Radical polymerization of new functional monomers: Mono- and dimethacryloyl isocyanate containing bisphenol-A and its derivatives

New functional monomers mono-and dimethacryloyl isocyanate containing bisphenol-A were prepared on reaction of methacryloyl isocyanate (MAI) with bisphenol-A (BPA) and its derivatives at low temperature. The monomers thus obtained were characterized with IR, UV, and ¹H- and ¹³C-NMR spectra. Radical polymerization of mono-and dimethacryloyl isocyanate containing bisphenol-A and its derivatives was studied in terms of the rate of polymerization, solvent effect, copolymerization, thermal properties, and kinetic measurements of photocrosslinking. Polar solvents such as DMSO and NMP were found to slow the polymerization. Copolymerization of BPA-MAI (M₁) with MMA (M₂) in DMF was studied at 90°C. The monomer reactivity ratio was calculated to be r₁ = 0.17 and r₂ = 1.34 according to the method of Fineman–Ross. Functional polymers containing the allyl group were successfully modified and photocrosslinked on irradiation in the presence of benzoin isopropyl ether. The photocrosslinking process follows second-order kinetics. © 1996 John Wiley & Sons, Inc.     

Radical polymerization of methacryloyl isocyanate containing 1-adamantanol

Summary Radical polymerization of the methacryloyl isocyanate containing 1-adamantanol (Ad-MAI) with AIBN in different solvents at 60°C was investigated. It is observed that polymerization is slower in polar solvents than in nonpolar ones. The rate of polymerization for Ad-MAI was found to be slower than those of Adph-MAI and MMA both in photopolymerization and in thermal polymerization. Copolymerization of Ad-MAI (M₁) with styrene (M₂) in benzene was studied at 60°C. The monomer reactivity ratio was calculated to be r₁=1.53 and r₂=0.76 according to the method of Fineman-Ross. The prominent glass transition temperature for poly(Ad-MAI) was observed at 142°C from global TSC spectrum. Received: 20 November 1998/Revised version: 16 February 1999/Accepted: 25 February 1999     

Monomer apparent reactivity ratios for acrylonitrile/ammonium itaconate radical copolymerization systems

Ammonium itaconate was first used to copolymerize with acrylonitrile. This was achieved by using azobisisobutyronitrile as the initiator and dimethyl sulfoxide as the solvent. Effects of copolymerization systems on monomer apparent reactivity ratios for acrylonitrile/ammonium itaconate copolymers were studied. The values of monomer apparent reactivity ratios were calculated by Kelen‐Tudos method. The apparent reactivity ratios in the aqueous suspension polymerization system are similar to those in the solution polymerization system at polymerization conversions of less than 18% [reactivity ratio of acrylonitrile (r_AN) = 0.47 ± 0.01, reactivity ratio of ammonium itaconate (r_AIA) = 3.08 ± 0.01]. At conversions of more than 50%, the changes of monomer apparent reactivity ratios become less prominent (r_AN = 0.68 ± 0.01, r_AIA = 2.47 ± 0.01). In water‐rich reaction medium [(H₂O/dimethylsulfoxide (DMSO) > 80/20)], the monomer apparent reactivity ratios are approximately equivalent to those in the aqueous suspension polymerization system. In DMSO‐rich reaction medium (DMSO/H₂O > 80/20), the apparent reactivity ratios are similar to those in the solution polymerization system. With an increase in the polarity of the solvent, the values of apparent reaction ratios both decrease. The values of apparent reaction ratios gradually tend to 1 with increasing the copolymerization temperature. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 103: 3920–3923, 2007     

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     

Coordination copolymerization of butadiene and isoprene with rare earth chloride–alcohol–aluminum trialkyl catalytic systems

Butadiene and isoprene were copolymerized with LnCl₃–ROH–AIR₃ catalytic system. The products obtained were confirmed to be copolymers by their glass transition temperatures and characteristic pyrolytic chromatograms, etc. The equation for copolymerization rate may be expressed as R_p = K_p(M)²(cat). The rate constants of copolymerization, activation energy, and monomer reactivity ratios for catalytic systems containing various rare earth elements in III-B family and different solvents were determined. It was found that the reactivity ratio of butadiene was greater than that of isoprene and r₁r₂ near 1, and the composition and microstructure of copolymers were not much affected by variation of polymerization conditions. Both monomer repeat units in the copolymers had cis-1,4 contents above 95%, which is a distinguishing feature of coordination polymerization with the lanthanide catalyst system.     

