Ethylene Propylene Copolymers. I. Monomer Reactivity Ratios

1966 ◽  
Vol 39 (2) ◽  
pp. 241-247
Author(s):  
R. D. Bushick
Keyword(s):  
Catalyst System ◽  
Reactivity Ratio ◽  
Reactivity Ratios ◽  
Feed Concentration ◽  
Monomer Reactivity Ratios ◽  
Ethylene Propylene ◽  
Random Arrangement ◽  
Catalyst Systems

Abstract Copolymerization of ethylene and propylene with diisobutylaluminum chloride and various vanadium-containing compounds gave a series of reactivity ratio values for ethyleno which decreased in the order: VO(O−n−Bu)3>VOCl(OEt)2>VOCl2OEt>VO(OEt)3≃VOCl3. All of the catalyst systems were extremely sensitive to changes in the ethylene feed concentration. The reactivity ratio product suggested a random arrangement of monomer units with each catalyst system except VOC13.

scholarly journals Polymers Based on Methacrylate Bearing Coumarin Side Group: Synthesis via Free Radical Polymerization, Monomer Reactivity Ratios, Dielectric Behavior, and Thermal Stabilities

2012 ◽  
Vol 2012 ◽  
pp. 1-13 ◽  
Author(s):  
Nursel Ayaz ◽  
Feride Bezgin ◽  
Kadir Demirelli
Keyword(s):  
Free Radical ◽  
Radical Polymerization ◽  
Free Radical Polymerization ◽  
Reactivity Ratio ◽  
Dielectric Behavior ◽  
Reactivity Ratios ◽  
Monomer Reactivity Ratios ◽  
Thermal Stabilities ◽  
Dichloromethane Solution ◽  
H Nmr

Copolymerization and homopolymerization of 7-methacryloyloxy coumarin (MAOC) and its copolymers with benzyl methacrylate (BMA), methyl methacrylate (MMA), ethyl methacrylate (EMA), and isobuthyl methacrylate (IBMA) were performed by the free radical polymerization method (FRP) at low conversions (<15%). The resulting polymers were characterized by FTIR, 1H NMR, GPC, DSC, and TGA. The monomer reactivity ratios of MAOC and BMA were computed using Kelen-Tüdös (K-T) and Fineman-Ross (F-R) methods and were found to be r1=0.45, r2=1.29; r1=0.46; r2=1.33, respectively (r1 is monomer reactivity ratio of MAOC). Blends of poly(MAOC) and poly(BMA) obtained via FRP method were prepared by casting films from dichloromethane solution and were characterized by DTA and TGA techniques. Dielectric measurements for MAOC homopolymer and its copolymers with EMA, MMA, and IBMA were carried out by means of an impedance analyzer as a function of temperature and frequence. Dielectric properties of polymer samples prepared in a plate form were measured at room temperature over the frequency range 0.1 kHz–2 MHz and given as compared with each other.

Percipitation copolymerization of acrylamide and acrylic acid: Determination of reactivity ratio by various methods

e-Polymers ◽  
2012 ◽  
Vol 12 (1) ◽  
Author(s):  
Sedigheh Nazaripour ◽  
Mehdi Rafizadeh ◽  
Hosein Bouhendi
Keyword(s):  
Hydrogen Bonding ◽  
Acrylic Acid ◽  
Reactivity Ratio ◽  
Copolymer Composition ◽  
Reactivity Ratios ◽  
Nonlinear Method ◽  
Monomer Reactivity Ratios ◽  
Polymerization Method ◽  
Acid Determination

AbstractCopolymers of acrylamide ( AM ) and acrylic acid ( AA) were prepared by precipitation polymerization method at 65 °C in the ethyl acetate as solvent. Copolymer composition was determined by elemental analysis. Monomer reactivity ratios were determined in low conversions. Mayo-Lewis, Finemann-Ross, Inverted Finemann-Ross, Ezrielev-Brokhina-Roskin, Kelen-Tudos, Extended Kelen-Tudos and Mao-Huglin methods, as linear methods, and Tidwell-Mortimer, as nonlinear method, were applied to calculate rAM and rAA r reactivity ratios. Monomer reactivity ratios of AM and AA were obtained 0.46 and 0.28, respectively. Comparing of reactivity ratios of AM and AA in this work by other solvents showed that hydrogen bonding and ionic strength are important parameters that can affect the reactivity ratios of monomers. Moreover, microstructure of copolymers was determined using reactivity ratios and conditional probability based on the kinetic model for free-radical polymerization.

Contribution to the Study of Ethylene-Propylene Copolymers by Infrared Spectroscopy. Distribution of Monomeric Units

1965 ◽  
Vol 38 (2) ◽  
pp. 334-342 ◽  
Author(s):  
Giovanni Bucci ◽  
Tonino Simonazzi
Keyword(s):  
Infrared Spectroscopy ◽  
Numerical Evaluation ◽  
Distribution Functions ◽  
Reactivity Ratios ◽  
Block Polymers ◽  
Ethylene Propylene ◽  
Copolymer Microstructure ◽  
Catalyst Systems ◽  
Random Alternation ◽  
Theoretical Considerations

Abstract Elastomeric properties of ethylene-propylene copolymers depend not only on the composition but also on the copolymer microstructure, i.e., on the distribution of monomeric units along the macromolecular chain. According to Natta and coworkers the best polymer should be obtained when two monomeric units are randomly alternated in the macromolecule. The random alternation of the monomers is actually only partial because somewhat longer homosequences are formed. In such a case one deals with block polymers. On the basis of some theoretical considerations on the copolymerization process and also on the basis on the reactivity ratios of the two monomers, Natta and coworkers have calculated the distribution functions of sequences for various catalyst systems. Infrared spectroscopy has been widely used in connection with this problem though from different viewpoints and with different aims. The purpose of our work is to reanalyze the whole problem. We have focused our attention on the CH2 rocking band in the sequence (—CH2—)n, where n varies from 1 to 5 or more. Some disagreement exists between various authors on the assignment of these bands, especially in the case of the (—CH2—)3 and (—CH2—)4 sequences. We have then divided our work as follows: (a) assignment of infrared bands in the spectral region between 900 and 650 cm−1; (b) calculation of absorbances at various frequencies; (c) attempt at a numerical evaluation of the distribution of monomeric units.

