Semicontinuous emulsion copolymerization of acrylonitrile,butyl acrylate,and styrene

Semicontinuous emulsion copolymerization of acrylonitrile (M₁), butyl acrylate (M₂), and styrene (M₃) was investigated. The copolymerization proceeded under the conditions used with a high degree of conversion, whereby a stationary state characterized by a constant monomer mixture composition and a constant composition of the arising copolymer was achieved. From the analytically estimated free monomers and arising copolymer compositions, the reactivity ratios for the pair AN/BA r₁₂ = 0.71, r₂₁ = 1.17 and for the pair AN/Sty r₁₃ = 0.06, r₃₁ = 0.28 were calculated. The applicability of the reactivity ratios found was verified also for the ternary system acrylonitrile/butyl acrylate/styrene.     

Vinyl polymerization by Ziegler catalysts

Summary Methylmethacrylate and styrene were polymerized with Co(acac)₃-AlEt₂ Br catalyst system in benzene at 40°C. Rate of polymerization is linear to monomer concentrations. Maximum percent conversion of polymer was obtained when Al/Co2 with styrene and Al/Co3 with methylmethacrylate. With increase in aging time catalytic activity decreases. Activation energy was found to be 60 KJ mol^–1. with styrene and 40 KJ mol^–1. with methylmethacrylate.The authors arc thankful to the UGC, INDIA for the financial support.     

Radical copolymerization behaviors of styrene and coumarin

The radical copolymerizations of styrene (M₁) with coumarin (M₂) (and 7-acetoxycoumarin) have been first carried out in benzene (and in DMF) at 60° C using AIBN as initiator. The terminal model monomer reactivity ratios (MRR) were determined by Fineman-Ross method, Kelen-Tudos method and nonlinear method. The respective estimated values are r₁ = 43.08, r₂ = 0.63; r₁ = 39.17, r₂ = 0.43; and r₁ = 49.94, r₂ = 1.04 for styrene-coumarin (S-C) system. For styrene-7-acetoxycoumarin (S-AC) system, the values are r₁ = 51.44, r₂ = 1.24; r₁ = 50.56, r₂ = 1.20 and r₁ = 56.23, r₂ = 1.48, respectively. The penultimate model MRRs are determined by Fenn-Barson method and nonlinear method to be r₁= 49.18, r₁ = 2.01, r₂ = r₂ = 0.43 and r₁ = 51.21, r₁ = 0.86, r₂= r₂ =0, respectively, for S-C system; r₁ = 64.76, r₁= 3.46, r₂ = r₂= 1.20 and r₁ = 59.90, r₁ = 0.57, r₂ = r₂ = 0. respectively, for S-AC system. It is found that coumarin is about 1.2 times more reactive toward styrene-terminated radical than 7-acetoxycoumarin for steric reasons. The penultimate model of Fenn-Barson is fairly adequate in describing the copolymerization mechanism of styrene-coumarin system, while the terminal model is more suitable for styrene-7-acetoxycoumarin system.     

Organotin polymers. IV. Binary and ternary copolymerizations of tributyltin acrylate and methacrylate with styrene,allyl methacrylate,butyl methacrylate,butyl acrylate,and acrylonitrile

The monomer reactivity ratios for the copolymerization of tributyltin acrylate with styrene and allyl methacrylate have been found to be r₁ = 0.213, r₂ = 1.910 and r₁ = 0.195, r₂ = 2.257, respectively. Also, the copolymerization parameters of tributyltin methacrylate with styrene and allyl methacrylate were as follows: r₁ = 0.256, r₂ = 1.104 and r₁ = 2.306, r₂ = 1.013. Copolymerization reactions were carried out in solution at 70°C using 1 mole % AIBN, and the copolymer compositions were determined by tin analysis. Ternary copolymerization of the three systems butyl methacrylate–tributyltin methacrylate–acrylonitrile, butyl acrylate–tributyltin methacrylate–acrylonitrile, and styrene–tributyltin acrylate–acrylonitrile have been studied, and the terpolymer composition of each system was determined through tin and nitrogen analyses. The variation of instantaneous and average terpolymer composition with conversion fit satisfactorily the experimental results over a wide range of conversion.     

