Studies on Synthesis and Characterization of Charge Transfer Polymerization of Styrene and Alkyl Methacrylates

Abstract

Copolymers involving styrene and homologues of alkyl methacrylates (viz., methyl, ethyl, and butyl methacrylates) were synthesized at 60°C by employing a mixture of n‐butylamine and carbontetrachloride as charge transfer (CT) initiators in dimethyl sulphoxide medium. The CT complex was characterized by UV spectroscopy while the respective copolymers were characterized by employing infrared (IR) and ¹H NMR spectroscopy. The copolymer compositions were determined by using ¹H NMR spectroscopy and the reactivity ratios were computed by Fineman–Ross (F–R) and Kelen–Tudos (K–T) methods. The reactivity ratios of Sty‐MMA and Sty‐EMA copolymers indicate that higher level of styrene is incorporated in the copolymer. On the other hand the Sty‐BMA system exhibits different behavior. The higher value of r ₂ is obtained denoting that BMA is more active than styrene and hence, more BMA is present in the copolymer chain. In Sty‐MMA and Sty‐BMA systems, the product of r ₁ and r ₂ is greater than 1, representing the formation of high degree of random copolymers. However, in the case of Sty‐EMA, the product of r ₁ and r ₂ is less than 1 indicating the formation of alternating copolymer.     

Alternating Copolymers of Limonene with Methyl Methacrylate: Kinetics and Mechanism

The radical copolymerization of limonene (optically active) with methyl methacrylate in xylene at 80±0.1°C for 1 hr, initiated by benzoyl peroxide (BPO) yield alternating copolymer(s), under the inert atmosphere of nitrogen, as evidenced by reactivity ratios r₁ (MMA)=0.07 and r₂ (limonene)=0.012 using the Kelen–Tüdos method. The kinetic expression is Rα[I]^0.5[MMA]^1.0[Lim.]^?1.0. The decrease in the rate of polymerization with increase in concentration of limonene is due to penultimate unit effect. The overall energy of activation is calculated as 49 kJ/mole. FTIR of the copolymer(s) shows the characteristic frequencies at 1732.40 and 2951.40 cm^?1 due to –OCH₃ of MMA and aromatic C–H stretching of limonene, respectively. ¹H NMR spectra shows peak at 3.8–4.1 δ and 5.3–5.6 δ due to –OCH₃ of MMA and trisubstituted olefinic protons [–CH=CH–CH₂–] of limonene, respectively.     

Synthesis and characterization of copolymers of limonene with styrene initiated by azobisisobutyronitrile

The radical copolymerization of limonene with styrene by azobisisobutyronitrile in xylene at 80 ± 0.1 °C for 2 h, under inert atmosphere of N₂, yields alternating copolymers. The kinetic expression is R_p∝[I]^0.5[Sty]^1.0[Lim]^−1.0. The overall activation energy is calculated as 41 kJ/mol. The FTIR and ¹H-NMR spectra of copolymers show bands at 3000 and 1715 cm⁻¹ and peaks at 6.8 δ and 5.3 δ due to phenyl protons of styrene and trisubstituted olefinic protons of limonene, respectively. The values of reactivity ratios r₁(Sty)=0.0625 and r₂(Lim)=0.014, calculated by Kelen-Tüdos method. The Alfrey-Price Q-e parameters for limonene are 0.438 and −0.748, respectively. The penultimate unit effect is favoured in the present system and the value of φ is 38.49.     

