high impact strength, low density, and good chemical resistance they are used when durability and reliability are primary concerns. 

This book focuses on the synthesis and characterization of natural rubber composites and nanocomposites, the interaction between reinforcing agents and the rubber matrix and their effect on different properties. The reinforcing effect of traditional fillers in micro range and the effectiveness of these nanofillers are discussed. This book on natural rubber and nano composites comprises of the most recent research activities that will, unquestionably, be a vital reference book for scientists in both the academic and industrial sectors, as well as for individuals who are interested in natural rubber materials. 

This is Volume 2 of Natural Rubber Materials and it covers natural rubber-based composites and nanocomposites in 27 chapters. It focuses on the different types of fillers, the filler matrix reinforcement mechanisms, manufacturing techniques, and applications of natural rubber-based composites and nanocomposites. The first 4 chapters deal with the present state of art and manufacturing methods of natural rubber materials. Two of these chapters explain the theory of reinforcement and the various reinforcing nanofillers in natural rubber. Chapters 5 to 19 detail the natural rubber composites and nanocomposites with various fillers sueh as siliea, glass fibre, metal oxides, carbon black, clay, POSS and natural fibres ete. Chapters 20-26 discuss the major characterisation techniques and the final ehapter covers the applications of natural rubber composites and nanoeomposites. By covering recent developments as well as the future uses of rubber, this volume will be a standard reference for scientists and researchers in the field of polymer chemistry for many years to come. 

Rubber threads are susceptible to oxidative degradation, and high concentrations of antioxidants are added to the mixture to make the high surface area fibers more resistant. Pigments, such as titanium dioxide, are used as fillers or to impart whiteness to the thread. Carbon black reinforcement is used in colored rubber materials. Other agents include accelerators and activators to promote the vulcanization process. With all the additives, a typical high grade rubber thread contains less than 85% elastomer. 

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