Neue photoreaktive Polymere mit seitenständigen Dimethylmaleinimid-Gruppen. I. Radikalische homo-und copolymerisation von N-(5-methyl-3-oxa-4-oxo-hexen-5-yl)-dimethylmaleinimid

The homopolymerisation of N-(5-methyl-3-oxo-4-oxo-hexen-5-yl)-dimethylmaleimide (DMI-MA) leads to linear poly(methylmethyacrylates) with pendant lightsensitive dimethylmaleimide groups. Due to steric hindrance of the methyl substitutents, the carbon-double bond is not involved in the reaction, even at conversions of over 90%. The reaction velocity constant for the homopolymerisation is k_p/k = 2,0 – 2,2.10^?2 (65°C, toluene, AIBN) and the activation energy E_a = 62,36 ± 2 KJ/mol^?1. Measurement of the copolymerisation reactivity ratios for the monomer pairs DMI-MA/methacrylic acid (MAS), DMI-MA/methylmethacrylate (MMA) and DMI-MA/ethylacrylate (EA) gave the following values: DMI-MA (r₁): MAS (r₂) = 1,36 ±0,06 : 0,77: ± 0,06; DMI-MA (r₁) : MMA (r₂) = 1,16 ± 0,17:0,475 ± 0,17 and DMI-MA (r₁): EA(r₂) = 1,60 ± 0,15: 0,44 ± 0,15.     

Plasma-induced polymerization

Summary The plasma-induced bulk copolymerization of alphamethyl styrene (MS) with methyl methacrylate (MMA) and with acrylonitrile (AN) was studied at room temperature. The reactivity ratio values: MMA — MS r_MMA= 0.42 r_MS= 0.22 AN — MS r_AN = 0.03 r_MS= 0.14 as well as the configurational parameter = 0.21 for the first system indicate that both systems can be described by the simple terminal model, neglecting the depolymerization reactions.     

Radiation polymerization of acrylonitrile in a viscous system with styrene

Radiation polymerization of acrylonitrile in a viscous system with styrene was performed at ambient temperature by using γ‐rays. It is found that the overall rate of polymerization was accelerated after critical conversion due to the gel effect. As the molar fraction of styrene in monomer feed (f_St) is increased, both the total polymer conversion and molar fraction of acrylonitrile in the copolymer feed (F_AN) were decreased. The monomer reactivity ratios for acrylonitrile and styerne were determined to be r₁ (AN) = 0.25 and r₂ (St) = 2.0, respectively. The copolymers obtained were characterized by Fourier transformed infrared spectra (FTIR), X‐ray diffraction (XRD), scanning electron microscopy (SEM), ¹H‐NMR, and pyrolysis mass spectrometry (PMS). It was found that the slight addition of styrene to acrylonitrile strongly changes crystallinity, morphology, and thermal decomposition of the resulting polymer. ¹H‐NMR measurment of AN/St copolymer showed the appearance of aromatic proton signals and shifted the resonance of the methylene proton to lower chemical shifts. The mass spectra of AN/St copolymers showed fragments of pyrolysates corresponding to oligonitriles with styrene end groups. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 84: 268–275, 2002; DOI 10.1002/app.10324     

Effect of partitioning of monomer on the reactivities of monomers in microemulsion

Copolymerization of styrene and 2‐hydroxyethyl methacrylate (2‐HEMA) was carried out in a microemulsion medium. The composition of the copolymers was estimated using proton ¹H‐NMR. The reactivity ratios of styrene and 2‐HEMA in ternary microemulsions were observed and were considerable different from those reported for solution and bulk polymerization. In monomer pairs with a considerable difference in polarity, partitioning of a monomer between the aqueous phase and the microemulsion droplets develops a concentration gradient, which can be calculated from the distribution coefficient of the monomer between the two phases. This approach has led to more reliable reactivity ratios for the monomers. The study of styrene–2‐HEMA copolymerization in a sodium dodecylsulfate‐based microemulsion resulted in r_S = 3.79 and r_H = 0.17 as apparent reactivity ratios and r_S = 0.57 and r_H = 23.24 as true reactivity ratios for styrene and 2‐HEMA, respectively. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 84: 1832–1837, 2002; DOI 10.1002/app.10401     

Synthesis and characterization of methyl methacrylate/styrene hyperbranched copolymers via living radical mechanism