Sequence determination of vinyl acetate–methyl acrylate copolymers by NMR spectroscopy

Vinyl acetate/methyl acrylate (V/M) copolymers were prepared by free-radical solution polymerization in benzene. Copolymer compositions were obtained from ¹H-NMR spectroscopy. Reactivity ratios for the copolymerization of V with M were calculated using the Kelen-Tudos (KT) and the nonlinear error in variables (EVM) methods. The reactivity ratios obtained from the KT and EV methods are r_V = 0.04 ± 0.03 and r_M = 7.28 ± 2.88 and r_v = 0.04 ± 0.01 and r_M = 7.28 ± 0.37, respectively. The microstructure was obtained in terms of the distribution of V- and M-centered triad sequences from ¹³C{¹H}-NMR spectra of copolymers. Homonuclear ¹H-2D-COSY and 2D-NOESY NMR were used to determine the most probable conformer for the V/M copolymer. The copolymerization behavior of the V/M copolymers as a function of conversion is also reported. © 1994 John Wiley & Sons, Inc.     

Monomer reactivity ratios for acrylonitrile/ammonium itaconate during aqueous‐deposited copolymerization initiated by ammonium persulfate

Monomer reactivity ratios of acrylonitrile/ammonium itaconate during aqueous‐deposited copolymerization initiated by ammonium persulfate were investigated. Kelen–Tudos method was used to examine the reactivity ratios. It was shown that the reactivity ratios were influenced by the conversions and temperatures of copolymerization. The reactivity ratios in aqueous‐deposited copolymerization system were similar to those in the solution polymerization system at polymerization conversions of less than 5% [reactivity ratio of acrylonitrile (r₁) 0.842 ± 0.02, reactivity ratio of ammonium itaconate (r₂) = 3.624 ± 0.02]. The reactivity ratio of AN rises and that of (NH₄)₂IA decreases, when the polymerization conversion increases till 13%. Aqueous‐deposited copolymerization initiated by AIBN was also studied. It was found that some polymers were formed in water phase and the monomers had different reactivity ratios by comparison with those initiated by ammonium persulfate. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 100: 4645–4648, 2006     

Radical polymerization of new functional monomer: methacryloyl isocyanate containing 3-chloro-1-propanol

A new functional monomer, methacryloyl isocyanate, containing 3-chloro-1-propanol (CPL-MAI), was prepared in a reaction of methacryloyl isocyanate (MAI) with 3-chloro-1-propanol (CPL) at low temperature and was characterized by IR, ¹H and ¹³C NMR spectra. Radical polymerization of CPL-MAI was studied in terms of the rate of polymerization, solvent effect, copolymerization, polymer modification and thermal properties. The rate of polymerization of CPL-MAI has been found to be smaller than that of styrene under the same conditions. Copolymerization of CPL-MAI (M₁) with styrene (M₂) in tetrahydrofuran (THF) was studied at 60°C. The monomer reactivity ratio was calculated to be r₁=0.26 and r₂=0.33 according to the method of Fineman–Ross. Poly(CPL-MAI) was easily modified by reacting with the sodium salt of carbazole leading to a displacement of 49% conversion. The TG curve for poly(CPL-MAI) is in two stages and shows two maxima peaks at 206 and 416°C.     

Effect of medium pH on the reactivity ratios in acrylamide acrylic acid copolymerization

The copolymerization reactivity ratios of acrylic acid and acrylamide are found at pH 5 and pH 2. Automatic continuous online monitoring of polymerization reactions (ACOMP) has been used for the first time to monitor the synthesis of polyelectrolytic copolymers. The composition drift during the reactions revealed that at pH 5, the acrylamide participates more in the copolymer, and at pH 2, the acrylic acid incorporates in the system at a higher ratio. The copolymerization data were analyzed by a recent error in variables (EVM) type calculation method developed for obtaining the reactivity ratios by on‐line monitoring and gave at pH 5 reactivity ratios r_Aam = 1.88 ± 0.17, r_Aac = 0.80 ± 0.07 and at pH 2 r_Aam = 0.16 ± 0.04, r_Aac = 0.88 ± 0.08. The results show that the reactivity ratios depend strongly on the pH of the medium. The effect of polyelectrolytic interactions on the reactivity ratios is discussed in detail. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 103: 968–974, 2007     

Study on monomer reactivity ratios of acrylonitrile/itaconic acid in aqueous deposited copolymerization system initiated by ammonium persulfate

