Polymerization of propiolaldehyde. IV. Synthesis of a functional polymer having an ethynyl group

The cationic homopolymerization and copolymerization of propiolaldehyde were carried out with use of boron trifluoride etherate as an initiator at the temperatures of 0 to ?78°C. Poly(ethynyl)oxymethylene was prepared by the homopolymerization at ?78°C, but it was readily depolymerized to the monomer. The cationic copolymerization with styrene at ?78°C proceeded almost exclusively through the aldehyde addition and a new functional copolymer was obtained. With a rise in polymerization temperature, the ethynyl addition was mixed slightly.     

Alternating copolymerization of ethylene with maleic anhydride

The copolymerization of ethylene with maleic anhydride was carried out with γ-radiation and a radical initiator, i.e., 2,2′-azobisisobutyronitrile and diisopropyl peroxydicarbonate under pressure at various reaction conditions. The homopolymerization of neither monomer was observed in this system. In the γ-ray-initiated copolymerization the G value (polymerized monomer molecules per 100 e.v.) was shown to be between 10³ and 10⁴. It was found that the dose rate exponent of the rate is approximately unity, and the rate is proportional to the amount of ethylene monomer. Apparent activation energies of 1.8 and 27.5 kcal./mole were obtained for γ-ray-initiated and AIBN-initiated copolymerization, respectively. Since the composition of copolymer is independent of monomer molar ratio and the molar ratio of ethylene to maleic anhydride in the polymer is approximately unity, the monomer reactivity ratios were obtained as r_E ? 0 and r_M ? 0 for γ-ray-initiated polymerization at 40°C. Alternating copolymerization was, therefore, concluded to occur. Infrared analysis of the copolymer is almost consistent with this. The copolymer in the solid state is amorphous. It is soluble in water, cyclohexane, and dimethylformamide and insoluble in lower alcohols, ether, and aromatic hydrocarbons. The aqueous solution of polymer gave a strong acid.     

Synthesis and characterization of perfluoro‐3‐methylene‐2,4‐dioxabicyclo[3,3,0] octane: Homo‐ and copolymerization with fluorovinyl monomers

The synthesis of perfluoro‐3‐methylene‐2,4‐dioxabicyclo[3,3,0] octane (D), its radical homopolymerization, and copolymerization with fluoroolefins are presented. Fluorodioxolane (D) was synthesized through direct fluorination of the corresponding hydrocarbon precursor in a fluorinated solvent by F₂/N₂ gas. It was polymerized in bulk using perfluorodibenzoyl peroxide as the initiator. The resulting homopolymer had a limited solubility in fluorinated solvents, and its glass transition temperature (T_g) was in the range of 180–190 °C. The polymeric films prepared by casting from hot hexafluorobenzene (HFB) solution were transparent with low refractive index (1.329 at 633 nm). These films were thermally stable (T_d > 350 °C), and were hard and brittle. The copolymers of monomer (D) were prepared with fluorovinyl monomers such as chlorotrifluoroethylene (CTFE), perfluoropropyl vinyl ether, perfluoromethyl vinyl ether, and vinylidene fluoride. The kinetics of radical copolymerization of monomer (D) with CTFE led to the assessment of the reactivity ratios of both comonomers: r_D = 3.635 and r_CTFE = 0.737 at 74 °C, respectively. The copolymers obtained were soluble in HFB and perfluoro‐2‐butyltetrahydrofuran, with T_g in the range of 84–145 °C depending on the copolymer composition. The films of the copolymers were flexible and clear with a low refractive index (1.3350–1.3770 at 532 nm). © 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 47: 6571–6578, 2009     

Cationic copolymerization of ε‐caprolactone and L,L‐lactide by an activated monomer mechanism

The cationic homopolymerization and copolymerization of L,L ‐lactide and ε‐caprolactone in the presence of alcohol have been studied. The rate of homopolymerization of ε‐caprolactone is slightly higher than that of L,L ‐lactide. In the copolymerization, the reverse order of reactivities has been observed, and L,L ‐lactide is preferentially incorporated into the copolymer. Both the homopolymerization and copolymerization proceed by an activated monomer mechanism, and the molecular weights and dispersities are controlled {number‐average degree of polymerization = ([M]₀ ? [M]_t)/[I]₀, where [M]₀ is the initial monomer concentration, [M]_t is the monomer concentration at time t, and [I]₀ is the initial initiator concentration; weight‐average molecular weight/number‐average molecular weight ～1.1–1.3}. An analysis of ¹³C NMR spectra of the copolymers indicates that transesterification is slow in comparison with propagation, and the microstructure of the copolymers is governed by the relative reactivity of the comonomers. © 2006 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 44: 7071–7081, 2006     