Free‐radical copolymerizations of N,N‐diethylaminodithiocarbamoylmethylstyrene (inimer: DTCS) with a methyl methacrylate (MMA)/zinc chloride (ZnCl₂) complex were carried out under UV light irradiation. DTCS monomers play an important role in this copolymerization system as an inimer that is capable of initiating living radical polymerization of the vinyl group. The reactivity ratios (r₁ = 0.56 and r₂ = 0.52: DTCS [M₁]; MMA [M₂]) obtained for this copolymerization system were different from a corresponding model system (alternating copolymer) of a styrene and MMA/ZnCl₂ complex (r₁ = 0.25 and r₂ = 0.056). It was found that the hyperbranched copolymers produced exhibited a random branching structure. It was found that the Lewis acid ZnCl₂ formed the complex not only with MMA but also with the carbamate group of inimer. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 89: 2490–2495, 2003     

Synthesis and characterization of styrene–acrylic ester copolymers

Homopolymers and copolymers of styrene and different acrylic esters (i.e., acrylates) were synthesized by the free‐radical solution polymerization technique. Feed ratios of the monomers styrene and cyclohexyl acrylate/benzyl acrylate were 90 : 10, 75 : 25, 60 : 40, 50 : 50, 40 : 60 and 20 : 80 (v/v) in the synthesis of copolymers. All 6 homopolymerizations of acrylic ester synthesis were carried out in N,N(dimethyl formamide) except for the synthesis of poly(cyclohexyl acrylate) (PCA), where the medium was 1,4‐dioxane. Benzoyl peroxide (BPO) and azobisisobutyronitrile (AIBN) were used as initiators. The polymers synthesized were characterized by FTIR, ¹H‐NMR, ¹³C‐NMR spectroscopy, thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), and viscosity measurements. The reactivity ratios were determined by the Fineman–Ross method using ¹H‐NMR spectroscopic data. The reactivity ratios (r) for the copolymerization of styrene (r_S) with cyclohexyl acrylate (r_CA) were found to be r_S = 0.930 and r_CA = 0.771, while for the copolymerization of styrene with benzyl acrylate, the ratios were found to be r_S = 0.755 and r_BA = 0.104, respectively. The activation energies of decomposition (E_a) and glass‐transition temperature (T_g) for various homo‐ and copolymers were evaluated using TGA and DSC analysis. The activation parameters of the viscous flow, voluminosity (V_E) and shape factor (ν) were also computed for all systems using viscosity data. © 2000 John Wiley & Sons, Inc. J Appl Polym Sci 79: 1513–1524, 2001     

Polymers with pendant isocyanate groups. I. Dual synthesis and properties of poly(styrene-co-styryl isocyanate)

The copolymer poly(styrene-co-styryl isocyanate) was synthesized directly by radical initiation from two different monomer pairs: styrene–cinnamoyl azide and styrene–styryl isocyanate. The copolymerization parameters r₁ = 0.93 ± 0.08, r₂ = ?0.7 ± 0.8 for the first monomer pair and r₁ = 7.8 ± 0.6, r₂ = 0 ± 0.3 for the second pair were determined according to the conventional scheme of copolymerization. The intrinsic viscosities and the thermal behavior of the various copolymers were determined. Further, the chemical reactivity of the pendant isocyanate groups toward alcohol and amines was investigated.     

Synthesis and characterization of copolymer of styrene with methacrylic acid initiated by triphenylbismuthonium 1,2,3,4‐ tetraphenylcyclopentadienylide

The radical copolymerization of styrene with methacrylic acid (MAA) initiated by triphenylbismuthonium 1,2,3,4‐tetraphenylcyclopentadienylide in dioxan at 80 ± 0.1 °C for 3 h results in the formation of alternating copolymer as evidenced from the values of reactivity ratios as r₁ (styrene) = 0.03 and r₂ (MAA) = 0.025. The kinetic expression is R_p α [I]^0.5 [Sty] [MAA] and overall energy of activation is computed to be 23 kJ/mol. The FTIR spectrum of the copolymer shows the presence of bands at 3054 cm^?1 assigned to the phenyl group of styrene and at 1724 cm^?1 assigned to the ? COOH group of MAA. The ¹H‐NMR spectrum of the copolymer shows peaks between 7.20 and 7.27 δ assigned to the phenyl protons of styrene and at 12.5 δ assigned to the COOH proton of MAA. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 98: 1838–1843, 2005     

