Monomer Reactivity Ratios In Copolymerization Research Articles

Polycarboxylate superplasticizers of acrylic acid–isobutylene polyethylene glycol copolymers: monomer reactivity ratios, copolymerization behavior and performance

Acrylic acid–isobutylene polyethylene glycol (AA-TPEG) copolymers are typical of polycarboxylate superplasticizers (PCEs). AA-TPEG copolymers are prepared via free-radical polymerization with potassium persulfate as the initiator. The obtained copolymers were characterized by gel permeation chromatography (GPC) and infrared spectra (FTIR). The GPC method can break through the former limitations of the instruments and receive instantaneous unreacted and instantaneous monomer concentrations and not the initial monomer feeds. Since TPEG monomer is highly bulky, the common calculation methods for determining monomer reactivity ratios in copolymerization based on terminal copolymerization equation are not suitable. However, this study created non-linear least squares curve fitting of terminal copolymerization equation (NLLSQ-T) and penultimate copolymerization equation (NLLSQ-P) methods, which used Python’s NumPy, SciPy, and SymPy libraries to generate code and did numerical computations, bringing greater accuracy of monomer reactivity ratios. The monomer reactivity ratios were calculated with Fineman–Ross, Kelen–Tudos, YBR, NLLSQ-T, and NLLSQ-P methods and found to be r AA = 10.888, r′ AA = 1.131, r TPEG = 0.012, and r′ TPEG = 0.042 for AA-TPEG copolymers. Moreover, this study also explored specific copolymerization behavior of similar structure of copolymers with steric hindrance under penultimate copolymerization equation, such as dependence of the mole fractions in the copolymer on the mole fractions of unreacted monomers in solution, variation of copolymer compositions with conversion and sequence length distribution. The fluidity and flow loss of pastes containing PCEs were investigated, and the appropriate PCEs dosages resulted in a better workability of cement pastes.

Polymerization of 1,3‐dienes containing functional groups: 8. Free‐radical polymerization of 2‐triethoxysilyl‐ 1,3‐butadiene

AbstractThe presence of a bulky substituent at the 2‐position of 1,3‐butadiene derivatives is known to affect the polymerization behavior and microstructure of the resulting polymers. Free‐radical polymerization of 2‐triethoxysilyl‐1,3‐butadiene (1) was carried out under various conditions, and its polymerization behavior was compared with that of 2‐triethoxymethyl‐ and other silyl‐substituted butadienes. A sticky polymer of high 1,4‐structure ($E:Z \approx 8:2$) was obtained in moderate yield by 2,2′‐azobisisobutyronitrile (AIBN)‐initiated polymerization. A smaller amount of Diels–Alder dimer was formed compared with the case of other silyl‐substituted butadienes. The rate of polymerization (Rp) was found to be Rp = k[AIBN]0.5[1]1.2, and the overall activation energy for polymerization was determined to be 117 kJ mol−1. The monomer reactivity ratios in copolymerization with styrene were r1 = 2.65 and rst = 0.26. The glass transition temperature of the polymer of 1 was found to be −78 °C. Free‐radical polymerization of 1 proceeded smoothly to give the corresponding 1,4‐polydiene. The 1,4‐E content of the polymer was less compared with that of poly(2‐triethoxymethyl‐1,3‐butadiene) and poly(2‐triisopropoxysilyl‐1,3‐butadiene) prepared under similar conditions. Copyright © 2010 Society of Chemical Industry

Copolymers of 4‐(3′,4′‐Dimethoxycinnamoyl)phenyl Acrylate and MMA: Synthesis, Characterization, Photocrosslinking Properties, and Monomer Reactivity Ratios

