Ethylene propylene copolymer, use

The composition dependence of Tm is investigated for RIS models of atactic PP and random ethylene - propylene copolymers using a modified Flory s equation. 

Present-day Ziegler-Natta catalysts are supremely suitable for the production of linear polyethylene and of highly isotactic polypropylene. They are also used to produce the softer ethylene-propylene copolymers, used for packaging and related purposes. Due to the presence of distinct catalyst sites in typical Ziegler-Natta catalysts, these copolymers suffer from non-uniformity however, and copolymers which contain increased amounts of higher ot-olefins, desirable for certain applications, cannot easily be made with these catalysts. 

More recently a method for the mathematical processing of pyrograms of an ethylene-propylene copolymer using factorial analysis and multiple regression analysis was described [232]. This method permits the rapid determination of a peak or a group of peaks for calculating the content of the degradation products of interest. 

Sim, C. X., van der Mee, A. ]., Goossens, J. G. R, and van Duin, M. 2006. Thermoreversible cross-linking of maleated ethylene/ propylene copolymers using hydrogen-bonding and ionic interactions. Macromolecules 39 3441-3449. 

Sworen, J.C., Smith, J.A., Wagener, K.B., Baugh, L.S., Rucker, S.P., Modeling random methyl branching in ethylene/propylene copolymers using metathesis chemistry synthesis and thermal behavior, J. Am. Chem. Soc. 2003, 125 2228-2240. 

Paxson and Randall [38] in their method use the reference chemical shift data obtained on a predominantly isotactic polypropylene and on an ethylene-propylene copolymer (97% ethylene). They concluded that the three ethylene-propylene copolymers used in their study (97-99% propylene) contained principally isolated ethylene-ethylene linkages. Knowing the structure of their three ethylene-propylene copolymers, they used the C-NMR relative intensities to determine ethylene-propylene contents and thereby establish reference copolymers for the faster IR method involving measurements at 732 cm (13.66 pm). After a detailed analysis of resonances Paxson and Randall [38] concluded that methine resonances 4 and 5 (Table 10.1) gave the best quantitative results to determine the comonomers composition. The composition of the ethylene-propylene copolymers was determined by peak heights using the methine resonances only. In no instance was there any evidence for an inclusion of consecutive ethylene units. Thus, composition data from C-NMR could now be used to establish an IR method based on a correlation with the 732 (13.66 pm) band which is attributed to a rocking mode, r, of the methylene... 

Chem. Descrip. Isododecane, butylene/ethylene/propylene copolymer Uses Film-former, pigment dispersant, base for styling prods., body lotions, facial moisturizers, face treatments, makeup foundations, lipsticks, mascara, colored cosmetics Properties Gel... 

Rohm GmbH [II] have disclosed the synthesis of methacrylate-based VI improvers. The majority of the products are reported to be multifunctional in nature. Peimewiss et al. at Rohm GmbH [11] reported the copolymerization of C12-18 alkyl methacrylates in the presence of ethylene-propylene copolymer, using CvHu-CCOj-OOBu-terr. as an initiator. After treatment with V-vinyl-pyrrolidone and V-vinyl-imidazone, the resulting product was reported to be a good dispersant and VI improver. 

Many cellular plastics that have not reached significant commercial use have been introduced or their manufacture described in Hterature. Examples of such polymers are chlorinated or chlorosulfonated polyethylene, a copolymer of vinyUdene fluoride and hexafluoropropylene, polyamides (4), polytetrafluoroethylene (5), styrene—acrylonitrile copolymers (6,7), polyimides (8), and ethylene—propylene copolymers (9). 

Organic peroxides are used in the polymer industry as thermal sources of free radicals. They are used primarily to initiate the polymerisation and copolymerisation of vinyl and diene monomers, eg, ethylene, vinyl chloride, styrene, acryUc acid and esters, methacrylic acid and esters, vinyl acetate, acrylonitrile, and butadiene (see Initiators). They ate also used to cute or cross-link resins, eg, unsaturated polyester—styrene blends, thermoplastics such as polyethylene, elastomers such as ethylene—propylene copolymers and terpolymers and ethylene—vinyl acetate copolymer, and mbbets such as siUcone mbbet and styrene-butadiene mbbet. 

Combination techniques such as microscopy—ftir and pyrolysis—ir have helped solve some particularly difficult separations and complex identifications. Microscopy—ftir has been used to determine the composition of copolymer fibers (22) polyacrylonitrile, methyl acrylate, and a dye-receptive organic sulfonate trimer have been identified in acryHc fiber. Both normal and grazing angle modes can be used to identify components (23). Pyrolysis—ir has been used to study polymer decomposition (24) and to determine the degree of cross-linking of sulfonated divinylbenzene—styrene copolymer (25) and ethylene or propylene levels and ratios in ethylene—propylene copolymers (26). 

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). 

Two random copolymers of this type are of importance, ethylene-propylene copolymers and ethylene-but-l-ene copolymers. The use and properties of polypropylene containing a small quantity of ethylene in stereoblocks within the molecule has already been discussed. Although referred to commercially as ethylene-propylene copolymers these materials are essentially slightly modified polypropylene. The random ethylene-propylene polymers are rubbery and are discussed further in Section 11.9. 