Microstructure determination of the acrylonitrile–styrene–methyl methacrylate terpolymers by NMR spectroscopy

Acrylonitrile–styrene–methyl methacrylate (A–S–M) terpolymers were prepared by photopolymerization using uranyl nitrate ions as photo initiators, which were analyzed by NMR spectroscopy. The terpolymer compositions were determined by Goldfinger's equation using comonomer reactivity ratios: r_as = 0.04; r_sa = 0.31; r_am = 0.17, r_ma = 1.45; r_sm = 0.52; r_ms = 0.47. The terpolymer compositions were also determined from the quantitative ¹³C(¹H)‐NMR spectroscopy. The sequence distribution of the acrylonitrile‐, styrene‐, and methyl methacrylate–centered triads were determined from the ¹³C(¹H)‐NMR spectra of the terpolymers and are in good agreement with triad concentrations calculated from the statistical model. © 1999 John Wiley & Sons, Inc. J Appl Polym Sci 74: 3026–3032, 1999     

Benzoyl peroxide–p‐acetylbenzylidenetriphenyl arsoniumylide initiated copolymerization of citronellol and styrene

Alternating copolymers, containing styrene and citronellol sequences, have been synthesized by radical polymerization using benzoylperoxide (BPO)–p‐acetylbenzylidenetriphenyl arsoniumylide (pABTAY) as initiator, in xylene at 80 ± 1 °C for 3 h under inert atmosphere. The kinetic expression is R_p ∝ [BPO]^0.88 [citronellol]^0.68 [styrene]^0.56 with BPO and R_p ∝ [pABTAY]^0.27 [citronellol]^0.76 [styrene]^0.63 with pABTAY, ie the system follows non‐ideal kinetics in both cases, because of primary radical termination and degradative chain transfer reactions. The activation energy with BPO and pABTAY is 94 kJ mol^?1 and 134 kJ mol^?1, respectively. Different spectral techniques, such as IR, FTIR, ¹H NMR and ¹³C NMR, have been used to characterize the copolymer, demonstrating the presence of alcoholic and phenyl groups of citronellol and styrene. The alternating nature of the copolymer is shown by the product of reactivity ratios r₁ (Sty) = 0.81 and r₂ (Citro) = 0.015 using BPO and r₁ (Sty) = 0.37 and r₂ (Citro) = 0.01 using (pABTAY), which are calculated by the Finemann–Ross method. A mechanism of copolymerization is proposed. © 2001 Society of Chemical Industry     

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.     

Copolymerization of butadiene with styrene using a rare‐earth metal compound – dialkylmagnesium – halohydrocarbon catalytic system

Copolymerizations of butadiene (Bd) with styrene (St) were carried out with catalytic systems composed of a rare‐earth compound, Mg(n‐Bu)₂ (di‐n‐butyl magnesium) and halohydrocarbon. Of all the rare earth catalysts examined, Nd(P₅₀₇)₃–Mg(n‐Bu)₂–CHCl₃ showed a high activity in the copolymerization under certain conditions: [Bd] = [St] = 1.8 mol l^?1, [Nd] = 6.0 × 10^?3 mol l^?1, Mg/Nd = 10, Cl/Nd = 10 (molar ratio), ageing for 2 h, copolymerization at 50 °C for 6–20 h. The copolymer of butadiene and styrene obtained has a relatively high styrene content (10–30 mol%), cis‐1,4 content in butadiene unit (85–90%), and molecular weight ([η] = 0.8–1 dL g^?1). Monomer reactivity ratios were estimated to be r_Bd = 36 and r_St = 0.36 in the copolymerization. © 2002 Society of Chemical Industry     

Controllable radical copolymerization of styrene and methyl methacrylate using 1,1,2,2‐tetraphenyl‐1,2‐bis(trimethylsilyloxy) ethane as initiator

