Ethylene-propylene copolymers determination

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). 

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. 

Methyl end groups resulting from main-chain scission in ethylene-propylene copolymers have observed by their characteristic 13C NMR resonance and determined quantitatively to give values of G(scission). 

From Mark s RIS model for ethylene-propylene copolymers (J. Chem. Phys. 1972, 57, 2541) it is determined that P(t) = 0.380, P g+) = 0.014, and Pig") = 0.606 in 2,4-dimethylhexane (2,4-DMH). Using this RIS model, furthermore, for all the branched alkanes considered whose isopropyl groups are separated by at least one methylene carbon from the next substituted carbon and the RIS model developed by Asakura et at. (Makromol. Chem, 1976, 177, 1493) for head-to-head polypropylene to treat 2,3-dimethyl pentane, AS s are calculated for a large number of branched alkanes. The agreement between the observed and the calculated nonequivalent 13C NMR chemical shifts is quite good, including the prediction that separation of the isopropyl group from the next substituted carbon by four or more methylene carbons removes the nonequivalence. 

Bench-scale tests were conducted to determine design parameters and operability of Che distillation process for the pilot plant. The column, reboller, and condenser used in the bench-scale system were constructed of fiberglass-reinforced ethylene-chlorotrifluoroethylene. The heat exchangers were spaghetti tube bundles constructed of fluorinated ethylene-propylene copolymer. 

Materials. Ethylene-propylene copolymer, purified by Kumagawa (9) acetone extraction for 180 hours had a composition (determined by infrared) of C2 — 54.5, C3 = 45.5 wt %, and an intrinsic viscosity determined in toluene at 30°C of 1.38 X 10 cc/gram. Poly (vinyl alcohol) was Elvanol 50-42 from du Pont. The vinyl chloride monomer of Monte-catini Edison was 99.99% pure. Initiators used were ... 

A final quantitative example is that of determining the % ethylene in ethylene-propylene copolymers (EPM). The International Institute of Synthetic Rubber Producers (IIRP) Technical/Operating Committee and the American Society for Testing and Materials (ASTM) cooperated to produce an updated standard method [56]. They also produced a set of standards with the ethylene content established by 13C NMR. Those standards were utilised by Parker and Waddell to study the photoacoustic determination of % ethylene [57]. Three of the four infrared band ratios specified by ASTM were measured, 1378/1462, 1378/722, and 1156/722. The fourth one, 1156/4255, was not used since it involves measurements in the near-IR region. Baselines were drawn by the valley-to-valley technique as illustrated in Figure 2.11. 

ASTM Method D3900-95 (2000) Standard Test Methods for Rubber-Raw Determination of Ethylene Units in EPM (Ethylene-Propylene Copolymers) and EPDM (Ethylene-Propylene-Diene Terpolymers). 

Ethylene-propylene copolymer films gave a very broad absorption in the visible region upon electron-pulse irradiation (Fig. 16) [93], It was comprised of at least three species, electrons, excited states, and alkane radical cations. At about 700 nm and 800 nm the contributions from excited states and radical cations, respectively, were largest. The lifetime of the radical cation determined... 

Tosi, C., F. Ciampei,l.i, and A. Valvassori A new spectroscopic method for the determination of the product of reactivity ratios corresponding to ethylene-propylene copolymers. European Polymer J. 4, 107 (1968). 

Since the discovery of olefin polymerization using the Ziegler-Natta eatalyst, polyolefin has become one of the most important polymers produeed industrially. In particular, polyethylene, polypropylene and ethylene-propylene copolymers have been widely used as commercial products. High resolution solution NMR has become the most powerful analytieal method used to investigate the microstructures of these polymers. It is well known that the tacticity and comonomer sequence distribution are important factors for determining the mechanical properties of these copolymers. Furthermore, information on polymer microstructures from the analysis of solution NMR has added to an understanding of the mechanism of polymerization. 

Brown, J.E., Tryon, M., Mandel.J. Determination of propylene in ethylene-propylene copolymers by infrared spectrometry. Anal. Chem. 35, 2172-2176 (1963). 

Corish,P. J., Small, R.M.B., Wey,P.E. Determination of ethylene-propylene copolymer composition by infrared analysis. Anal. Chem. 33, 1793-1794 (1961). 

Gardner,I.J., Cozewith,C., Ver Strate,G. Infrared determination of composition of ethylene-propylene copolymers. Rubber Chem. Technol. 44, 1015-1024 (1971). 

LomonteJ.N. The infrared spectrum of ethylene-propylene copolymers and the determination of propylene content. Polymer Letters 1, 645-647 (1963). 

Staffer, R.L., Smith,W.E. Determining compositions of labeled ethylene-propylene copolymers. Anal. Chem. 33,1112-1113 (1961). 

Szewczyk, H., Zielasko, A. Determination of propylene in ethylene-propylene copolymers and terpolymers with dienes by infrared spectroscopy. Polimery 13, 415-418 (1968). 

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. 

An allied study aimed at determining the gross composition of an ethylene-propylene copolymer was carried out to determine the feasibility... 

The determination of the composition of ethylene-propylene copolymers at a temp, of200C by means of an IR fibre-optic sensor based on sapphire fibres was studied. LDPE and PP were also investigated. Data are presented on spectra of LDPE and PP at 200C obtained using the sensor, CH3/CH2 ratio after curve fitting versus C2 content, ratio of absorbance at 2950 and 2852/cm versus C2 content and calibration graph of multivariate calibration. 31 refs. 

Infrared microscopy, pFTlR, is a highly attractive technique to map the crystallinity and additive content of polymer samples. " The spatial distribution of the p-nucleating agent in random ethylene propylene copolymer was determined by pFTIR from the sum... 

Hansen, E.W., Redford, K. and 0ysaed, H. (1996) Improvements in the determination of triad distributions in ethylene-propylene copolymers by NMR. Polymer, 37,19-24. 

To check whether values obtained by extrapolating high temperature data to room temperature are correct, the ethylene-propylene copolymer with 40% ethylene [67] was employed. Its very low glass transition allows determination of at 30°0 and therefore comparison of direct values with the extrapolated ones. The retention volumes were determined in the temperature range 63—83°C (average 73 0), values calculated and A and B constants in eqn (6.43) were determined for each polymer-solute system Zjg values were then calculated at 30 G. A good linear dependence of Zjg versus 1/ T was obtained. The ordinates at the origin, slopes, correlation coefficients of lines and X obtained by calculation and by experiment are listed in Table 5.7. 

For reviews on NMR analysis of EP copolymers see, for example (a) Bovey, F. A. Mirau, P. A. NMR of Polymers. Academic Press San Diego, 1996. (b) Randall, J. C. A review of high-resolution liquid carbon-13 nuclear magnetic resonance characterizations of ethylene-based polymers. 7. Mac-romol. Set, Rev. Macromol. Chem. Phys. 1989, C29, 201-317. (c) Randall, J. C. Polymer Sequence Determination. Academic Press New York, 1977. (d) For NMR analysis on EP copolymers from metallocenes see, for example Tritto, I. Fan, Z. Q. Locatelli, P Sacchi, M. C. Camurati, I. Galimberti, M. NMR studies of ethylene-propylene copolymers prepared with homogeneous metallocene-based Ziegler-Natta catalysts. Macromolecules 1995, 28, 3342-3350. 

Determination of Bound Propylene in Ethylene-Propylene Copolymers... 

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