Ethylene-propylene rubbers preparation

Greco et al. [50] studied the effect of the reactive compatibilization technique in ethylene propylene rubber-polyamide-6 blends. Binary blends of polyamide-6-ethylene propylene rubber (EPR) and a ternary blend of polyamide-6-EPR-EPR-g-succinic anhydride were prepared by the melt mixing technique, and the influence of the degree of grafting of (EPR-g-SA) on morphology and mechanical properties of the blends was studied. 

CH2CHCH3, propene, the second member of the olefine series of hydrocarbons. It is the monomer used in the preparation of polypropylene and ethylene-propylene rubbers. 

In conjunction with an antioxidant and colorant, Kanae [1] used the Step 3 products as thermoplastic elastomers in automobile moldings. Thermoplastic elastomers having good tensile and impact strength were also prepared by Datta [2] by blending isotactic polypropylene with ethylene-propylene rubber. 

As opposed to the problems associated with the formation of sequential block copolymers, the preparation of relatively random copolymers is much easier and the provision of polyethylenes having a controlled degree of branching by copolymerization with propylene and butene is now a well-established commercial operation. When ethylene and propylene are employed in approximately equal proportions the ethylene-propylene rubbers are obtained. For this purpose strictly random copolymers are desirable, for which soluble vanadium catalysts are often preferred (20). With TiCls-based catalyst the propylene monomer molecule prefers to add to a propylene end unit rather than to an ethylene end unit (and vice versa). This tends to produce nonrandom blocky copolymers. Thus a recent paper by Coover ef al. (21) selects as catalysts formulations which maximize this tendency and achieve the preparation of block copolymers in a TiCl3/AlEt2Cl catalyst system in the presence of butene and propylene together. 

We proved this presumption on blends of PA6 with LDPE and HOPE and on a blend of PE with ethylene-propylene rubber (EPDM). The polyolefin components were functionalized by grafting 1 wt% of itaconic acid (lA) (51,53). Functionalization and preparation of the blends were performed in a static mixer assembled onto the Brabender plastograph (51,73). Grafting with simultaneous cross-linking of PO resulted in a sharp reduction of MFl values and r] of their melt. It can be seen in Table 18.1 that g-POs possess much higher melt viscosities than PA6. The viscosity of LDPE exceeds r] of PA6 by two decimal orders. of PA6 is twice as low as that of... 

Hasegawa, N., Okamoto, H., and Usuki, A., Preparation and properties of ethylene propylene rubber (EPR)-clay nanocomposites based on maleic anhydride-modifled EPR and organophilic clay, J. Appl. Polym. ScL, 93, 758-764 (2004). 

ICP = blends of isotactic propylene homopolymer with ethylene-propylene rubber. These materials are commonly called "impact copolymers," "heterophasic copolymers," or, incorrectly, "block copolymers." These are typically prepared during the polymerization process using a series of reactors. L = low rubber (less than about 15% rubber by weight typically witli an ethylene content of less than about 10%). H = high rubber content blends (greater than about 15% rubber by weight typically with an ethylene content of at least 7%). 

Discuss copolymers of ethylene and propylene. How are they prepared What catalysts are used in the preparations How are ethylene-propylene rubbers crosslinked ... 

Numerous nylon blends prepared by compatibilization or reactive blending are commercially successful. The modifiers fiequenfly utilized in commercial nylon blends include polyolefin, thermoplastic polyolefin, thermoplastic polyunethane, ionomer, elastomer, ethylene-propylene rubber, nitrile mbber, polyftetrafluoroethylene), poly (phenylene ether), poly(ether amide), silicone, glass fiber, and carbon fiber. The nonpolar modifiers such as polyolefin, maleic anhydride or a polar vinyl monomer such as acrylic acid, methaciylic acid and fimiaric acid is fiequently incorporated to introduce reactive sites in nylon. 

Kelusky et al. also indicated that by use of a semi preparative TREF system one could achieve an effective characterization of PE/EPDM terpolymer and PE/polyisobutylene blends. The approach for this type of analysis of blends, in which one of the components was non-crystalline, was to first collect the PIB or EPDM by elution at 30 °C followed by elution of the PE component as an analytical TREF or it could be eluted off, precipitated and recovered for subsequent analysis by SEC or NMR. They point out that the TREF separation of this type of mixture is superior to the usual solvent extraction methods which invariably remove some highly branched or low molecular weight PE in addition to the PIB or EPDM. One would anticipate that such a separation scheme would be effective for other crystalline/amorphous polymer blends such as impact polypropylenes which contain ethylene-propylene rubber. 