Copolymerization of styrene (St) and methyl methacrylate (MMA) was carried out using 1,1,2,2‐tetraphenyl‐1,2‐bis (trimethylsilyloxy) ethane (TPSE) as initiator; the copolymerization proceeded via a “living” radical mechanism and the polymer molecular weight (M_w) increased with the conversion and polymerization time. The reactivity ratios for TPSE and azobisisobutyronitrile (AIBN) systems calculated by Finemann–Ross method were r_St = 0.216 ± 0.003, r_MMA= 0.403 ± 0.01 for the former and r_St= 0.52 ± 0.01, r_MMA= 0.46 ± 0.01 for the latter, respectively, and the difference between them and the effect of polymerization conditions on copolymerization are discussed. Thermal analysis proved that the copolymers obtained by TPSE system showed higher sequence regularity than that obtained by the AIBN system, and the sequence regularity increased with the content of styrene in copolymer chain segment. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 82: 1474–1482, 2001     

Determination of monomer reactivity ratios in styrene/2‐ethylhexylacrylate copolymer

The monomer reactivity ratios for styrene/2‐ethylhexylacrylate in bulk at 80°C were investigated by studying the resulting copolymer composition via ¹H‐NMR. Composition results were summarized and various methods were employed to estimate the reactivity ratios including the use of the Error‐in‐Variables‐Model (EVM) approach by using the Mayo–Lewis model. The estimates of the reactivity ratios from the EVM method are found to be r_s = 0.979 and r_EHA = 0.292. The resulting copolymer has a tendency toward alternation with an azeotrope of f(styrene) = 0.972. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 92: 3368–3370, 2004     

Reactivity ratios and copolymer properties of 2‐(diisopropylamino)ethyl methacrylate with methyl methacrylate and styrene

Free radical copolymerization kinetics of 2‐(diisopropylamino)ethyl methacrylate (DPA) with styrene (ST) or methyl methacrylate (MMA) was investigated and the corresponding copolymers obtained were characterized. Polymerization was performed using tert‐butylperoxy‐2‐ethylhexanoate (0.01 mol dm^?3) as initiator, isothermally (70 °C) to low conversions (<10 wt%) in a wide range of copolymer compositions (10 mol% steps). The reactivity ratios of the monomers were calculated using linear Kelen–Tüd?s (KT) and nonlinear Tidwell–Mortimer (TM) methods. The reactivity ratios for MMA/DPA were found to be r₁ = 0.99 and r₂ = 1.00 (KT), r₁ = 0.99 and r₂ = 1.03 (TM); for the ST/DPA system r₁ = 2.74, r₂ = 0.54 (KT) and r₁ = 2.48, r₂ = 0.49 (TM). It can be concluded that copolymerization of MMA with DPA is ideal while copolymerization of ST with DPA has a small but noticeable tendency for block copolymer building. The probabilities for formations of dyad and triad monomer sequences dependent on monomer compositions were calculated from the obtained reactivity ratios. The molar mass distribution, thermal stability and glass transition temperatures of synthesized copolymers were determined. Hydrophobicity of copolymers depending on the composition was determined using contact angle measurements, decreasing from hydrophobic polystyrene and poly(methyl methacrylate) to hydrophilic DPA. Copolymerization reactivity ratios are crucial for the control of copolymer structural properties and conversion heterogeneity that greatly influence the applications of copolymers as rheology modifiers of lubricating oils or in drug delivery systems. © 2015 Society of Chemical Industry     

Polystyrene with trifluoromethyl units: Monomer reactivity ratios,thermal behavior,flammability, and thermal degradation kinetics

Chemical modification based on incorporation of flame retardants (FR) into the polymer backbone was used in order to reduce polystyrene flammability. 3‐(trifluoromethyl)styrene (StCF₃) and 3,5‐bis(trifluoromethyl)styrene (St(CF₃)₂) were applied as reactive FR. Copolymers were synthesized with different feed ratios and it gave series of copolymers with various amounts of StCF₃ and St(CF₃)₂ (5–50% mol/mol of St). Glass transition temperature (T_g) and thermal stability of obtained (co)polymers were determined from differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA), respectively. Kinetic parameters such as the thermal decomposition activation energy (E) and frequency factor (A) were estimated by Ozawa and Kissinger models. Pyrolysis combustion flow calorimeter (PCFC) was applied as a tool for assessing the flammability of the synthesized (co)polymers. Relative reactivity ratios were determined by applying the conventional linearization Jaacks method (r_St = 1.34_, r_StCF3 = 0.54), (r_St = 0.47_, r_St(CF3)2 = 0.13). The results suggest that incorporation of fluorinated styrenes into PSt enchance flame retardance. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 42839.