4‐(3′,4′‐Dimethoxycinnamoyl)phenyl acrylate (DMCPA) containing pendant chalcone moiety was copolymerized with methyl methacrylate (MMA) by radical polymerization in ethyl methyl ketone at 70°C under a nitrogen atmosphere using benzoyl peroxide (BPO) as a free radical initiator. The prepared polymer was characterized by UV, FT‐IR, 1H‐NMR, and 13C‐NMR spectra. The composition of the copolymer was determined using 1H‐NMR analysis. The monomer reactivity ratios of copolymerization were determined using conventional linearization methods such as Fineman–Ross (r 1 = 0.26 and r 2 = 0.61), Kelen–Tudos (r 1 = 0.26 and r 2 = 0.61), and Ext. Kelen–Tudos (r 1 = 0.23 and r 2 = 0.59), and a non‐linear error‐in‐variables model (EVM) method using the computer program RREVM (r 1 = 0.2541 and r 2 = 0.6094). The molecular weights (M w and M n) of the copolymers were determined by gel permeation chromatography. Thermogravimetric analysis of the polymers in air reveals that the stability of the copolymers decreases with an increase in the mole fraction of MMA in the copolymers. The solubility of the polymers was tested in various polar and non‐polar solvents. The glass transition temperature of the copolymers was determined as a function of copolymer composition. The copolymers were sensitive to UV light and became crosslinked after irradiation with 254 nm light.

A STUDY OF COPOLYMERIZATION WITH 4-BROMOBENZYL METHACRYLATE AND ETHYL METHACRYLATE

ABSTRACT 4-Bromobenzyl methacrylate [BrBMA] monomer was synthesized from a reaction of sodium methacrylate with 4-bromobenzylbromide. The copolymerization of this monomer with ethyl methacrylate (EMA) and its homopolymerization were carried out in a 1,4-dioxane solution at 60°C using 2,2′-azobisisobutyronitrile [AIBN] as initiator. The monomer and the polymers were characterized by IR, 1H and 13C-NMR techniques. The composition of monomeric units in the copolymer system was calculated using 1H-NMR spectroscopy by comparing the integral values of well separated aromatic and aliphatic proton peaks. The monomer reactivity ratios of copolymerization were determined by using the Kelen-Tüdös (K-T), Inverted Fineman-Ross (IFR) and Yezrielev-Brokhina-Roskin (YBR) methods, and were found to be r1=0.44, r2=0.63 and r1=0.24, r2=0.47 and r1=0.37, r2=0.64, respectively (r1 is the monomer reactivity ratio of BrBMA). Based on the experimental data of the K-T method, triad analysis was performed. It is concluded that this copolymerization results in statistical-type macromolecules. The solubility parameters and the glass transition temperature of the copolymers were determined as a function of copolymer composition.

Synthesis of a new monomerN?-(?-methacryloyloxyethyl)-2-pyrimidyl-(p-benzyloxycarbonyl)aminobenzenesulfonamide and its copolymerization withN-phenyl maleimide

The new monomer N′-(β-methacryloyloxyethyl)-2-pyrimidyl-(p-benzyloxy- carbonyl)aminobenzenesulfonamide (MPBAS) (M1) is synthesized using sulfadiazine as parent compound. It could be homopolymerized and copolymerized with N-phenyl maleimide (NPMI) (M2) by radical mechanism using AIBN as initiator at 60 °C in dimethylformamide. The new monomer MPBAS and polymers were identified by IR, element analysis and 1H NMR in detail. The monomer reactivity ratios in copolymerization were determined by YBR method, and r1 (MPBAS) = 2.39 ± 0.05, r2 (NPMI) = 0.33 ± 0.02. In the presence of ammonium formate, benzyloxycarbonyl groups could be broken fluently from MPBAS segments of copolymer by catalytic transfer hydrogenation, and the copolymer with sulfadiazine side groups are recovered. © 2000 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 38: 2548–2554, 2000

Determination of the monomer reactivity ratios for copolymerization of itaconic acid and acrylamide by conductometric titration method

Compositions of low conversion itaconic acid-acrylamide (IA-AAm) copolymers synthesized with solution polymerization in aqueous medium by using potassium persulfate under nitrogen atmosphere were determined by conductometric titration method. The results were evaluated by various linear and nonlinear methods. The monomer reactivity ratios were found to be r IA=1.47±0.03, r AAm=0.76±0.02 with Fineman–Ross, r IA=1.25±0.10, r AAm=0.67±0.05 with Kelen–Tüdös, r IA=1.65±0.21, r AAm=0.88±0.08 with Tidwell–Mortimer methods. For this system, the analysis of results show that IA is a more reactive monomer in IA-AAm copolymerization.