Copolymerization of n‐butylacrylate with methylmethacrylate by a novel photoinitiator, 1‐(bromoacetyl)pyrene

The photopolymerization efficiency of pyrene (Py), 1‐acetylpyrene (AP), and 1‐(bromoacetyl)pyrene (BP) for copolymerization of n‐butylacrylate (BA) with methylmethacrylate (MMA) was compared. A kinetic study of solution copolymerization in DMSO at 30 ± 0.2°C showed that the Py could not initiate copolymerization even after 20 h, whereas with AP as initiator, less than 1% conversion was observed. However, introduction of a Br in α‐methyl group of AP significantly enhanced the percent conversion. The kinetics and mechanism of copolymerization of BA with MMA using BP as photoinitiator have been studied in detail. The system follows nonideal kinetics (R_p α [BP]^0.67[BA]¹[MMA]^0.98), and degradative solvent transfer reasonably explains these kinetic nonidealities. The monomer reactivity ratios (MRRs) of MMA and BA have been estimated by the Finemann–Ross and Kelen–Tudos methods, by analyzing copolymer compositions determined by ¹H‐NMR spectra. The values of r₁ (MMA) and r₂ (BA) were found to be 2.17 and 0.44, respectively, which suggested the high concentration of alternating sequences in the random copolymers obtained. © 2007 Wiley Periodicals, Inc. Int J Chem Kinet 39: 261–267, 2007     

p-ACETYLBENZYLIDENE TRIPHENYLARSONIUM YLIDE (p-ABTAY) INITIATED RADICAL COPOLYMERIZATION OF METHYLMETHACRYLATE WITH STYRENE

p-Acetylbenzylidene triphenylarsonium ylide (p-ABTAY) initiated radical copolymerization of methylmethacrylate (MMA) with styrene in dioxane, at 60 ± 0.1°C, under the inert atmosphere of nitrogen yields alternating copolymer, as evidenced by ¹H NMR spectroscopy. The kinetic equation for the present system is Rp μ[p-ABTAY]^0.46 [MMA] [Sty]. The rate of copolymerization (Rp) is proportional to the square root of [p-ABTAY] indicating bimolecular termination. The values of kp²/kt and energy of activation have been computed as 6.3 × 10^?3 l mol^?1s^?1 and 63 KJ mol l^?1, respectively. The reactivity ratios have been calculated as r₁ (MMA) = .60, r₂ (Sty) = .35, by using the Kelen-Tudös method. The copolymerization reaction is initiated by the phenyl free radical. The formation of phenyl radicals may be attributed to the pp-dp overlap between the hybridized sp² orbital and the larger and more diffuse 4d orbital of arsenic.     

Determination of reactivity ratios and kinetics of free radical copolymerization of linalool with styrene

Copolymerization of acyclic monoterpenoid, namely linalool (LIN), with styrene (STY) initiated by benzoyl peroxide (BPO) p‐acetyl benzylidene triphenyl arsonium ylide (p‐ABTAY) in xylene separately at 80°C for 180 min under inert atmosphere of nitrogen was performed. The results give a nearly alternating copolymer as evidenced from reactivity ratios (r₁ = 0.016, r₂ = 0.057) w.r.t. BPO; (r₁ = 0.017, r₂ = 0.052) w.r.t. p‐ABTAY (i.e. r₁ = 0.0165 ± 0.0005 and r₂ = 0.0545 ± 0.0025 per initiator set) using Kelen–Tudos method. The FT‐IR spectrum shows a band at 3026 cm^?1 due to the aromatic ring of polystyrene and an alcoholic band of linalool at 3408 cm^?1. ¹H‐NMR spectrum shows peaks at δ 7.0–7.7 ppm of ? OH protons and peaks at δ 7.5–8.0 ppm due to phenyl protons of styrene. The system follows ideal kinetics i.e. Rp ∝ [LIN]^1.0[STY]^1.0[BPO]^0.5/[p‐ABTAY]^0.5. The overall energy of activation in the temperature range 75–85°C is 77.0 kJ mol^?1 and 90.0 kJ mol^?1, respectively. The values for Mark–Houwink constants for the functional copolymer has been evaluated as a = 0.40 and K = 1.60 × 10^?4 with the help of gel permeation chromatography (GPC). Alfrey–Price, Q and e parameters for linalool have been evaluated as Q₂ = 0.80; e₂ = 1.25 w.r.t. BPO and Q₂ = 0.90; e₂ = 1.54 w.r.t. p‐ABTAY. Thermal properties of copolymers were investigated by thermogravimetric analysis (TGA) techniques. Copyright © 2004 John Wiley & Sons, Ltd.     