A single water-soluble initiator-ammonium persulfate (APS), not containing alkali metal ions, was first utilized to initiate copolymerization of acrylonitrile (AN)/itaconic acid (IA) in aqueous deposited copolymerization system. Monomer reactivity ratios of this polymerization system were investigated using element analysis method and Q–e schemes. It was found that the monomer reactivity ratios of AN/IA calculated from Q–e schemes are 0.505 (r _AN) and 1.928 (r _IA), while the monomer reactivity ratios of AN/IA in aqueous deposited copolymerization system at 60 °C are 0.64 (r _AN) and 1.37 (r _IA) calculated from Kelen–Tüdõs method, 0.61 (r _AN) and 1.47 (r _IA) from Fineman–Ross method. The three pairs of monomer reactivity ratios are in good agreement. With the increase of the polymerization temperature, the monomer reactivity ratios of AN and IA approach to unity, indicating that the aqueous deposited copolymerization of AN/IA has a tendency to ideal copolymerization. At lower polymerization conversion, the monomer reactivity ratios of AN and IA have hardly any changes. When the polymerization conversion is more than 5%, the monomer reactivity ratio of AN increases, while that of IA decreases.     

Cyclodextrins in polymer synthesis: Influence of methylated β-cyclodextrin as host on the free radical copolymerization reactivity ratios of hydrophobic acrylates as guest monomers in aqueous medium

Summary Methylated (β-cyclodextrin (me-β-CD) was used to complex the hydrophobic monomers n-butyl acrylate (1), n-hexyl acrylate (2) and cyclohexyl acrylate (3) yielding the corresponding water soluble host/guest complexes 1a–3a. The complexes were copolymerized in water by free radical mechanism and the reactivity ratios were determined by measuring the monomer consumption by HPLC. The following reactivity ratios were found: copolymerization of 1a and 2a: r₁= 1.01 ± 0.01; r₂= 1.04 ± 0.01; copolymerization of 3a and 2a: r₁= 0.74; r₂= 1.28; copolymerization of 3a and 1a: r₁= 0.75 ± 0.04; r₂= 1.13 ± 0.01. In contrast to that, the copolymerization of the uncomplexed monomers 1–3 in organic medium (DMF/H₂O) leads to nearly ideal statistical copolymers in all cases. Received: 28 November 2000/Accepted: 12 January 2001     

Influence of the comonomers (styrene and methyl acrylate) on the rate of photocrosslinking of 4‐{[‐3‐(4‐hydroxybenzylidene)‐2‐oxocyclohexylidene]methyl}‐ phenyl acrylate

[2,6‐Bis(4‐hydroxybenzylidene)cyclohexanone] (HBC) was prepared by reacting cyclohexanone and p‐hydroxybenzaldehyde in the presence of acid catalyst. Acrylated derivative of HBC, 4‐{[‐3‐(4‐hydroxybenzylidene)‐2‐oxocyclohexylidene]methyl}phenyl acrylate (HBA), was prepared by reacting HBC with acryloyl chloride in the presence of triethylamine. Copolymers of HBA with styrene (S) and methyl acrylate (MA) of different feed compositions were carried out by solution polymerization technique by using benzoyl peroxide (BPO) under nitrogen atmosphere. All monomers and polymers were characterized by using IR and NMR techniques. Reactivity ratios of the monomers present in the polymer chain were evolved by using Finnman–Ross (FR), Kelen–Tudos (KT), and extended Kelen–Tudos (ex‐KT) methods. Average values of reactivity were achieved by the following three methods: r₁ (S) = 2.36 ± 0.45 and r₂ (HBA) = 0.8 ± 0.31 for poly(S‐co‐HBA); r₁ = 1.62 ± 0.06 (MA); and r₂ = 0.12 ± 0.07 (HBA) for poly(MA‐co‐HBA). The photocrosslinking property of the polymers was done by using UV absorption spectroscopic technique. The rate of photocrosslinking was enhanced compared to that of the homopolymers, when the HBA was copolymerized with S and MA. Thermal stability and molecular weights (M_w and M_n) were determined for the polymer samples. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 92: 2494–2503, 2004     

Über die Copolymerisation von Vinylacetat und Crotonaldehyd

In the study of the copolymerization of vinyl acetate (M₁) and croton aldehyde (M₂), it has been found that with the increasing content of the latter in the initial mixture, the reaction rate and the molecular weight of the copolymer strongly decrease. According to the proposed mechanism, the copolymerization proceeds with the chain transmitted through the monomer. The constants of copolymerization were established to be r₁ = 2.5 ± 0.3 and r₂ = 0 ± 0.2 and the probabilitics for the formation of the various sequences were calculated. The optimum conditions have been defined for the preparation of a copolymer with desired properties, which would serve as a carrier of medicines with prolonged action.     

