Fillers rubber particles

Transition from liquid behavior to solid behavior has been reported with fine particle suspensions with increased filler content in both Newtonian and non-Newtonian liquids. Industrially important classes are rubber-modified polymer melts (small rubber particles embedded in a polymer melt), e.g. ABS (acrylo-nitrile-butadiene-styrene) or HIPS (high-impact polystyrene) and fiber-reinforced polymers. Another interesting suspension is present in plasticized polyvinylchloride (PVC) at low temperatures, when suspended PVC particles are formed in the melt [96], The transition becomes evident in the following... 

The emphasis is on commercial materials and formulations. The reason is that commercial materials are rarely pure materials. A pure homopolymer is a rare species in the real-world materials. To arrive at the desired material s properties, either a copolymer is used, sometimes a blend or a dispersion, or additives or filler materials including rubber particles, carbon black or fibres of various type and make may be added, and are thus commonplace in commercial products. This implies a more complex constitution and morphology than expected for pure polymers. However, obviously, the methods described herein can be applied to pure, unmodified, polymers as well. 

Transparency. Some applications of plastics require transparency. Amorphous plastics should be able to transmit light. Some factors which prevent transparency include unsatura-tion/light absorption, crystallinity, fillers and reinforcing fibers, and use of rubber particles to increase impact strength. The plastics most often used for their transparency are poly(4-methylpentene-l) (TPX), poly(methyl methacrylate) (almost equal to glass), cellulose acetate, propionate, and butyrate, polycarbonate, and polysulfones (slightly yellow). As a research challenge, it is quite possible that fillers and rubber particles could... 

The characteristic time ro=(q/E0) represents the effects of modulus as well as hysteresis arising from the rubber and/or the filler-rubber interfacial slippage. The inverse particle diameter, 1/d, is proportional to the specific surface area, S, and (dl4 /zg)u being the so-called junction shape factor. The proportionality to h 1A is almost identical to the correlation found by Wolff et al. [89] between tanS and the reciprocal of interaggregate distance, Saa 1. Combined with Eq. (51), Eq. (54) can be written as... 

Rubber particles of various origins are used in friction materials to provide friction and wear improvement, noise damping, and as a cost-reducing filler. Powders made from tire peel and other recycled rubber products and partially cross-linked acrylonitrile powders are the most widely used products in friction materials. 

Names rubber particles, rubber filler, ground rubber... 

The way in which a filler is incorporated has an effect on fracture resistance. Figure 8.33 shows a schematic representation of the microstructure of fillers. The rubber particles are generalized as rubber particles added in a toughening process (a), rubber or polymer coating in core-shell microstructure, bound polymer, or surface coating (b). 

Figure 8.33. Schematic represeiitatioii of three representations of microstructure of fillers (x) and rubber particles (O) in polymer matrix. [Adapted, by permission, from Yu Long, Shanks R A, J. Appl. Polym. Sci., 61, No.ll, 1996, 1877-85.]...

Filled epoxy resins wastes can be ground and used as a filler for various materials. Recycled rubber particles are sometimes used for toughening of epoxy... 

Typical fillers wood flour, glass fiber, carbon fiber, mica, wollastonite, mineral wool, talc, magnesium hydroxide, graphite, molybdenum sulfide, carbon black, cashew shell particles, alumina, chromium oxide, brass and copper powder, iron particles, steel fiber, ceramic powder, rubber particles, aramid, wollastonite, cellulosic fiber, lignin... 

Typical fillers calcium carbonate, calcium sulfate, silica, organic fibers, graphite, mica, bentonites, sand, aluminum hydroxide, sepiolite, rubber particles... 

Special considerations sepiolite treatment below 550°C does not alter the properties which modify the rheological properties of adhesives filler presence may affect adliesion (see Figure 8.54) rubber particles are hygroscopic and can absorb 1.4% moisture with the rate of 0.01% per minute (similar to carbon black) " ... 

Polymers that have been toughened by incorporating another phase are classic examples of multiphase materials. For historic reasons, they are usually referred to as blends if toughened by rubber particles, and as composites if toughened by rigid particles ( fillers ) or by voids. Chapters 19 and 20 discuss multiphase materials in much greater detail in a broad context. 

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