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

Abstract

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.     

Synthesis and characterisation of copolymers containing geraniol and styrene initiated by benzoyl peroxide

Alternating copolymer(s) containing geraniol and styrene sequences have been synthesized by using benzoyl peroxide as initiator in xylene at 80 °C. The copolymerisation follows ideal kinetics. The formation of the copolymer is confirmed by the presence of peaks at 7-7.5δ due to the phenyl group and 7-7.7δ due to the alcoholic group and 2900 cm⁻¹ due to the phenyl groups in the FTIR spectrum of the copolymer. The values of r₁(Sty)=0.76 and r₂(Ger)=0.03, calculated by the Kelen-Tüdos method, indicates some alternating nature of the copolymer. The glass transition temperature (T_g) found by differential scanning calorimetry, is 90 °C. The Alfrey-price Q-e parameters for geraniol are 0.221 and 0.649.     

Kinetic study of copolymerization of linalool and methyl methacrylate initiated by selenonium ylide

Free radical copolymerization of an acyclic monoterpenoid linalool (LIN) and methyl methacrylate (MMA) in dioxan was carried out in dilatometer under an inert atmosphere of nitrogen for 90 min at 60 ± 1°C by using diphenyl selenonium 2,3,4,5‐tetraphenylcyclopentadienylide (selenonium ylide) as an initiator. The kinetic expression of the reaction is R_p ∝ [ylide]^0.5[MMA]^1.0[LIN]^1.0. The activation energy of copolymerization was estimated to be 43.7 kJ mol^?1. The formation of a functional copolymer is evidenced by spectral analysis. The copolymer was characterized by FTIR, ¹H NMR, ¹³C NMR, DSC, and TGA analysis. © 2010 Wiley Periodicals, Inc. Int J Chem Kinet 43: 43–52, 2011     

Metal-Ylide Complex-Initiated Radical Copolymerization of Methylmethacrylate and Styrene

Abstract

Phenacyl dimethylsulfonium ylide complex of mercuric chloride (PDSY-HgCl₂)-initiated radical copolymerization of styrene with methylmethacrylate (MMA) at 85 ± 0.1°C using dioxane as an inert solvent yields random copolymers as evidenced by NMR spectroscopy. The kinetic equation for the present system was R_p α [PDSY-HgCl₂]^0.5 [Sty]^1.0 [MMA]^1.0. The values of energy of activation (ΔE) and k² _p/k₁ were 48.0 kJ mol^?1 and 8.6 × 10^?4 L mol^?1 s^?1, respectively. The mechanism of the reaction has also been proposed for the present system. The properties of copolymer were studied in the form of film. The film was highly absorptive for nitric acid but less absorptive for acetic acid. The film was water impermeable.     

Synthesis and Characterization of Novel Methacrylic Copolymers: Determination of Monomer Reactivity Ratios

A new methacrylic monomer, 4‐nitro‐3‐methylphenyl methacrylate (NMPM) was prepared by reacting 4‐nitro‐3‐methyl phenol dissolved in methyl ethyl ketone (MEK) in the presence of triethylamine as a catalyst. Copolymerization of NMPM with methyl methacrylate (MMA) has been carried out in methyl ethyl ketone (MEK) by free radical solution polymerization at 70±1°C utilizing benzoyl peroxide (BPO) as initiator. Poly (NMPM‐co‐MMA) copolymers were characterized by FT‐IR, ¹H‐NMR and ¹³C‐NMR spectroscopy. The molecular weights (M_w and M_n) and polydispersity indices (M_w/M_n) of the polymers were determined using a gel permeation chromatograph. The glass transition temperatures (T_g) of the copolymers were determined by a differential scanning calorimeter, showing that T_g increases with MMA content in the copolymer. Thermogravimetric analysis of the polymers, performed under nitrogen, shows that the stability of the copolymer increases with an increase in NMPM content. The solubility of the polymers was tested in various polar and non‐polar solvents. Copolymer compositions were determined by ¹H‐NMR spectroscopy by comparing the integral peak heights of well separated aromatic and aliphatic proton peaks. The monomer reactivity ratios were determined by the Fineman‐Ross (r₁ =7.090:r₂=0.854), Kelen‐Tudos (r₁=7.693: r₂=0.852) and extended Kelen‐Tudos methods (r₁=7.550: r₂= 0.856).     

