Rubber reinforced polymer systems

ABS and HIPS. The yield stress vs. W/t curves of ABS and HIPS are very similar. They are somewhat surprising because the yield stresses reach their respective maximum values near the W/t (or W/b) where plane strain predominates. This behavior is not predicted by either the von Mises-type or the Tresca-type yield criteria. This also appears to be typical of grafted-rubber reinforced polymer systems. A plausible explanation is that the rubber particles have created stress concentrations and constraints in such a way that even in very narrow specimens plane strain (or some stress state approaching it) already exists around these particles. Consequently, when plane strain is imposed on the specimen as a whole, these local stress state are not significantly affected. This may account for the similarity in the appearance of fracture surface electron micrographs (Figures 13a, 13b, 14a, and 14b), but the yield stress variation is still unexplained. 

Buca . [Engelhard] Hydrous aluminum silicate reinforcing extender for rubber and polymer systems. 

This year s U.S. production of thermoplastics, thermosets, and synthetic rubber is expected to be 29 billion pounds. About 80% of this is based on only a few common monomers. To improve performance, the polymer industry rarely changes to a new, probably more expensive polymer, but instead it shifts from mere homopolymers to copolymers, polyblends, or composites. These three types of multicomponent polymer systems are closely inter-related. They are intended to toughen brittle polymers with elastomers, to reinforce rubbers with active fillers, or to strengthen or stiffen plastics with fibers or minerals. 

Reinforcement of SBR with carbon black leads to vulcani2ates which resemble those of natural rubber, and the two products are interchangeable in most applications. As with natural rubber, accelerated sulfur systems consisting of sulfur and an activator comprising a metal oxide (usually zinc oxide) and a fatty acid (commonly stearic acid) are used. A conventional curing system for SBR consists of 2.0 parts sulfur, 5.0 parts zinc oxide, 2.0 parts stearic acid, and 1.0 part N-r-butylbenzothiazole-2-sulfenide (TBBS) per 100 parts polymers. 

In most of the two-component systems discussed so far, such as rubber-reinforced polyblends, the density or specific volume is approximately an average of the values for each component. There may be some exceptions to this generalization for example, if the smaller component fills free volume available in the major phase (Chander, 1971 Harmer, 1962 Huang and Kanitz, 1969). A similar but more important phenomenon exists when the volume available for filling by a monomer comprises not only free volume elements, but also gross pores, which may range in size from tens of angstroms to the order of micrometers or more. Examples of matrices may include partially sintered polymers, ceramics or metals, cement, concrete, minerals and rocks, paper, and wood (American Chemical Society, 1973). Clearly such systems tend to be complex even the matrix itself is often a multiphase material. 

It has now been shown that recent studies of relaxation, sorptive, and diffusive behavior in many filled polymer systems amply confirm earlier observations of deviations from values predicted by simple additivity (Kumins, 1965). Such effects are not confined to high-surface-area fillers such as certain carbon blacks and fillers (typical reinforcing fillers for rubber) they are also observed frequently with low-surface-area fillers, such as pigments and even glass beads with average diameters in the range of tens of micrometers. 

Uses Crosslinking reagent, adhesion promoter for fiber coatings reactive diluent with other polymers, in solv.-free coating systems, laminating resins, fiber-reinforced composites, coating of tech, polyester and Aramide fibers (as textile reinforcement in tires, conveyor belts) in the fiber, rubber and polymer industry Trade Name Synonyms GE 100 [Raschig]... 

Clay reinforcement has already been used in various polymer systems including polyamide, polypropylene, polystyrene and polycarbonate. However, the major challenges in using clay reinforcement in natural rubber are its nonpolar nature, the conventional processing methods used, such as a two-roll mill, and the high molecular weight of natural rubber polymeric chains. 

High-impact rubber-reinforced glassy polymer systems may be divided into two groups [45,46] ... 

Filled polymer systems of industrial importance, e.g., filled rubber compounds, filled thermoplastics are thus meso or microcomposites, possibly with a structuration (of the dispersed phase) at the nano or meso scale. Whilst no sizeable commercial application yet exist for nanocomposites rubbers or thermoplastics (to the author s knowledge), considerable research has been made since 1984 with so-called ex-foliated layered silicate "nano-clays." Exfoliation means that individual clay sheets, of around 1 nm thickness, have been separated and adequately dispersed in the matrix. Some reinforcement has indeed been demonstrated with such exfoliated nanoparticles but, generally with very specific rubber systems and/or at a cost of preparation that is hardly compatible with reasonable chances of commercialization. 

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