Polymer ethylene/propylene/diene, EPDM

Ozonc-rcsjstant elastomers which have no unsaturation are an exceUent choice when their physical properties suit the appHcation, for example, polyacrylates, polysulfides, siHcones, polyesters, and chlorosulfonated polyethylene (38). Such polymers are also used where high ozone concentrations are encountered. Elastomers with pendant, but not backbone, unsaturation are likewise ozone-resistant. Elastomers of this type are the ethylene—propylene—diene (EPDM) mbbers, which possess a weathering resistance that is not dependent on environmentally sensitive stabilizers. Other elastomers, such as butyl mbber (HR) with low double-bond content, are fairly resistant to ozone. As unsaturation increases, ozone resistance decreases. Chloroprene mbber (CR) is also quite ozone-resistant. 

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

NMR results are quantitative. Analysis of a 13C or H spectrum would reveal the different types of functionalities, as well as their contents in the sample. For example, Figure 9 shows the H NMR spectrum of the diene (ENB) in an EPDM polymer (ethylene-propylene diene monomer). 

Parikh, D. R. Edmondson, M. S. Smith, B. W. Winter, J. M. Castille, M. J. Magee, J. M. Patel, R. M. Karajala, T. P. Structure and Properties of Single-site Constrained Geometry Ethylene-Propylene-Diene (EPDM) Elastomers. In Metallocene-catalyzed Polymers -Materials, Properties, Processing Markets, Benedikt, G. M., Goodall, B. L., Eds. Plastics Design Library New York, 1998 p 113. 

Research efforts on filled polymer blends have been more focused on nanopartide-filled systems [42, 43]. One usual observation is the same as those with microscopic fillers - polar nanofillers localize in more polar phases [44—53]. In cases where both phases are polar or nonpolar, the filler particles have been observed to be expelled from both phases in the blend [54—56]. Selective localization of nano-sized partides has been an interesting topic of research. We discuss some of the results here. Gahleitner et al. [57] observed a preferential localization of clay particles in PA6 droplets in PA6/PP blends. Recall that day, espedally montmorillonite, is highly polar in both its pristine and various organically modified forms [58-62]. Similarly, Wang et al. [63] reported selective localization of clay particles in maleic anhydride grafted ethylene-propylene-diene (EPDM-MA) rubber droplets in poly(trimethylene terephthalate)/EPDM-MA blends. Selective localization of fillers other than clay particles has also been reported. Eor instance, Ou and Li [64] observed that toluene diisocyanate modified titania particles selectively localized in PA6 droplets in PP/ PA6/titania blends. 

Abraham et al. [158] were the first ones to propose saturating commercially available microporous polyolefin separators (e.g., Celgard ) with a solution of lithium salt in a photopolymerizable monomer and a nonvolatile electrolyte solvent. The resulting batteries exhibited low discharge rate capability due to the significant occlusion of the pores with the polymer binder and the low ionic conductivity of this plasticized electrolyte system. Dasgupta and Jacobs [157,168] patented several variants of the process for the fabrication of bonded-electrode lithium-ion batteries, in which a microporous separator and electrode were coated with a liquid electrolyte solution, such as ethylene-propylene-diene (EPDM) copolymer and then bonded under elevated temperature and pressure conditions. This method required that the whole cell assembling process be carried out in scrupulously anhydrous conditions, which make this approach difficult, and expensive. 

The list of polymers known to respond satisfactorily to permanganic etching is now long and continually growing. It consists of linear and branched polyethylene, four isotactic polyolefins (polypropylene, polystyrene, poly(4-methylpentene-l) and poly(butene-l)), related atactic polymers, poly(vinylidene fluoride) (hereafter denoted PVF2), PEEK, and poly(ethylene terephthalate) (PET), together with various copolymers and others such as ethylene propylene rubbers and ethylene-propylene-diene (EPDM) terpolymer. 

Polyolefins, PO. First impact modification of PO, by addition of elastomers, was patented independently by Bayer A.-G. and Standard Oil Co. in 1937. The isotactic polypropylene, PP, was commercialized in 1957, and its first blends (with polyisobutylene, PIB, and polyethylene, PE) were patented in 1958. In 1960, du Pont started manufacturing ethylene-propylene, EPR, and three years later ethylene-propylene-diene, EPDM, copolymers [Gresham and Hunt, I960]. The first patent on impact modification of PP by addition of EPR dates from 1960. Direct reactor blending of PE/PP/EPR resulting in a thermoplastic polyolefin, R-TPO, dates from 1979. The newest (introduced in 1992) single-site metallocene catalysts generate polymers with controlled tacticity, co-monomer sequences, molecular... 