Determination of monomer reactivity ratios for copolymerizations of methacrylic acid with poly (ethylene glycol) monomethacrylate

Self-associating copolymers of methacrylic acid (MAA) with poly (ethylene glycol) monomethacrylate (PEGMA) were prepared by free radical copolymerization of MAA with PEGMA using dispersion polymerization in D2O, or solution polymerization in a 50/50 ethanol–D2O mixture. These copolymers have been studied as components of reversible hydrogels1 and in medical applications.2 In order to understand the relationship between the copolymer structure and its performance, it is important to determine the sequence distribution of the copolymer. The copolymer architecture is determined by the reactivity ratios and integrated instantaneous feed compositions. The reactivity ratios were determined using the first-order Markov method3 by running a series of reactions at various initial monomer ratios and determining the monomer incorporation into the copolymer as a function of time, via 1H nuclear magnetic resonance. The reactivity ratios for dispersion copolymerizations of MAA with PEGMA in water were determined to be r1 = 1.03 and r2 = 1.02, whereas solution copolymerization in 50/50 EtOH–H2O gave reactivity ratios of r1 = 2.0 and r2 = 3.6. These results show that the reactivity ratios and copolymer architecture are influenced by the solvent system. © 1998 John Wiley & Sons, Inc. J Appl Polym Sci 68: 1019–1025, 1998

Determination of monomer reactivity ratios for copolymerizations of methacrylic acid with poly (ethylene glycol) monomethacrylate

Determination of monomer reactivity ratios for copolymerizations of methacrylic acid with poly (ethylene glycol) monomethacrylate

Synthesis of high-vinyl polymers and copolymers of butadiene on the basis of a new soluble organosodium catalyst

A new process for the synthesis of high-vinyl (50–70 % 1.2-units) butadiene polymers and copolymers on the basis of hydrocarbon-soluble organosodium catalyst is proposed. The catalyst can be readily synthesized in aliphatic solvents from commercially available starting materials; the equipment common for the synthesis of organolithiums is suitable. Main parametres of butadiene polymerization and styrene-butadiene copolymerization including kinetics, molecular weights and monomer reactivity ratios for copolymerization were investigated. The synthesis of polystyrene, 3.4-polyisoprene, styrene-butadiene block-copolymers, non-functional butadiene and styrene-butadiene liquid rubbers, and other high-vinyl polymers is also possible.

Radical polymerization of methyl trans‐β‐vinylacrylate

AbstractMethyl trans‐β‐vinylacrylate (MVA) undergoes radical polymerization with α,α′‐azobis(isobutyronitrile) (AIBN) in bulk and solution. The polymer obtained consists of 85% trans‐1,4 and 15% trans‐3,4 units. Poly(MVA) (PMVA) is readily soluble in common organic solvents, but insoluble in n‐hexane and petroleum ether. PMVA exhibits a glass transition at 60°C, and loses no weight up to 300°C in nitrogen. The kinetics of MVA homopolymerization with AIBN was investigated in benzene. The rate of polymerization (Rp) can be expressed by Rp = k[AIBN]0.5[MVA]1.0, and the overall activation energy has been calculated to be 94 kJ/mol. The propagation radical of MVA at 80°C was detected by ESR spectroscopy, which indicated that the unpaired electron of the propagating radical was completely delocalized over the three allyl carbons. Furthermore, the steady‐state concentration of the propagating radical of MVA at 60°C was determined by ESR spectroscopy, and the propagation rate constant (kp) was calculated to be 1.25 X 102 L/mol ·s. Monomer reactivity ratios in copolymerization of MVA (M2) with styrene (M1) are r1 = 0.16 and r2 = 4.9, from which Q and e values of MVA are calculated as 4.2 and ‐0.32, respectively. © 1995 John Wiley & Sons, Inc.

Organotin polymers—XIX. Copolymerization parameters of p-acryloyloxy-tri-N-butyltin benzoate with allyl methacrylate, N-vinylpyrrolidone and vinyl acetate

Radical copolymerizations of p-acryloyloxy-tri-n-butyltin benzoate (ABTB) with allyl methacrylate, N-vinyl pyrrolidone and vinyl acetate were carried out in solution at 70° using 1 mol% azobisisobutyronitrile as initiator. The copolymer compositions were determined from tin analyses. The monomer reactivity ratios for copolymerizations of ABTB (monomer-1) with allyl methacrylate, N-vinyl pyrrolidone and vinyl acetate have been found to be r 1 = 0.28, r 2 = 0.89; r 1 = 0.07; r 2 = 0.40 and r 1 = 0.92, r 2 = 0.99, respectively. The Q and e values for the organotin monomer were calculated.