Nitroxide‐mediated radical copolymerization of methyl methacrylate controlled with a minimal amount of 9‐(4‐vinylbenzyl)‐9H‐carbazole

The controlled nitroxide‐mediated homopolymerization of 9‐(4‐vinylbenzyl)‐9H‐carbazole (VBK) and the copolymerization of methyl methacrylate (MMA) with varying amounts of VBK were accomplished by using 10 mol % {tert‐butyl[1‐(diethoxyphosphoryl)‐2,2‐dimethylpropyl]amino} nitroxide relative to 2‐({tert‐butyl[1‐(diethoxyphosphoryl)‐2,2‐dimethylpropyl]amino}oxy)‐2‐methylpropionic acid (BlocBuilder?) in dimethylformamide at temperatures from 80 to 125 °C. As little as 1 mol % of VBK in the feed was required to obtain a controlled copolymerization of an MMA/VBK mixture, resulting in a linear increase in molecular weight versus conversion with a narrow molecular weight distribution (M_w /M_n ≈ 1.3). Preferential incorporation of VBK into the copolymer was indicated by the MMA/VBK reactivity ratios determined: r_VBK = 2.7 ± 1.5 and r_MMA = 0.24 ± 0.14. The copolymers were found significantly “living” by performing subsequent chain extensions with a fresh batch of VBK and by ³¹P NMR spectroscopy analysis. VBK was found to be an effective controlling comonomer for NMP of MMA, and such low levels of VBK comonomer ensured transparency in the final copolymer. © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2011     

Synthesis and Radical Polymerization of N‐[4‐N′‐(Phenylamino‐carbonyl)phenyl]maleimide and its Copolymerization with Methyl Methacrylate

A novel type of imide‐amide monomer, 4‐maleimidobenzanilide (MB) i.e., N‐[4‐N′‐(phenylaminocarbonyl)phenyl]maleimide was synthesized from maleic anhydride, p‐aminobenzoic acid and aniline. Radical polymerization of MB and its copolymerization with MMA (methyl methacrylate), initiated by AIBN, were performed in THF solvent at 65°C. Nine copolymer samples were prepared using different feed ratios of comonomers. All the polymer samples have been characterized by a solubility test, intrinsic viscosity measurements, FT‐IR and ¹H‐NMR spectral analysis, and thermo‐gravimetric analysis. The values of monomer reactivity ratios of MB‐MMA system (r₁, r₂) and the Alfrey‐Price parameters Q₁ and e₁ were determined.     

Copolymerization of ethylene with styrene catalyzed by a linked bis(phenolato) titanium catalyst

Copolymerization of ethylene with styrene, catalyzed by 1,4‐dithiabutanediyl‐linked bis(phenolato) titanium complex and methylaluminoxane, produced exclusively ethylene–styrene copolymers with high activity. Copolymerization parameters were calculated to be r_E = 1.2 for ethylene and r_S = 0.031 for styrene, with r_E r_S = 0.037 indicating preference for alternating copolymerization. The copolymer microstructure can be varied by changing the ratio between the monomers in the copolymerization feed, affording copolymers with styrene content up to 68%. The copolymer microstructure was fully elucidated by ¹³C NMR spectroscopy revealing, in the copolymers with styrene content higher than 50%, the presence of long styrene–styrene homosequences, occasionally interrupted by isolated ethylene units. © 2006 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 44: 1908–1913, 2006     