Radical copolymerization of chlorotrifluoroethylene with 4‐bromo‐3,3,4,4‐tetrafluorobut‐1‐ene

The radical copolymerization of chlorotrifluoroethylene (CTFE) with 3,3,4,4‐tetrafluoro‐4‐bromobut‐1‐ene (BTFB) initiated by tert‐butylperoxypivalate is presented. The microstructures of the obtained copolymers are determined by means of NMR spectroscopies and elemental analysis and show that random copolymers were obtained. A wide range of poly(CTFE‐co‐BTFB) copolymers is synthesized, containing from 17 to 89 mol % of CTFE. In all the cases, CTFE is the less reactive of both comonomers. T_d^10% values, ranging from 163 up to 359 °C, are dependent on the BTFB content. These variations of thermal property are attributed to the increase in the number of C‐H and C‐Br bonds breakdown when the BTFB molar percentage in the copolymer is higher. T_g values range from 19 to 39 °C and a decreasing trend is observed when increasing the amount of BTFB in the copolymer. This observation arises from the higher flexibility of the copolymer when increasing the number of fluorobrominated lateral chains. These original fluoropolymers bearing reactive pendant bromo groups are suitable candidates for various applications. © 2014 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2014 , 52, 1714–1720     

Kinetics and mechanism of metallocene‐catalyzed olefin polymerization: Comparison of ethylene,propylene homopolymerizations,and their copolymerization

A series of ethylene, propylene homopolymerizations, and ethylene/propylene copolymerization catalyzed with rac‐Et(Ind)₂ZrCl₂/modified methylaluminoxane (MMAO) were conducted under the same conditions for different duration ranging from 2.5 to 30 min, and quenched with 2‐thiophenecarbonyl chloride to label a 2‐thiophenecarbonyl on each propagation chain end. The change of active center ratio ([C^*]/[Zr]) with polymerization time in each polymerization system was determined. Changes of polymerization rate, molecular weight, isotacticity (for propylene homopolymerization) and copolymer composition with time were also studied. [C^*]/[Zr] strongly depended on type of monomer, with the propylene homopolymerization system presented much lower [C^*]/[Zr] (ca. 25%) than the ethylene homopolymerization and ethylene–propylene copolymerization systems. In the copolymerization system, [C^*]/[Zr] increased continuously in the reaction process until a maximum value of 98.7% was reached, which was much higher than the maximum [C^*]/[Zr] of ethylene homopolymerization (ca. 70%). The chain propagation rate constant (k_p) of propylene polymerization is very close to that of ethylene polymerization, but the propylene insertion rate constant is much smaller than the ethylene insertion rate constant in the copolymerization system, meaning that the active centers in the homopolymerization system are different from those in the copolymerization system. Ethylene insertion rate constant in the copolymerization system was much higher than that in the ethylene homopolymerization in the first 10 min of reaction. A mechanistic model was proposed to explain the observed activation of ethylene polymerization by propylene addition. © 2016 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2017 , 55, 867–875     

Kinetics of free-radical copolymerization of α-methylstyrene and styrene

The free-radical copolymerization of α-methylstyrene and styrene has been studied in toluene and dimethyl phthalate solutions at 60°C. Gas chromatography was used to monitor the rate of consumption of monomers. For styrene alone, the measured rate of polymerization R_p and M?_n of the polymer coincided with values expected from previous studies by other workers. Solution viscosity η affected R_p and M?_n of styrene homopolymers and copolymers as expected on the basis of an inverse proportionality between η^1/2 and termination rate. The rate of initiation by azobisisobutyronitrile appears to be independent of monomer feed composition in this system. Molecular weights of copolymers can be accounted for by considering combinative termination only. The effects of radical chain transfer are not significant. A theory is proposed in which the rate of termination of copolymer radicals is derived statistically from an ideal free-radical polymerization model. This simple theory accounts quantitatively for R_p and M?_n data reported here and for the results of other workers who have favored more complicated reaction models because of the apparent failure of simple copolymer reactivity ratios to predict polymer composition. This deficiency results from systematic losses of low molecular weight copolymer species in some analyses. Copolymer reactivity ratios derived with the assumption of a simple copolymer model and based on rates of monomer loss can be used to predict R_p values measured in other laboratories without necessity for consideration of depropagation or penultimate unit effects. The 60°C rate constants for propagation and termination in styrene homopolymerization were taken to be 176 and 2.7 × 10⁷ mole/l.-sec, respectively. The corresponding figures for α-methylstyrene are 26 and 8.1 × 10⁸ mole/l.-sec. These constants account for the sluggish copolymerization behavior of the latter monomer and the low molecular weights of its copolymers. The simple reaction scheme proposed here suggests that high molecular weight styrene–α-methylstyrene copolymers can be produced at reasonable rates at 60°C by emulsion polymerization. This is shown to be the case.     