Radical polymerization of 4‐methylene‐4H‐1,3‐benzodioxin‐2‐ones: Cyclic α‐substituted styrenes

Abstract4‐Methylene‐4H‐1,3‐benzodioxin‐2‐one (MBDOON), an α‐substituted cyclic styrene derivative, was synthesized and polymerized readily with 2,2′‐azobis(isobutyronitrile) (AIBN) as an initiator in solution. The kinetics of the MBDOON homopolymerization with AIBN was investigated in N‐methyl‐2‐pyrrolidone (NMP). The rate of polymerization, Rp, can be expressed by Rp − k[AIBN]0.52[MBDOON]1.1 and the overall activation energy has been calcualted to be 75.7 kJ/mol. Monomer reactivity ratios in copolymerization of MBDOON (M2) with styrene (M1) are r1 = 0.31 and r2 = 3.20, from which Q and e values of MBDOON can be calculated as 3.0 and −0.7, respectively. Ring‐substituted MBDOON monomers such as 6‐chloro, 6‐methyl, and 7‐methoxy derivatives were synthesized and polymerized with AIBN. The 6‐substituted MBDOON's readily underwent radical polymerization while the 7‐methoxy‐MBDOON was slower to polymerize. Poly(MBDOON) is predominantly heterotactic. (rr = 35, mr = 46, and mm = 19%). The polymer releases carbon dioxide at about 200°C and is converted with some depolymerization to poly[(o‐hydroxyphenyl)acetylene]. The thermolysis temperature is very much affected by the ring substituent. The onset of carbon dioxide liberation was observed at 140°C in the case of the 7‐methoxyl derivative while the 6‐substituents had a smaller effect on the decarboxylation temperature. © 1993 John Wiley & Sons, Inc.

Copolymers of 2‐vinyl‐4,4‐dimethylazlactone with styrene and ethyl α‐hydroxymethylacrylate

AbstractThe monomer reactivity ratios for copolymerization of 2‐vinyl‐4,4‐dimethylazlactone (VA) and ethyl α‐hydroxymethylacrylate (EHMA) were 0.20–0.24 and 0.53–0.74, respectively, which show that EHMA is slightly more reactive with VA than with itself and should lead to random copolymers favoring alternation. The VA–styrene (VA–St) system also has a tendency to form random copolymers but with increased tendency for alternation with both r1 and r2 between 0.18–0.22. Tg's of VA–EHMA and VA–St copolymers varied between 100 and 136°C, and 96 and 117°C, respectively. Thermolysis of VA–EHMA copolymers resulted in crosslinking via the ring‐opening reaction of VA groups by EHMA alcohols, followed by transesterification involving EHMA units at higher temperatures leading to highly crosslinked structures. The performed dimer of EHMA and VA was also synthesized and found to be an effective crosslinking agent in free radical vinyl polymerizations.

Radical polymerization of N‐phenyl‐α‐methylene‐β‐lactam

AbstractN‐phenyl‐α‐methylene‐β‐lactam (PML), a cyclic analog of N,N‐disubstituted methacrylamides which do not undergo radical homopolymerization, was synthesized and polymerized with α,α′‐azobis (isobutyronitrile) (AIBN) in solution. Poly (PML) (PPML) is readily soluble in tetrahydrofuran, chloroform, pyridine, and polar aprotic solvents but insoluble in toluene, ethyl acetate, and methanol. PPML obtained by radical initiation is highly syndiotactic (rr = 92%), exhibits a glass transition at 180°C, and loses no weight upto 330°C in nitrogen. The kinetics of PML homo‐polymerization with AIBN was investigated in N‐methyl‐2‐pyrrolidone. The rate of polymerization (Rp) can be expressed by Rp = k[AIBN]0.55[PML]1.2 and the overall activation energy has been calculated to be 87.3 kJ/mol. Monomer reactivity ratios in copolymerization of PML (M2) with styrene (M1) are r1 = 0.67 and r2 = 0.41, from which Q and e values of PML are calculated as 0.60 and 0.33, respectively.