Curcumin,a natural colorant as initiator for photopolymerization of styrene: kinetics and mechanism

The photopolymerization of styrene in presence of an efficient, eco-friendly, and a cost-effective photoinitiator, curcumin, which is found in turmeric root, has been reported for the first time. The catalytic concentration (10⁻⁶ M) of curcumin is effective to photoinitiate the polymerization of styrene. The kinetic data, inhibiting effect of benzoquinone and electron spin resonance studies, indicate that the polymerization proceeds via a free radical mechanism. The system follows non-ideal kinetics (R _p ∝ [Cur]^0.36 [Sty]^1.04) due to both primary radical termination and degradative chain transfer reactions. The broad peaks due to methine and methylene protons in ¹H-NMR (nuclear magnetic resonance [NMR]) spectrum and a band of resonances at 145–146 ppm in ¹³C-NMR indicate atactic nature of the polystyrene formed. The maximum conversion at 30 ± 0.2 °C in 17 h has been limited to 23% without gelation. The formation of radicals and mechanism of polymerization are also discussed.     

1-(Bromoacetyl)pyrene,a novel photoinitiator for the copolymerization of styrene and acrylonitrile

A comparative study on photoinitiated solution copolymerization of Styrene (Sty), with acrylonitrile (AN) using pyrene, 1-acetylpyrene, and 1-(bromoacetyl)pyrene (BrPy) as initiators, showed that the introduction of a chromophoric moiety, bromoacetyl (–COCH₂Br), significantly increased the photoinitiating ability of pyrene. The kinetics and mechanism of copolymerization of Sty with AN (Sty–co–AN) using BrPy as photoinitiator has been studied in detail. The kinetic data, inhibiting effect of benzoquinone, and electron spin resonance (ESR) studies suggest that the polymerization proceeds via a free radical mechanism. The system followed non-ideal kinetics (R _p α[BrPy]^0.7[Sty]^1.09[AN]^1.01) and degradative solvent transfer reasonably explained these kinetic non-idealities. The co-monomer reactivity ratios calculated by using the Finemann–Ross and Kelen–Tudos models were r ₁ (Sty) = 0.39 and r ₂ (AN) = 0.05. The reactivity ratios strongly indicate that the two monomers enter in almost alternating arrangement along the copolymer chain.     

Styrene/1,3‐butadiene copolymerization by C2‐symmetric group 4 metallocenes based catalysts

C₂‐symmetric group 4 metallocenes based catalysts (rac‐[CH₂(3‐tert‐butyl‐1‐indenyl)₂]ZrCl₂ (1) , rac‐[CH₂(1‐indenyl)₂]ZrCl₂ (2) and rac‐[CH₂(3‐tert‐butyl‐1‐indenyl)₂]TiCl₂ (3) ) are able to copolymerize styrene and 1,3‐butadiene, to give products with high molecular weight. In agreement with symmetry properties of metallocene precatalysts, styrene homosequences are in isotactic arrangements. Full determination of microstructure of copolymers was obtained by ¹³C NMR and FTIR analysis and it reveals that insertion of butadiene on styrene chain‐end happens prevailingly with 1,4‐trans configuration. In the butadiene homosequences, using zirconocene‐based catalysts, the 1,4‐trans arrangement is favored over 1,4‐cis, but the latter is prevailing in the presence of titanocene (3) . Diad composition analysis of the copolymers makes possible to estimate the reactivity ratios of copolymerization: zirconocenes (1) and (2) produced copolymers having r₁ × r₂ = 0.5 and 3.0, respectively (where 1 refers to styrene and 2 to butadiene); while titanocene (3) gave tendencially blocky styrene–butadiene copolymers (r₁ × r₂ = 8.5). The copolymers do not exhibit crystallinity, even when they contain a high molar fraction of styrene. Probably, comonomer homosequences are too short to crystallize (n_s = 16, in the copolymer at highest styrene molar fraction). © 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 1476–1487, 2008     