Kinetics of radical copolymerization of [1‐(fluoromethyl)vinyl]benzene with chlorotrifluoroethylene

The synthesis of [1‐(fluoromethyl)vinyl]benzene (or α‐(fluoromethyl)styrene, FMB) and its radical copolymerization with chlorotrifluorethylene (CTFE), initiated by tert‐butyl peroxypivalate (TBPPi) are presented. The allyl monomer [H₂C = C(CH₂F)C₆H₅] was obtained by electrophilic fluorodesilylation of trimethyl(2‐phenylprop‐2‐en‐1‐yl)silane in 93% yield. A series of seven copolymerization reactions were carried out starting from initial [CTFE]₀/([FMB]₀ + [CTFE]₀) molar ratios ranging from 19.6 to 90.0 mol %. The molar compositions of the obtained poly(CTFE‐co‐FMB) copolymers were assessed by means of ¹⁹F nuclear magnetic resonance spectroscopy. Statistic copolymers were produced with molar masses ranging between 13,800 and 25,600 g/mol. From the Kelen and Tudos method, the kinetics of the copolymerization led to the determination of the reactivity ratios, r_i, of both comonomers (r_CTFE = 0.4 ± 0.2 and r_FMB = 3.7 ± 1.8 at 74 °C) showing that FMB is more reactive than CTFE as well as other halogenated or nonhalogenated monomers involved in the radical copolymerization with CTFE. © 2007 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 45: 3843–3850, 2007     

Synthesis of methallylic monomers bearing ammonium side‐groups and their radical copolymerization with chlorotrifluoroethylene

Methallylic monomers bearing triethyl or 4‐diazabicyclo[2.2.2]octane (DABCO) ammonium side‐groups are prepared and copolymerized with chlorotrifluoroethylene (CTFE). First, three different monomers are synthesized from chloro‐2‐methylprop‐1‐ene or 3‐chloro‐2‐chloromethylprop‐1‐ene in fair to good yields (57–95%). Then, several parameters (initiators, aqueous or solution processes, temperature) of the radical copolymerization of these monomers with chlorotrifluoroethylene are investigated. Various initiators are tested in the presence of ammonium perfluorooctanoate (APFO) as water‐soluble surfactant, and tert‐butyl peroxypivalate/APFO leads to the best results in a mixed solvent (H₂O/CH₃CN/C₄F₅H₅). In all experiments, the radical copolymerization shows that CTFE is more reactive than the methallylic monomer as evidenced by the characterization of poly(CTFE‐co‐M) copolymer by nuclear magnetic resonance spectroscopy and elemental analysis. Thermal degradation of these copolymers by thermogravimetric analyses indicates that the copolymers are stable up to 180 °C without any degradation and have a T_d,10% above 300 °C. Finally, their ionic exchange capacities range between 0.94 and 1.69 meq g^?1. © 2014 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2014 , 52, 1721–1729     

Cationic copolymerization of indene with styrene derivatives: Synthesis of random copolymers of indene with high molecular weight

Random copolymers with high molecular weights of indene and p‐methylstyrene (pMeSt) were synthesized by cationic polymerization with trichloroacetic acid/tin tetrachloride in CH₂Cl₂ at low temperatures. When indene and pMeSt (1:1 v/v), for example, were polymerized at ?40 °C, both monomers were consumed at very similar rates to give a copolymer with high molecular weight [number‐average molecular weight (M_n): 8–9 × 10⁴]. This is indeed quite unexpected behavior for the combination of these two monomers because pMeSt polymerized over 1000 times faster than indene in the homopolymerization under the reaction conditions previously described. The product copolymer of indene and pMeSt had a random monomer sequence in it that was confirmed by NMR analyses and thermal‐property measurements. In sharp contrast with pMeSt, styrene and p‐chlorostyrene, which have no electron‐donating groups on the phenyl ring, led to low molecular weight polymers (M_n < 10,000) in the copolymerization with indene (1:1 v/v). © 2002 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 40: 2449–2457, 2002     