Ring‐opening copolymerization of maleic anhydride with propylene oxide by double‐metal cyanide

Ring‐opening copolymerization of maleic anhydride (MA) with propylene oxide (PO) was successfully carried out by using double‐metal cyanide (DMC) based on Zn₃[Co(CN)₆]₂. The characteristics of the copolymerization are presented and discussed in this article. The structure of the copolymer was characterized with IR and ¹H‐NMR. Number‐average molecular weight (M_n) and molecular weight distribution (MWD) of the copolymer were measured by GPC. The results showed that DMC was a highly active catalyst for copolymerization of MA and PO, giving high yield at a low catalyst level of 80 mg/kg. The catalytic efficiency reached 10 kg polymer/g catalyst. Almost alternating copolymer was obtained when monomer charge molar ratio reached MA/PO ≥ 1. The copolymerization can be also carried out in many organic solvents; it was more favorable to be carried in polar solvents such as THF and acetone than in low‐polarity solvents such as diethyl ether and cyclohexane. The proper reaction temperature carried in the solvents was between 90 and 100 °C. The M_n was in the range of 2000–3000, and it was linear with the molar ratio of conversion monomer and DMC catalyst. The reactivity ratio of MA and PO in this reaction system was given by the extended Kelen–Tudos equation: η=[r₁+(r₂/α)]ξ?(r₂/α) at some high monomer conversion. The value of reactivity ratio r₁(MA) = 0 for MA cannot be polymerized itself by DMC catalyst, and r₂(PO) = 0.286. The kinetics of the copolymerization was studied. The results indicated that the copolymerization rate is first order with respect to monomer concentration. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 93: 1788–1792, 2004     

Copolymerization of 4-biphenyl methacrylate with glycidyl methacrylate: Synthesis, Characterization, thermal properties and determination of monomer reactivity ratios

Summary The methacrylic monomer, 4-biphenylmethacrylate (BPM) was synthesized by reacting 4-biphenyl phenol dissolved in ethyl methyl ketone (EMK) with methacryloyl chloride in presence of triethylamine as a catalyst. The copolymers of BPM with glycidyl methacrylate (GMA) were synthesized by free radical polymerization in EMK solution at 70±1 °C using benzoyl peroxide as a free radical initiator. The copolymerization behaviour was studied in a wide composition interval with the mole fractions of BPM ranging from 0.15 to 0.9 in the feed. The copolymers were characterized by FT-IR, ¹H-NMR and ¹³C-NMR spectroscopic techniques. The solubility was tested in various polar and non polar solvents. The molecular weight and polydispersity indices of the polymers were determined using gel permeation chromatography. The glass transition temperature of the copolymers increases with increase in BPM content. The thermogravimetric analysis of the polymers showed that the thermal stability of the copolymer increases with BPM content. The copolymer composition was determined using ¹H-NMR spectra. The monomer reactivity ratios were determined by the application of conventional linearization methods such as Fineman-Ross (r₁=0.392 ± 0.006, r₂ = 0.358 ± 0.007, Kelen-Tudos (r₁= 0.398 ± 0.004, r₂= 0.365 ± 0.013) and extended Kelen-Tudos methods (r₁= 0.394 ± 0.004, r₂= 0.352 ± 0.006).     

Radiation-induced copolymerization of α,β,β-trifluoroacrylonitrile with α-olefin

Homopolymerization and copolymerization of α,β,β-trifluoroacrylonitrile (FAN) with γ-olefins were carried out in bulk by γ-ray irradiation at 25°C. FAN gives very small quantities of brown and greasy low molecular weight polymer. Cyano groups in FAN polymer were found to be readily hydrolyzed to acid amide groups in the atmosphere. FAN was found to copolymerize with ethylene, propylene, and isobutylene via a radical mechanism to form equimolar copolymers in a wide range of monomer compositions. The polymerization rate increases linearly with FAN fraction in the monomer mixture. These copolymers are also hydrolyzed in the atmosphere, and the hydrolysis proceeds with more difficulty for the copolymer with higher α-olefin. The reactivity ratios r₁ (FAN) and r₂ (α-olefin) were determined to be 0.01 and 0.12 for the FAN/ethylene copolymerization and 0.01 and 0.07 for the FAN/propylene copolymerization. These results confirm that an alternating copolymerization takes place in the FAN/α-olefin system.     