Vinyl polymerization with a binary system of p‐chlorobenzenediazonium salt and sodium tetraphenylborate

A combined system of sodium tetraphenylborate (STPB) and p‐chlorobenzenediazonium tetrafluoroborate (CDF) serves as an effective initiator at low temperatures for acrylate monomers such as methyl methacrylate (MMA), ethyl acrylate, and di‐2‐ethylhexyl itaconate. The polymerization of MMA with the STPB/CDF system has been kinetically investigated in acetone. The polymerization shows a low overall activation energy of 60.3 kJ/mol. The polymerization rate (R_p) at 40 °C is given by R_p = k[STPB/CDF]^0.5[MMA]^1.6, when the molar ratio of STPB to CDF is kept constant at unity, suggesting that STPB and CDF form a complex with a large stability constant and play an important role in initiation and that MMA participates in the initiation process. From the results of a spin trapping study, p‐chlorophenyl and phenyl radicals are presumed to be generated in the polymerization system. A plausible initiation mechanism is proposed on the basis of kinetic and electron spin resonance results. A large solvent effect on the polymerization can be observed. The largest R_p value in dimethyl sulfoxide is 11 times the smallest value in N,N‐dimethylformamide. The copolymerization of MMA and styrene with the STPB/CDF system gives results somewhat different from those of conventional radical copolymerization. © 2001 John Wiley & Sons, Inc. J Polym Sci Part A: Polym Chem 39: 4206–4213, 2001     

Investigating polymer blend miscibility with forward recoil spectrometry

We tested forward recoil spectrometry (FRES) as a method to determine miscibility by measuring coexistence compositions in binary polymer blends. In this study, equilibrium phase compositions were determined for a compositionally symmetric poly(styrene‐ran‐methyl methacrylate) random copolymer (S_0.49‐r‐MMA) and two homopolymers, deuterated polystyrene (dPS) and deuterated poly(methyl methacrylate) (dPMMA). Sample preparation, film dewetting, and beam damage were addressed, and the results for these polymer blends were in good agreement with those obtained through other experimental techniques. Deuteration had a strong effect on the miscibility of the dPS/S_0.49‐r‐MMA and dPMMA/S_0.49‐r‐MMA blends, to the extent that the asymmetric miscibility observed separately for the PS/S_0.49‐r‐MMA and PMMA/S_0.49‐r‐MMA blends was not found. Although this deuteration effect may limit the applicability of FRES for some polymer systems, the accuracy with which phase compositions can be determined with FRES makes it an attractive alternative to other less quantitative methods for investigating blend miscibility. © 2000 John Wiley & Sons, Inc. J Polym Sci B: Polym Phys 38: 1547–1552, 2000     

Photosensitized copolymerization of optically active N-l-menthylmaleimide with styrene and methyl methacrylate

Photosensitized copolymerization of optically active N-l-menthylmaleimide (NMMI) with styrene (Sty) and methyl methacrylate (MMA) was carried out in tetrahydrofuran (THF) at 30°C with benzoyl peroxide (BPO). The monomer reactivity ratios for the copolymerization of NMMI (M₂) with Sty (M₁) and MMA (M₁) were r₁ = 0.08 ± 0.10, r₂ = 0.20 ± 0.05 and r₁ = 2.85 ± 0.06, r₂ = 0.07 ± 0.06, respectively. Copoly-MMA–NMMI and poly-NMMI showed positive circular dichroism(CD) curves of equal intensity and shape over the wavelength region from 230 to 270 nm; copoly-Sty–NMMI also showed a positive CD curve which was similar in shape but was different in intensity from that of poly-NMMI. The correlation between monomer unit ellipticity of the copolymers and their composition would suggest the alternating and stereoregular copolymerization of NMMI with Sty.