Preparation of a thermally phase‐separating copolymer, poly(N‐isopropylacrylamide‐co‐N‐acryloxysuccinimide), with a controlled number of active esters per polymer chain

AbstractN‐isopropylacrylamide and N‐acryloxysuccinimide have been copolymerized in various mixtures of terrahydrofuran and toluene using azobisisobutyronitrile as initiator. Polymerization has been conducted for 24 h at 50°C under a slightly positive pressure of nitrogen. The copolymers were assayed for active ester content by measuring the UV absorbance (259 nm) of N‐hydroxysuccinimide anion, generated by reacting the copolymers with N‐isopropylamine in dimethylformamide and dissolving the resulting mixture in 0.1M HEPES buffer, pH 7.5. The molecular weight and its distribution have been estimated by gel permeation chromatography. The active ester content was found to be equivalent to the comonomer feed ratio, and the major factor controlling the molecular weight was the ratio of tetrahydrofuran to toluene. Thus, the number of active esters per polymer chain could be controlled by adjustment of the comonomer feed ratio and the ratio of tetrahydrofuran to toluene. Monomer reactivity ratios for copolymerization of N‐isopropylacrylamide with N‐acryloxysuccinimide were also estimated. These copolymers are useful for immobilizing binding ligands such as antibodies for subsequent thermally induced precipitation immunoassays and bioseparation processes.

Direct polar conjugation in radical copolymerization of styrene with substituted styrenes

The electronic effects of substitutents on the values of monomer reactivity ratios in copolymerization of styrene with substituted styrenes have been isolated. The most important proved to be the direct polar conjugation of the substitutent with the nucleophilic reaction centre. A two-parameter correlation equation has been proposed which describes satisfactorily the experimentally determined reactivity of comonomers. The values of monomer reactivity ratios have been determined for copolymerization of styrene with para and meta-substituted aminostyrenes.

Reactivities of monomers towards the 1-phenylethyl radical

The reactivities of styrene, methyl acrylate, methyl methacrylate, methyl isopropenyl ketone, methyl vinyl ketone and 2-vinylpyridine towards the 1-phenylethyl radical at 100° have been compared using acenaphthylene as the reference monomer. Binary copolymerizations with acenaphthylene were initiated by 1,1′[ 13C]azobis-1,1′-phenylethane; 13C-NMR spectroscopy was used to compare the numbers of initiator fragments attached to the two types of monomeric units in each of the various copolymers. The relative reactivities of the monomers towards the initiating radical match their relative reactivities towards the polystyrene radical, as deduced from monomer reactivity ratios for copolymerizations with styrene.

Comments on the Kuo‐Chen method to determine monomer reactivity ratios in copolymerization

Comments on the Kuo‐Chen method to determine monomer reactivity ratios in copolymerization

Organotin polymers. IX. Copolymerization parameters of di-(tri-n-butyltin) itaconate with styrene and methyl methacrylate

Copolymerization reactions of di-(tri-n-butyltin) itaconate with styrene and methyl methacrylate were carried out in solution at 70°C using 1 mol% azobisisobutyronitrile as a free radical initiator. The copolymer compositions were determined by chemical analysis as well as from 1H-NMR data. The monomer reactivity ratios for copolymerizations of di-(tri-n-butyltin) itaconate with styrene and methyl methacrylate have been found to be r1 = 0.228, r2 = 0.677, and r1 = 0.220, r2 = 1.635, respectively. The sequence distribution of the triad fractions were calculated from reactivity ratios and compared with those obtained from 1H-NMR data.

Comparative recalculation of the monomer reactivity ratios in copolymerization for styrene and methyl methacrylate

AbstractThe monomer reactivity ratios (MMRs) in radical copolymerization for styrene and methyl methacrylate were recalculated by five different methods using literature copolymerization data. The use of approximate 95% confidence limits and their visual inspection helps to separate possibly biased copolymer composition data. The recalculated mean MRR values were r1 (styrene) = 0.501 ± 0.031 and r2 = 0.472 ± 0.031. The results of the linear least‐squares calculation procedures seldom approach the quality of the nonlinear least‐squares analysis according to the method of Tidwell and Mortimer.