Coordination catalysts are also used to make elastomers, notably ethylene-propylene-diene (EPDM) rubbers [6]. In this case, homogeneous catalysts are preferred to heterogeneous ones because they generally produce polymers with a more uniform distribution of crystallinity. The unreacted double bonds of the dienes are used during rubber crosslinking reactions. Figure 8.4 shows some typical examples of dienes used for the manufacture of EPDM rubbers. 

Gamlin, C.D., Dutta, N.K., Choudhury, N.R. Mechanism and kinetics of the isothermal thermodegradation of ethylene-propylene-diene (EPDM) elastomra. Polym. Degrad. Stab. 80, 525-531 (2003)... 

Ethylene—Propylene Rubber. Ethylene and propjiene copolymerize to produce a wide range of elastomeric and thermoplastic products. Often a third monomer such dicyclopentadiene, hexadiene, or ethylene norbomene is incorporated at 2—12% into the polymer backbone and leads to the designation ethylene—propylene—diene monomer (EPDM) mbber (see Elastomers, synthetic-ethylene-propylene-diene rubber). The third monomer introduces sites of unsaturation that allow vulcanization by conventional sulfur cures. At high levels of third monomer it is possible to achieve cure rates that are equivalent to conventional mbbers such as SBR and PBD. Ethylene—propylene mbber (EPR) requires peroxide vulcanization. 

Ethylene—Propylene (Diene) Rubber. The age-resistant elastomers are based on polymer chains having a very low unsaturation, sufficient for sulfur vulcanization but low enough to reduce oxidative degradation. EPDM can be depicted by the following chain stmcture ... 

FIGURE 11,1 Ultrasonic velocity versus acrylonitrile-butadiene mbber/ethylene-propylene-diene monomer (NBR-EPDM) blend composition (a) no compatibiUzer, (b) with chloro-sulfonated polyethylene (CSM), and (c) with chlorinated polyethylene (CM). (From Pandey, K.N., Setua, D.K., and Mathur, G.N., Polym. Eng. Set, 45, 1265, 2005.)... 

FIGURE 12.7 Monsanto rheometric curves of ethylene-propylene-diene monomer (EPDM) rubber-melamine fiber composites [64]. A, gum compound B, compound containing 30 phr melamine fiber but no dry bonding system and C, compound containing both dry bonding system and 30 phr melamine fiber. (From Rajeev, R.S., Bhowmick, A.K., De, S.K., Kao, G.J.P., and Bandyopadhyay, S., Polym. Compos., 23, 574, 2002. With permission.)... 

Radiation Treatment NVP, 2-hydroxyethylmethacrylate (HEMA), and acrylamide (AAm) have been grafted to the surface of ethylene-propylene-diene monomer (EPDM) rubber vulcanizates using the radiation method (from a Co 7 source) to alter surface properties such as wettability and therefore biocompatibility [197]. Poncin-Epaillard et al. [198] have reported the modification of isotactic PP surface by EB and grafting of AA onto the activated polymer. Radiation-induced grafting of acrylamide onto PE is very important... 

FIGURE 31.7 Representative plots showing the variation of tan 5 with temperature for the control ethylene-propylene-diene monomer (EPDM) irradiated to various doses. (From Sen Majumder, P. and Bhowmick, A.K., J. Appl Polym. Sci., 77, 323, 2000. With permission.)... 

FIGURE 38.6 Morphology of (a) ethylene-propylene-diene monomer (EPDM)-poly(ethylene-co-acrylic acid) blend (b) EPDM-poly(ethylene-co-acrylic acid)-ground rubber tire (GRT) blend. (Reprinted from Naskar, A.K., Bhowmick, A.K., and De, S.K., Polym. Eng. Sci., 41, 1087, 2001. With permission from Wiley InterScience.)... 

Ethylene-propylene-diene terpolymers (EPDM), with their inherent complexity in structural parameters, owe their tensile properties to specific structures dictated by polymerization conditions, among which the controlling factor is the catalyst used in preparing the polymers. However, no detailed studies on correlation between tensile properties and EPDM structures have been published (l,2). An unusual vulcanization behavior of EPDMs prepared with vanadium carboxylates (typified by Vr g, carboxylate of mixed acids of Ccj-Cq) has been recently reported Q). This EPDM attains target tensile properties in 18 and 12 minutes at vulcanization temperatures of 150 and l60°C respectively, while for EPDMs prepared with V0Cl -Et3Al2Cl or V(acac) -Et2AlCl, about 50 and 0 minutes are usually required at the respective vulcanization temperatures, all with dieyclopentadiene (DCPD) as the third monomer and with the same vulcanization recipe. This observation prompted us to inquire into the inherent structural factors... 

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