Charge transfer complex formation in in-situ maleic anhydride and N-vinyl caprolactam copolymer and copolymer/organo-montmorillonite nanoarchitectures

The binary copolymerization of maleic anhydride (MA) and N-vinyl caprolactam (VCL) or considered as acceptor (A)?donor (D) monomer systems were used (MA:VCL) 50:50 in BPO (0.5%) as an initiator at 70°C under nitrogen atmosphere. The functional copolymers, having a combination of rigid/flexible linkages and an ability of complex-formation with interlayered surface of organo-silicate, and their nanocomposites have been synthesized. Interlamellar in situ complex-radical copolymerization of intercalated monomer complexes of MA and VCL undergoes with stearyl amine surface modified montmorillonite (O-MMT) and monomer mixtures. Charge transfer complex formation was followed and identified by UV-Vis-NIR spectroscopy. Equilibrium constant (K_AD) molar absorption coefficient (?^AD)) of the complex were determined by the Benesi-Hildebrand, Scott and Ketaalar equations respectively. The results show that copolymerization of MA:VCL system was preceded via alternating copolymerization mechanism. Obtained functional alternating copolymer and copolymer/O-MMT nanostructures were characterized by XRD and TEM.     

Macromers by carbocationic polymerization. IV. Synthesis and characterization of polyisobutenyl methacrylate macromer and its homopolymerization and copolymerization with methyl methacrylate

This article describes the synthesis and characterization of a new macromer, polyisobutenyl methacrylate (PIB-MA), its free-radical homopolymerization and copolymerization with methyl methacrylate (MMA) to afford the graft copolymer poly(methyl methacrylate-g-isobutylene) (PMMA-g-PIB), the characterization of these polymers, and some physical-mechanical (stress-strain) measurements of the graft copolymer. The key intermediate toward the synthesis of the target macromer was the preparation of polyisobutenyl chloride PIB-Cl^t by the minifer technique. As shown by ¹ H-NMR spectroscopy, and independently by IR spectroscopy coupled with M?_n determination, the PIB-MA macromer carries one terminal methacrylate function per polyisobutylene chain. The free-radical homopolymerization of PIB-MA to very high-molecular-weight product was achieved in bulk at 60°C. The free-radical copolymerization of PIB-MA with MMA also occurs readily and is a convenient route to PMMA-g-PIB. The reactivity of PIB-MA is almost identical to that of MMA; however, in highly viscous systems its rate of diffusion to the reaction site is reduced.     

Polymerization of aromatic aldehydes. IV. Cationic copolymerization of phthalaldehyde isomers and styrene

Copolymerizations of three phthalaldehyde isomers (M₂) with styrene (M₁) were carried out in methylene chloride or in toluene with BF₃OEt₂ catalyst. The monomer reactivity ratios were r₁ = 0.77, r₂ = 0 for the meta isomer and r₁ = 0.60, r₂ = 0 for the para isomer. The second aldehyde group of both isomers did not participate in polymerization and acted simply as the electron-withdrawing group, thus reducing the cationic reactivity of these monomers. Copolymerization behaviors of the ortho isomer (o-PhA) were quite different between 0°C and ?78°C. At ?78°C, o-PhA preferentially polymerized to yield “living” cyclopolymers, until an equilibrium concentration of o-PhA monomer was reached. Then, styrene propagated from the living terminal rather slowly. The block structure of the copolymer was confirmed by the chemical and spectroscopic means. In the copolymerization at 0°C, the o-PhA unit in copolymer consisted both of cyclized and uncyclized units. This copolymer seemed to contain short o-PhA sequences. The variation of the o-PhA-St copolymer structure with the polymerization temperature was explained on the basis of whether the polymerization was carried out above or below the ceiling temperature (?43°C) of the homopolymerization of o-PhA.     

