Ethylene-propylene diene modified

Other rubber systems have been commercially successful. Styrene block copolymers yield a HIPS product with a small particle size and provide high gloss. A mixed rubber system consisting of styrene-butadiene block rubber and/or ethylene-propylene diene modified (EPDM) rubber can be blended with the polybutadiene to form bimodal rubber particle size distribution for a... 

EPDM Ethylene-propylene-diene modified rubber... 

The most popular types for bioprocessing plants are the diaphragm and ball valves types. The latter are more robust but contain crevices making sterilisation more difficult. Barnsleystated a preference for diaphragm valves since they are reasonably crevice free the material EPDM (ethylene propylene diene modified) was the preferred diaphragm material. 

Initial materials of this super-tough type were blends of nylon 66 with an ionomer resin (see Chapter 11). More recent materials are understood to be blends of nylon 66 with a modified ethylene-propylene-diene terpolymer rubber (EPDM rubber—also see Chapter 11). One such modification involves treatment of the rubber with maleic anhydride, this reacting by a Diels—Alder or other... 

FIGURE 31.8 Change in the coefficient of friction of modified dicumyl peroxide/ethylene-propylene-diene monomer (DCPD/EPDM) with the concentration of trimethylolpropane triacrylate (TMPTA) at a fixed irradiation dose of 100 kGy. (G) Surface modified with 100 kGy, (A) Bulk modified with 100 kGy dose, ( ) Control EPDM rubber. (Erom Sen Majumder, P. and Bhowmick, A.K., Wear, 221, 15, 1998. With permission.)... 

Besides MMBS, also related copolymers, such as methyl meth-acrylate/acrylonitrile/butadiene/styrene and acrylonitrile/ethylene/ propylene/diene/styrene are impact modifiers for PC compositions (16). 

Bhowmick and co-workers [168] investigated the bulk and surface modification of ethylene propylene diene monomer (EPDM) rubber and fluoro-elastomer by electron beam irradiation. The structure of the modified elastomers was analysed with the help of IR spectroscopy and XPS. The gel content, surface energy, friction coefficient and dynamic mechanical properties of bulk modified fluoro-elastomers and the surface-modified EPDMs were also measured. The resultant properties of the modified EPDM were correlated with the structural alterations. 

Many other reports have demonstrated the smoke suppressing tendencies of hydrated fillers in various polymers including ethylene-propylene-diene elastomers,43 PP,38 polystyrene,49 modified polyphenylene oxide, polybutylene terephthalate, and ABS.37 In addition to suppressing smoke generation, a delay in the onset of smoke evolution is also achievable.25 Figure 7.5 illustrates smoke reductions obtained in PP. 

Esterified polystyrene-co-maleic anhydride Polyethylene-co-propylene Poly(ethylene-co-propylene diene-modified) Poly(ethylene-co-propylene-co-olefin diene-modified) Hydrogenated polystyrene-co-butadiene Hydrogenated polystyrene-co-isoprene Hydrogenated polyisoprene. 

Composition (type of polymeric components). The base polymer (which is to be modified) may be an amorphous polymer [e.g., polystyrene (PS), styrene-acrylonitrile copolymer, polycarbonate, or poly(vinyl chloride)], a semicrystalline polymer [e.g., polyamide (PA) or polypropylene (PP)], or a thermoset resin (e.g., epoxy resin). The modifier may be a rubber-like elastomer (e.g., polybutadiene, ethylene-vinyl acetate copolymer, ethylene-propylene copolymer, or ethylene-propylene-diene copolymer), a core-shell modifier, or another polymer. Even smaller amounts of a compatibilizer, such as a copolymer, are sometimes added as a third component to control the morphology. 

Recent findings indicated that this drawback can be overcome by using particular reinforcing agents, i.e. graft copolymers obtained by modifying saturated or low-unsaturated elastomers such as ethylene-propylene (EP) or ethylene-propylene-diene monomer (EPDM) rubbers and acrylic elastomers (9-16). 