Monomer Sequence Distribution in Ethylene Propylene Elastomers. I. Measurement by Carbon-13 Nuclear Magnetic Resonance Spectroscopy

1971 ◽  
Vol 44 (3) ◽  
pp. 781-804 ◽  
Author(s):  
C. J. Carman ◽  
C. E. Wilkes
Keyword(s):  
Chemical Shifts ◽  
Catalyst System ◽  
Reactivity Ratio ◽  
Sequence Length ◽  
Copolymer Composition ◽  
Resonance Spectroscopy ◽  
Sequence Distribution ◽  
Ethylene Propylene ◽  
Average Value ◽  
Monomer Sequence

Abstract The carbon-13 chemical shifts of ethylene propylene copolymers were found to be very sensitive to monomer sequence distribution. Methylene resonances were interpreted in terms of methylene sequence length and tertiary carbon resonances were interpreted in terms of propylene centered pentad sequences. Propylene inversion was detected and measured quantitatively in the spectra. A formula was derived for calculating r1·r2, which is independent of monomer feed, and which is based on measuring contiguous and isolated propylene sequences in the copolymer. The interpretations are shown to be consistent for copolymers containing 26, 34, and 62 mole% propylene. The r1·r2 products were determined for each of these polymers. Calculation of copolymer composition based on the 13C chemical shift assignments gave excellent agreement with the compositions as determined by infrared and 1H NMR. A formula was derived, based on copolymerization theory, for calculating the reactivity ratio product, r1·r2, directly from the copolymer composition (% ethylene) and the ratio of contiguous to isolated propylene sequences. Using this formula an average value for r1·r2=0.42±0.02 was determined for the copolymers made with vanadium acetylacetonate-diethylaluminum chloride catalyst system.

Copolymerization of Isobutene and Isoprene at “High” Temperature with Syncatalyst Systems Based on Aluminum Organic Compounds

1976 ◽  
Vol 49 (4) ◽  
pp. 937-959 ◽  
Author(s):  
S. Cesca ◽  
M. Bruzzone ◽  
A. Priola ◽  
G. Ferraris ◽  
P. Giusti
Keyword(s):  
Energy Savings ◽  
Ion Pairs ◽  
Great Part ◽  
Methyl Chloride ◽  
Reactivity Ratio ◽  
Experimental Conditions ◽  
Noticeable Increase ◽  
Catalyst Systems ◽  
Kinetics Of ◽  
Kinetics Of Vulcanization

Abstract New catalyst systems based on alkylaluminum derivatives and halogen or interhalogen compounds were found highly efficient in the synthesis of high-molecular-weight IIR at temperatures above − 50°C. The reaction mechanism was studied in detail for the system Et2AlCl + Cl2. The reactions occurring between chlorine, isobutene, Et2AlCl, and the solvent (CH3Cl) were elucidated and studied under various experimental conditions (e.g. presence or absence of light, simultaneous presence of the copolymerization system components, temperature, type of halogen, use of model compound of isobutene). It was concluded that halogenium ions, i.e. Cl+, Br+, or I+, are the initiating species. Kinetic and conductometric investigations showed that scarcely dissociated ion pairs, e.g. Cl+[Et2AlCl2]−, were formed in the absence of monomer; but in the presence of isobutene, a noticeable increase of the electrical conductivity and rapid polymerization occurred. The maximum polymerization rate was first order with respect to the concentrations of monomer, Cl2, and Et2AlCl. In the homopolymerization of isobutene, transfer to monomer and termination reactions were negligible. The MW of IIR was found to be mainly dependent on the concentrations of the catalyst components, on isoprene concentration, and on temperature. The reactivity ratio of isobutene with isoprene was found to be r1=2.5±0.5 at −35°C, while the activation energies relative to MW were −5.8 ± 0.4, kcal/mol for polyisobutene, and −5.7 ± 0.7 and − 4.3 ± 0.5 kcal/mol for IIR containing, respectively, 1.3 and 1.9 mol% of isoprene. The evaluation of some physicochemical and technological properties of typical IIR produced with the system Et2AlCl + Cl2, indicated that isoprene is randomly distributed along the chains and that the MWD is monomodal, while the glass transition temperature, tensile properties, mechanical-dynamic spectra, and kinetics of vulcanization are very similar to those of commercial IIR. Very preliminary data, referring to several classes of new catalyst systems yielding IIR having good properties, were also obtained. The syncatalyst systems here described can work in a homogeneous phase consisting of an aliphatic hydrocarbon besides methyl chloride, still giving IIR with high MW. Therefore, a completely homogeneous process can be envisioned for the synthesis of IIR at −50°C thus avoiding a great part of the fouling problems of the slurry process. The economic advantage of using “high” temperatures of polymerization is briefly discussed in terms of energy savings.

Copolymers of 4-nitrophenyl acrylate with styrene: Synthesis, characterization and monomer reactivity ratios

1996 ◽  
Vol 32 (1) ◽  
pp. 105-109 ◽  
Author(s):  
S. Thamizharasi ◽  
P. Gnanasundaram ◽  
K.Venkata Rao ◽  
A.Venkata Rami Reddy
Keyword(s):  
Reactivity Ratios ◽  
Monomer Reactivity Ratios
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