Copolymerization of isobutene and α-methylstyrene as a function of reaction conditions

The influence of reaction conditions (solvent, Lewis acid, temperature) on the cationic copolymerization of isobutene and α-methylstyrene was investigated. The crude product consists of low molecular nonprecipitable oligomers, polyisobutene, and poly(isobutene-co-α-methylstyrene). The amount of poly(α-methylstyrene) formed under the reaction conditions used was negligible. The degree of charge separation in the propagating cationic intermediate determines the selectivity of the reaction; that is, incorporation of monomer units into the polymer, ratio of different product fractions, and microstructure. Molecular weight distribution, copolymerization parameters, and sequence-length distribution functions were determined. The softening range of the copolymers depended on their isobutene content but appeared to be constant up to 15% isobutene in copolymers. The degradation temperature of the copolymers was between 340 and 390°C.     

Kinetic Study of Radical Polymerization VIII. A Comprehensive Study of Solution Copolymerization of Vinyl Acetate and Methyl Acrylate by 1H‐NMR Spectroscopy

Radical copolymerization reaction of vinyl acetate (VA) and methyl acrylate (MA) was performed in a solution of benzene‐d₆ using benzoyl peroxide (BPO) as the initiator at 60°C. Kinetic studies of this copolymerization reaction were investigated by on‐line ¹H‐NMR spectroscopy. Individual monomer conversions vs. reaction time, which was followed by this technique, were used to calculate the overall monomer conversion, as well as the monomer mixture and the copolymer compositions as a function of time. Monomer reactivity ratios were calculated by various linear and nonlinear terminal models and also by simplified penultimate model with r _2(VA)=0 at low and medium/high conversions. Overall rate coefficient of copolymerization was calculated from the overall monomer conversion vs. time data and k _p  . k _t ^?0.5 was then estimated. It was observed that k _p  . k _t ^?0.5 increases with increasing the mole fraction of MA in the initial feed, indicating the increase in the polymerization rate with increasing MA concentration in the initial monomer mixture. The effect of mole fraction of MA in the initial monomer mixture on the drifts in the monomer mixture and copolymer compositions with reaction progress was also evaluated experimentally and theoretically.     

Synthesis and modification of new biodegradable copolymers: Serine/glycolic acid based copolymers

Serine/glycolic acid-based biodegradable polymers have been prepared by ring-opening homopolymerization of 3-(O-benzyl)-L -serinylmorpholine-2,5-dione, and ring-opening copolymerization of the morpholine-2,5-dione derivative and L -lactide/ϵ-caprolactone. The homopolymerization was carried out in the melt at 165°C for 3 min using stannous octanoate as the initiator and continued at lower reaction temperatures (130–150°C) for 48 h, using a molar ratio of monomer and initiator of 1000 yielded a polymer of M_n = 4000. The polymer prepared by homopolymerization of the morpholine-2,5-dione derivative was composed of alternating protected serine and glycolic acid residues. Random copolymers of serine and glycolic acid and L -lactic acid/ϵ-caprolactone were synthesized by copolymerization reaction of 3-(O-benzyl)-L -serinylmorpholine-2,5-dione and lactide or ϵ-caprolactone in the melt at 165°C for 3 min and further reaction at 130°C using stannous octanoate as an initiator. The polymers were deprotected and functionalized through the side chain hydroxyl group of serine residues with an acrylate moiety for applications in injectable drug delivery, cell encapsulation. © 1997 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 35 : 1901–1907, 1997     

Polymerization of 1,3‐dienes with functional groups. II. Free‐radical polymerization of N‐(2‐methylene‐3‐butenoyl)piperidine

The free‐radical homopolymerization and copolymerization behavior of N‐(2‐methylene‐3‐butenoyl)piperidine was investigated. When the monomer was heated in bulk at 60 °C for 25 h without an initiator, about 30% of the monomer was consumed by the thermal polymerization and the Diels–Alder reaction. No such side reaction was observed when the polymerization was carried out in a benzene solution with 1 mol % 2,2′‐azobisisobutylonitrile (AIBN) as an initiator. The polymerization rate equation was found to be R_p ∝ [AIBN]^0.507[M]^1.04, and the overall activation energy of polymerization was calculated to be 89.5 kJ/mol. The microstructure of the resulting polymer was exclusively a 1,4‐structure that included both 1,4‐E and 1,4‐Z configurations. The copolymerizations of this monomer with styrene and/or chloroprene as comonomers were carried out in benzene solutions at 60 °C with AIBN as an initiator. In the copolymerization with styrene, the monomer reactivity ratios were r₁ = 6.10 and r₂ = 0.03, and the Q and e values were calculated to be 10.8 and 0.45, respectively. © 2003 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 41: 1545–1552, 2003     