Radical homopolymerization and copolymerizations of ring-methoxy substituted α-cyanostyrenes

Radical homopolymerization and copolymerizations of ring-methoxy substituted α-cyanostyrenes were studied using benzoyl peroxide and dimethyl 2,2′-azobisisobutylate at 60°C. It was found that the cyanostyrenes containing 2-methoxy cyanostyrene gave homopolymer in moderate yield and they were also copolymerized with vinyl monomers such as styrene and vinyl acetate. The relative reactivity of the cyanostyrenes towards a polystyryl radical (1/r₂) in the copolymerization of cyanostyrenes (M₁) and styrene (M₂) was correlated with the Hammett and Taft substituent constants of the methoxy groups and the ¹³C NMR chemical shift of the β-carbon of the cyanostyrenes. The enhancement of the radical polymerization reactivity by introducing a nitrile group in the captodative α-position of styrene was considered to be due to the suppression of the termination reaction and the activation of the propagation reaction. In addition, thermal properties such as glass transition and degradation temperatures of the cyanostyrene polymers obtained were also examined.     

A comparison of composition and sequence distribution of p(AM-MADQUAT) prepared by solution and inverse microemulsion polymerization

Acrylamide (AM)/2-(methacryloyloxy)ethyltrimethylammonium chloride (MADQUAT) copolymers were prepared by solution and inverse microemulsion polymerization using ammonium persulfate ((NH₄)₂S₂O₈)/sodium hydrosulfite (NaHSO₃) as redox initiator at 30 °C. The comonomer reactivity ratios, determined using the Kelen–Tudos (KT) method, were r _A = 0.30, r _M = 1.31 in solution and r _A = 0.63, r _M = 1.13 in the inverse microemulsion, respectively. The copolymer microstructure was deduced from the run number and the heterogeneity, based on reactivity ratios. It was found that copolymerization in the inverse microemulsion resulted in close to ideal copolymerization, giving almost random copolymers; copolymerization in solution resulted in some alternating copolymers. The copolymer compositions indicated that high-conversion samples obtained from the inverse microemulsion are much more homogeneous in composition compared with those obtained in solution. It was found that the composition distribution of the copolymer prepared by inverse microemulsion polymerization remained at approximately the feed ratio. The sequence distribution of the copolymer was predicted by first-order Markov statistical and Bernoulli statistical models, respectively. The results showed that the sequence distribution of the copolymer prepared by inverse microemulsion polymerization was almost random, which led to a wider cationic charge distribution and a microstructure that was coincident with the feed ratio.     

Monomer and radical reactivity ratios in 4‐vinylbenzenesulfonic acid sodium salt–acrylamide copolymerization in 0.1M NaCl solution

Reaction kinetics and composition of 4‐vinylbenzenesulfonic acid sodium salt (VB)–acrylamide (Aam) copolymerization in 0.1M NaCl solution are investigated. Data obtained by the automatic continuous monitoring of copolymerization system, up to 80% conversion, are analyzed by an “error‐in‐variables method” developed for obtaining the reactivity ratios by on‐line monitoring. Monomer reactivity ratios are found as r_Aam = 0.085 ± 0.020, r_VB = 2.0 ± 0.33. Although the terminal model describes the composition data well, it is seen to be inconsistent with the reaction rates. This discrepancy is attributed to implicit penultimate effects and using the recently developed calculation method, effective radical reactivity ratios are found as s_VB = 0.26 and s_Aam = 0.027, and both composition and rate data fit the implicit penultimate model extremely well. On‐line monitored data showed that in the reactions where the VB was completely consumed, the subsequent Aam homopolymerization was very rapid; thus, the reaction showed definitely two rate regimes, before and after VB depletion. Acrylamide take up rate also showed these two rate regimes. We conclude that low conversion results can be misleading and reactions must be monitored up to a high conversion for a robust control of composition and reaction kinetics. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

Non-ionizable Polyacrylic Hydrogels Sensitive to pH for Biomedical Applications

Hydrogels based on ethoxytriethyleneglycol monomethacrylate/methyl methacrylate (T/M) copolymers were prepared by free radical polymerization at 70°C in bulk with azobisisobutyronitrile as initiator. The reactivity ratios were calculated by Fineman–Ross (FR) and Kelen–Tudos (KT) linearization methods and by the non-linear least square method suggested by Tidwell and Mortimer (TM). The reactivity ratios obtained were r_T=0·17±0·03, r_M=0·70±0·01 (FR method); r_T=0·19±0·02, r_M=0·76±0·03 (KT method) and r_T=0·18; r_M= 0·75 (TM method). Microstructure was obtained in terms of the distribution of T- and M-centred triads. The swelling behaviour of the hydrogels was studied by immersion of the films in water and in buffered solutions at various pH values and it was analysed by comparison with that of poly(ethoxytriethyleneglycol monomethacrylate). It was observed that not only the average copolymer composition but also the distribution of monomeric sequences play an important role in the swelling behaviour. © 1997 SCI.