One component obeys the Bemoullian model the other two obey the enantiomorphic- site model. Similarly, the NMR data of fractionated copolymers can be used to demonstrate the presence of multiple components in the copolymers. An example is shown of ethylene-propylene copolymers where the NMR/fractionation data are used to show the presence of two or three catalytic sites. 

As an example of the use of MIXCO.TRIAD, an analysis of comonomer triad distribution of several ethylene-propylene copolymer samples will be delineated. The theoretical triad Intensities corresponding to the 2-state B/B and 3-state B/B/B mixture models are given In Table VI. Abls, et al (19) had earlier published the HMR triad data on ethylene-propylene samples made through continuous polymerization with heterogeneous titanium catalysts. The data can be readily fitted to the two-state B/B model. The results for samples 2 and 5 are shown In Table VII. The mean deviation (R) between the observed and the calculated Intensities Is less than 1% absolute, and certainly less than the experimental error In the HMR Intensity determination. 

The HMR/fractionatlon approach gives very good results When applied to ethylene-propylene copolymer fractions reported by Abls, et. al. (19) These authors extracted sample 5 (In Table VII) with hexane to get soluble and Insoluble fractions (5a and 5b), and with ether to get soluble and insoluble fractions (5c and 5d). The hexane set (5a and 5b) and the ether set (5c and 5d) can be separately analyzed by the HIXCO.TRIADX program. The results are shown In Table VIII. In the 2-state (B/B) model, we have 4 parameters and 12 values to fit to HMR data of pairwise fractions. In the 3-state (B/B/B) model, we have 7 parameters and 12 values to fit. Thus, the use of pairwise fractions Is absolutely essential for 3-state analysis. 

An oil-based drilling mud can be viscosified with maleated ethylene-propylene elastomers [919]. The elastomers are ethylene-propylene copolymers or ethylene-propylene-diene terpolymers. The maleated elastomers are far more effective oil mud viscosifiers than the organophilic clays used. On the other hand, specific organophilic clays can provide a drilling fluid composition less sensitive to high temperatures [491]. 

The isoprene units in the copolymer impart the ability to crosslink the product. Polystyrene is far too rigid to be used as an elastomer but styrene copolymers with 1,3-butadiene (SBR rubber) are quite flexible and rubbery. Polyethylene is a crystalline plastic while ethylene-propylene copolymers and terpolymers of ethylene, propylene and diene (e.g., dicyclopentadiene, hexa-1,4-diene, 2-ethylidenenorborn-5-ene) are elastomers (EPR and EPDM rubbers). Nitrile or NBR rubber is a copolymer of acrylonitrile and 1,3-butadiene. Vinylidene fluoride-chlorotrifluoroethylene and olefin-acrylic ester copolymers and 1,3-butadiene-styrene-vinyl pyridine terpolymer are examples of specialty elastomers. 

Since the excellent work of Moore and Watson (6, who cross-linked natural rubber with t-butylperoxide, most workers have assumed that physical cross-links contribute to the equilibrium elastic properties of cross-linked elastomers. This idea seems to be fully confirmed in work by Graessley and co-workers who used the Langley method on radiation cross-linked polybutadiene (.7) and ethylene-propylene copolymer (8) to study trapped entanglements. Two-network results on 1,2-polybutadiene (9.10) also indicate that the equilibrium elastic contribution from chain entangling at high degrees of cross-linking is quantitatively equal to the pseudoequilibrium rubber plateau modulus (1 1.) of the uncross-linked polymer. 

Over the last decade, selected papers1114 have examined the deposition of fluoropolymers, using RF magnetron sputtering. All of these papers have examined the deposition of PTFE, with some of them2314 also studying the deposition of polyimide (PI) films. This chapter extends these studies and will report on the sputter deposition behavior of PTFE (polytetrafluoroethylene), PVDF (polyvinylidenefluoride), and FEP (fluorinated ethylene propylene copolymer) films. 

Initiators such as BPO are used not only for the initiation of chain reaction polymerization, but also for the curing of polyesters and ethylene-propylene copolymers, and for the grafting of styrene on elastomeric polymer chains. 

PVC, another widely used polymer for wire and cable insulation, crosslinks under irradiation in an inert atmosphere. When irradiated in air, scission predominates.To make cross-linking dominant, multifunctional monomers, such as trifunctional acrylates and methacrylates, must be added. Fluoropolymers, such as copol5miers of ethylene and tetrafluoroethylene (ETFE), or polyvinylidene fluoride (PVDF) and polyvinyl fluoride (PVF), are widely used in wire and cable insulations. They are relatively easy to process and have excellent chemical and thermal resistance, but tend to creep, crack, and possess low mechanical stress at temperatures near their melting points. Radiation has been found to improve their mechanical properties and crack resistance. Ethylene propylene rubber (EPR) has also been used for wire and cable insulation. When blended with thermoplastic polyefins, such as low density polyethylene (LDPE), its processibility improves significantly. The typical addition of LDPE is 10%. Ethylene propylene copolymers and terpolymers with high PE content can be cross-linked by irradiation. ... 

---