EPDM, additives

Evidence of chemical interaction between the mbbers and compatibUizers was demonstrated by extracting the blends with chloroform at room temperamre and examining both soluble and insoluble fractions with Fourier transform infrared (ETIR) spectrometry. The weight of the insoluble fraction of the compatibilized melt blend was more than that in the uncompatibilized blend indicating the formation of (EP-g-MA)-g-CR due to reaction between MA and allylic chlorine of CR. The compounds containing epoxidized EPDM additive were examined by both optical and... 

A typical example of the effect of EPDM addition on the mechanical properties of PP can be seen in the work of DA Silva and Coutinho (4). They described the effect of EPDM amount and also processing condition on the mechanical properties of PP/EPDM blends. As EPDM contents increases, the impact strength of PP/EPDM blends increases but the tensile strength and Young s modulus decrease and the elongation at break increases. Figure 14.1, for instance, illustrates the effect of EPDM contents on the Young s modulus of PP. 

Neutralization of sulfo-EPDM Addition of excess solution of metal acetate in water/methanol solvent Comonomer Ethyhdene norbomene... 

EPDM-Derived Ionomers. Another type of ionomer containing sulfonate, as opposed to carboxyl anions, has been obtained by sulfonating ethylene—propjlene—diene (EPDM) mbbers (59,60). Due to the strength of the cross-link, these polymers are not inherently melt-processible, but the addition of other metal salts such as zinc stearate introduces thermoplastic behavior (61,62). These interesting polymers are classified as thermoplastic elastomers (see ELASTOLffiRS,SYNTHETIC-THERMOPLASTICELASTOLffiRS). 

The use of TAG as a curing agent continues to grow for polyolefins and olefin copolymer plastics and mbbers. Examples include polyethylene (109), chlorosulfonated polyethylene (110), polypropylene (111), ethylene—vinyl acetate (112), ethylene—propylene copolymer (113), acrylonitrile copolymers (114), and methylstyrene polymers (115). In ethylene—propylene copolymer mbber compositions. TAG has been used for injection molding of fenders (116). Unsaturated elastomers, such as EPDM, cross link with TAG by hydrogen abstraction and addition to double bonds in the presence of peroxyketal catalysts (117) (see Elastol rs, synthetic). 

There are five North American manufacturers of EPDM Unhoyal Chemical, Exxon, DuPont, DSM, and Bayer. In addition. Union Carbide and Dow are manufacturing the new gas-phase polymers. A new joint agreement between Dow and DuPont will offer these two companies some competitive advantages in this market. Trade names of commercial ethylene—propylene polymers include Bayer s Epsyn, Exxon s Vistalon, DuPont s Nordel, and Unhoyal s Royalene. 

Butyl polymers are about 8—10 times more resistant to air permeabiUty compared to natural mbber and have excellent resistance to heat and steam or water. This accounts for its use in gaskets and diaphragms for hot water and steam service. In addition, butyl mbber can be compounded to have low residence properties and has found use in high damping mounts for engines, motors, and similar devices. Halobutyl mbbers can be blended with natural mbber, polychloroprene, and EPDM to greatiy enhance theh permeabiUty resistance. 

Catalyst residues, particularly vanadium and aluminum, have to be removed as soluble salts in a water-washing and decanting operation. Vanadium residues in the finished product are kept to a few ppm. If oil-extended EPDM is the product, a metered flow of oil is added at this point. In addition, antioxidant, typically of the hindered phenol type, is added at this point. 

The best oxidation inhibitors are not usually the best antio2onants (qv). A disubstituted i ra-phenylenediamine such as AJ-isopropyl-AT-phenyl- -phenylenediamine is often selected for that purpose. -Phenylenediamine derivatives iaterfere with cure chemistry and scorchiness, and can stain objects ia contact with the vulcani2ate (114). On balance, /V-(1,3-dimethy1buty1)-/V-phenyl- -phenylenediamine and phenyl /to1y1- -pheny1enediamines have the best combination of properties. They are less scorchy and provide excellent o2one and heat resistance. Additional protection is gained ia blends with a small amount of EPDM mbber (126). 

A manufacturer considering using a thermoplastic elastomer would probably first consider one of the thermoplastic polyolefin rubbers or TPOs, since these tend to have the lowest raw polymer price. These are mainly based on blends of polypropylene and an ethylene-propylene rubber (either EPM or EPDM) although some of the polypropylene may be replaeed by polyethylene. A wide range of blends are possible which may also contain some filler, oil and flame retardant in addition to the polymers. The blends are usually subject to dynamic vulcanisation as described in Section 11.9.1. 

The effect of ionomer concentration on the mechanical properties of PP-EPDM blends is given Table 9. It is seen that the tensile strength and modulus show a maximum at 5 wt% of both ionomer A and B, thereafter, it decreases at higher ionomer loading. The properties are higher for ternary blends containing ionomer B than these containing ionomer A. On the other hand, addition... 

Proper selection of plastic matrix fire retardants and property enhancers offers acceptable combinations of impact properties and heat-distortion temperature (HDT) values for fire retardant plastics. This can be demonstrated by fire retardant styrenics. Fire retardant enhancers have special interest as property enhancers for example the addition of a highly flammable material such as ethylene propylene diene terpolyer (EPDM), dramatically improves the bromine efficiency of octabromodiphenyl oxide in ABS by increasing char-forming without changing the Sb-Br reaction. 

This development was technologically successful and E-plastomers are widely recognized to be very effective impact modifiers for iPP. In initial experiments, binary blends of iPP were compounded with EPDM, E-plastomers, or SEES as the elastomeric phase. In comparison to the known modifiers, such as EPDM or SEES, the binary blends with E-plastomers have properties which strongly depend on the amount and the identity of the E-plastomer. Thus, the addition of... 

Table 11.14 gives critical stress, critical strain, and critical stored energy of NR-EPDM blends for initiation of ozone cracking. All the properties show an increase on addition of TOR, especially the critical stored energy. Stored energy is a strong indicator of ozone resistance and shows an increase by about 80% on addition of 20 parts of TOR to the compound. This was confirmed by SEM pictures of surface ozone cracks and the results of dynamic mechanical moduli and tan d measurement. 

Kumar et al. have studied the miUing behavior of brominated isobutylene-co-p-methyl styrene (BIMS) and its blends with EPDM [40]. Using the theoretical model of Tokita, they have tried to optimize the rmU parameters. They measured the critical nip-gap at which a front-to-back roll transition takes place. They concluded that addition of different fillers reduced the critical nip-gap for BIMS as compared to the gum polymer. The critical nip-gap is lower for systems containing... 

In Table 13.1 an overview of the resistance against ASTM 3 oil (70 h at 150°C) and fuel C (70 h at 150°C) for a large number of industrially applied mbbers is presented [6] (additional data are taken from reference [7]). Rubbers such as EPDM, polyisoprene (IR), butyl mbber (HR), NR, and BR have a high oil swell, due to their hydrocarbon stmcture, which is very similar to the stmcture of the oil itself. Rubbers such as CR, NBR, HNBR, and ECO have a much lower oil swell, because the polarity of these mbbers is higher. The oil resistance can also be improved by lowering... 

FIGURE 30.11 Sampling along a compounding line for a filled ethylene-propylene-diene monomer (EPDM) compound curatives addition on open mill. 

FIGURE 30.18 Ethylene-propylene-diene monomer (EPDM) compounding quarter cycle integration ratio versus strain, at 0.5 and 1.0 Hz samples at position TR (at dump), EM (after curatives addition), and AG (after cooling). 

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