Trivinyl aluminium (AlVy,) has been employed as a cationic initiator for the preparation of ,co-dienepolyisobutylene. It also functions as a vinylating agent for tertiary alkyl, and secondary and tertiary allyl chlorides, and has been used, as in Scheme 10, for vinylating chlorinated ethylene-propylene rubber. ... 

Commercial ethylene-propylene rubbers (EPR or EPM ) generally contain about 35 mole % propylene although rubbery properties are shown by copolymers with a propylene content ranging from 30—60 mole %. At the present time, these materials are prepared exclusively by Ziegler-type processes. Generally, true solution processes are preferred in which a soluble catalyst system is used and the polymer remains in solution rather than form a slurry. A common soluble catalyst system is based on vanadium oxychloride/aluminium trihexyl. Catalysts of this type favour the formation of amorphous atactic polymers and lead to narrower molecular weight distributions than solid catalysts. Typically, polymerization is carried out at about 40°C in a solvent such as chlorobenzene or pentane and the polymer is isolated by precipitation with an alcohol. 

Heterophasic propylene-ethylene copolymers (HPEC) consist of crystalline polypropylene (PP) modified by an elastomeric component, typically ethylene-propylene rubber (EPR), and are prepared by polymerization of propylene (P) in the presence of catalysts, and sequential polymerization of a propylene-ethylene mixture with... 

Macromonomers of polymeric dicyclopentadiene and polymeric ethylidene norbomene have been prepared and then terpolymerized with ethylene and propylene. This terpolymer exhibits compatibi-lization of ethylene-propylene rubber and butyl rubber (41). 

MRE composites were prepared according to commonly used methods. Micro- and nanosized iron oxides and carbonyl iron powder were the active fillers of acrylonitrile -butadiene and ethylene - propylene rubber. It was found that micro- and nano- sized iron oxides and carbonyl iron powder improved mechanical properties of elastomers. They also changed their magnetic properties and reinforced the magnetorheological effects of the composites. 

Ethylene propylene mbber-clay nanocomposites were successfully obtained by melt eompounding maleie anhydride modified ethylene propylene rubber (EPR-MA) and organophilie montmorillonite in a twin-screw extruder at 200"C for contents of 2.9 to 8.3wt.% clay (CNs). A range of carbon black and talc filled compoimds were also prepared in the same manner, for comparison purposes. The XRD patterns of the nanocomposites showed no peak for EPR-CNs, which indicated that these nanoeomposites were well delaminated and TEM images confirmed that the layers were exfoliated on the nanometer size seale. ... 

Elastomers. Ethylene—propylene terpolymer (diene monomer) elastomers (EPDM) use a variety of third monomers during polymerization (see Elastomers, ethyiene-propylene-diene rubber). Ethyhdenenorbomene (ENB) is the most important of these monomers and requires dicyclopentadiene as a precursor. ENB is synthesized in a two step preparation, ie, a Diels-Alder reaction of CPD (via cracking of DCPD) with butadiene to yield 5-vinylbicyclo[2.2.1]-hept-2-ene [3048-64-4] (7) where the external double bond is then isomerized catalyticaHy toward the ring yielding 5-ethyhdenebicyclo[2.2.1]-hept-2-ene [16219-75-3] (ENB) (8) (60). 

TPEs from blends of rubber and plastics constitute an important category of TPEs. These can be prepared either by the melt mixing of plastics and rubbers in an internal mixer or by solvent casting from a suitable solvent. The commonly used plastics and rubbers include polypropylene (PP), polyethylene (PE), polystyrene (PS), nylon, ethylene propylene diene monomer rubber (EPDM), natural rubber (NR), butyl rubber, nitrile rubber, etc. TPEs from blends of rubbers and plastics have certain typical advantages over the other TPEs. In this case, the required properties can easily be achieved by the proper selection of rubbers and plastics and by the proper change in their ratios. The overall performance of the resultant TPEs can be improved by changing the phase structure and crystallinity of plastics and also by the proper incorporation of suitable fillers, crosslinkers, and interfacial agents. 

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