Blends of PET/HDPE have been treated previously in the literature [157, 158]. These are immiscible, but the addition of compatibilizers improves the mechanical properties of the blend, such as styrene-ethylene/butylene-styrene (SEBS) and ethylene propylene diene monomer (EPDM) [157], MAH [158], Poly(ethylene-stat-glycidyl metha-crylate)-graft-poly(acrilonitrile-stat-styrene) (EGMA), poly (ethylene acrylic acid), and maleated copolymers of SEBS, HDPE, ethylene-propylene copolymer (EP). The addition of compatibilizers modifies the rheological properties of blends of PET with HDPE, in such a way that increases in viscosity are observed as the component interactions augment. Changes in crystallization of PET were evaluated in blends with Polyphenylene sulfide (PPS), PMMA, HDPE aromatic polyamides, and copolyesters [159]. 

A significant development is the appearance of supertough nylon plastics, which are blends in nylon-6,6 with other resins, such as an ionomer resin used in the initial grades or a modified ethylene-propylene-diene terpolymer rubber (EPDM rubber) used in later grades. 

As mentioned extensively, PPE is not mainly used as such, but in polymeric blends and copolymers to faciUtate the fabrication. Some of these copolymers act also as impact modifiers for example, block copolymers built from styrene, ethylene, butylene, and propylene. Naturally, the impact can be improved by using high impact poly(styrene) (HIPS) instead of ordinary PS in blends. Other impact modifiers include rubbery materials, such as poly(octenylene), and ethylene propylene diene monomer rubber. 

A process has been developed for electroplating a PPA resin, modified with ethylene propylene diene monomer rubber, ethylene-propylene rubber, and styrene-butadiene rubber. As etching solution, chromic acid is used. However, it has been found that the concentration of Cr + is crucial for the success of the method. The concentration of Cr + is in the range of 50-55 gU Low levels of Cr + result in poor adhesion of the final metal plating, while high levels of Cr + can cause the formation of small blisters in the metal plating. The influence of the process parameters on the peel strength is shown in Table 12.9. 

Papazoglou and Rosenthal[71] produced nylon blends having improved low-temperature properties. Moldable nylon-6 blends with improved low-temperature impact strength and reduced brittleness were prepared by melt blending nylon-6, maleic anhydride-g-ethylene-propylene-diene terpolymer, and rubber modified styrene-maleic anhydride copolymer. The impact property of the rubber-modified nylon composition is given in Table 5. The blend components were melt blended at temperatures between 260 and 310 °C. As a standard, all three components of the blend were simultaneously melt blended (A). Nylon-6 was melted first and then the functionalized terpolymer was melt blended prior to downstream introduction of the rubber modified copolymer (B). Nylon-6 and the functionalized terpolymer were first melt blended and then the rubber modified copolymer was added to the melted mixture at a downstream feed port (C). 

Studies by Ravikumar et al. (2005) show that PTT/ethylene propylene diene monomer (EPDM) blends are irrmriscible, which is supported by an increase in the free volume and constancy in crystallinity of PTT with increasing EPDM content and the use of ethylene propylene monomer grafted maleic anhydride as compatibilizer is found to produce significant improvement in properties by modifying the interface of the blends. 

Most of the earlier efforts have been paid in changing the surface character of clay minerals. Albeit the modified clay minerals are fairly compatible with the polar rubber like acrylonitrile butadiene rubber (NBR), carboxylated nitrile rubber (XNBR), chloroprene rubber (CR), etc., its dispersion in nonpolar rubbers like NR, styrene butadiene rubber (SBR), ethylene propylene diene rubber (EPDM), butadiene rubber (BR), etc. is rather unsatisfactory. Figure 8.3(a) and (b) display the state of dispersion of organomodified... 

EPDM-MA Maleic anhydride-modified ethylene-propylene-diene terpolymer... 

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