Cationic copolymerization of propylene oxide with tetrahydrofuran. VI. Triphenylmethyl hexafluorophosphate as initiator

Copolymerizations at ?10 to +20°C of propylene oxide (PO) with tetrahydrofuran (THF) were carried out in 1,2-dichloroethane (DCE) under dry, inert atmospheric conditions. Reactions were initiated by triphenylmethyl hexafluorophosphate (TPM-HFP) and subsequently followed by vapor-phase chromatography. Vacuum-dried residual copolymer products (RCP) were analyzed by gel-permeation chromatography (GPC), vapor-pressure osmometry (VPO) and nuclear magnetic resonance spectrometry (NMR). Attempts to homopolymerize THF in equimolar mixtures of DCE and THF at THF/TPMHFP ratios of 1:1 × 10^?3 proved futile, while the homopolymerization of PO under identical operating conditions took place quite readily. Copolymerizations of PO–THF mixtures were easily carried out with high and often complete consumption of both monomers though, more often than not, THF was the principal residual monomer at the end of the 24 hr reaction period since, under no circumstances could additional THF be polymerized when the PO charged was completely consumed. Linearity of plots of ?ln (C₀/C) versus time showed the reactions to be first order with respect to both PO and THF concentrations. Influence of temperature reveals, via Arrhenius plots and overall activation energies (16.0 kcal/mole for PO and 13.0 kcal/mole for THF), that the initiator system functions similarly to other reported systems. Reactivity ratios (0.26 for PO and 0.80 for THF) indicate that monomer units tend to alternate along the chains rather than form extended segments of a given kind. This is supported by NMR analyses of RCP samples. Bimodal GPC distributions observed in the present study suggest that the copolymerization reaction may be proceeding by either a dual mechanism or a two-step process.     

Polymers from multifunctional isocyanates 14. Alternating copolymers from isocyanato alkenes: Copolymerization of 2-propenyl isocyanate with trimethylsilyl methacrylate as electron acceptor monomer

The copolymerization of 2-propenyl isocyanate ( 1 ) with trimethylsilyl methacrylate ( 2 ) has been investigated. 1 is an electron donor monomer with little tendency to undergo homopolymerization, while 2 is an electron acceptor monomer, capable of free radical homopolymerization. Polymerization to low conversion in benzene gave copolymers with preferential incorporation of 2 and a tendency towards alternating copolymers with increasing amounts of 1 in the feed (1 : 1.13 with a 9 : 1 feed ratio of monomers 1 : 2 ). The glass transition temperatures of the amorphous polymers are in the range from 100–70°C, with a T_g of poly(trimethylsilyl methacrylate) being 135°C. Desilylation occurs in the presence of water, causing an exothermal reaction above the glass transition temperature probably with formation of amides, a reaction that can be used for crosslinking. © 1998 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 36: 611–616, 1998     

Determination of initiation rate of copolymerization of acrylonitrile with p-bromophenyl acrylate carried out in N,N-dimethylformamide

Studies of the initiation rate of the copolymerization reaction of acrylonitrile with p-bromophenyl acrylate initiated by azobisisobutyronitrile in dimethylformamide at 60°C are reported. The inhibition method involved use of stable Banfield's radical (N-[1,1-dimethyl 3-(N-oxidophenylimine)butyl]-N-phenylaminyl oxide). In the case of acrylonitrile, a side reaction effect of the initiation with the stable radical was observed along with a retarding effect resulting from inhibition reaction products (2k_df) = 8.2 × 10^?4 min^?1. During the inhibited homopolymerization of p-bromophenyl acrylate a very strong side initiation reaction effect results from the Banfield radical; the inhibition reaction products do not influence the further course of the polymerization reaction. Side initiation effects of the Banfield radical (BR) increase with increasing concentration of p-bromophenyl acrylate. The overall contribution of the side initiation reaction changes for different comonomer mixtures; with their compositions the actual changes are nonadditive. The inhibition reaction products do not influence the further course of copolymerization. The initiation rate in monomer mixtures depends on their composition and may be described by the following relation: