Statistical copolymers of methyl methacrylate and 2‐methacryloyloxyethyl ferrocenecarboxylate: Monomer reactivity ratios,thermal and electrochemical properties

Statistical copolymers of methyl methacrylate (MMA) with 2‐methacryloyloxyethyl ferrocenecarboxylate (MAEFC) were prepared by free radical polymerization. The reactivity ratios were estimated using the Fineman‐Ross, inverted Fineman‐Ross, Kelen‐Tüdos, and extended Kelen‐Tüdos graphical methods. Structural parameters of the copolymers were obtained by calculating the dyad monomer sequence fractions and the mean sequence length. The glass‐transition temperature (T_g) values of the copolymers were measured and examined by means of several theoretical equations, allowing the prediction of these T_g values. The thermal degradation behavior of the copolymers was also studied and compared with the respective homopolymers. Cyclic voltammetry was employed to study the electrochemical properties of the copolymers. © 2011 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2011     

Copolymers of 2,5‐bis[(4‐methoxyphenyl) oxycarbonyl]styrene with styrene and methyl methacrylate: Synthesis,monomer reactivity ratios,thermal properties,and liquid crystalline behavior

Copolymers of a liquid crystalline monomer, 2,5‐bis[(4‐methoxyphenyl)oxycarbonyl]styrene (MPCS), with St and MMA were prepared by free radical polymerization at low conversion in chlorobenzene with 2,2′‐azobisisobutyronitrile (AIBN) as initiator. The copolymers of poly(MPCS‐co‐St) and poly(MPCS‐co‐MMA) were characterized by ¹H NMR and GPC. The monomer reactivity ratios were determined by using the extended Kelen–Tudos (EKT) method. Structural parameters of the copolymers were obtained from the possibility statistics and monomer reactivity ratios. The influence of MPCS content in copolymers on the glass transition temperatures of copolymers was investigated by DSC. The thermal stabilities of the two copolymer systems increased with an increase of the molar fraction of MPCS in the copolymers. The liquid crystalline behavior of the copolymers was also investigated using DSC and POM. The results revealed that the copolymers with high MPCS molar contents exhibited liquid crystalline behaviors. © 2005 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 43: 2666–2674, 2005     

Antimicrobial activity on the copolymers of 2,4‐dichlorophenyl methacrylate with methyl methacrylate: Synthesis and characterization

Copolymers of monomers 2,4‐dichlorophenyl methacrylate (2,4‐DMA) and methyl methacrylate (MMA) were synthesized with different monomer feed ratios using toluene as a solvent and 2,2′‐azobisisobutyronitrile (AIBN) as an initiator at 70 °C. The copolymers were characterized by IR‐spectroscopy, and copolymer composition was determined with UV‐spectroscopy. The linearization method of Fineman–Ross was employed to obtain the monomer reactivity ratios. The molecular weights and polydispersity indexes were determined by gel permeation chromatography (GPC). Thermogravimetric analyses of polymers were carried out in nitrogen atmosphere. The homo‐ and copolymers were tested for their antimicrobial properties against selected microorganisms. © 2004 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 42: 5227–5234, 2004     

Copolymerization of N‐vinylcaprolactam and glycidyl methacrylate: Reactivity ratio and composition control

Free‐radical copolymerizations of N‐vinylcaprolactam (VCL) and glycidyl methacrylate (GMA) were investigated to synthesize temperature‐responsive reactive copolymers with minimized compositional heterogeneity. The average copolymer composition was determined by Fourier transform infrared and nuclear magnetic resonance techniques. The reactivity ratios for VCL and GMA were found to be 0.0365 ± 0.0009 and 6.44 ± 0.36 by the Fineman–Ross method and 0.039 ± 0.006 and 6.75 ± 0.29 by the Kelen–Tudos method, respectively. When prepared by batch polymerization, VCL–GMA copolymers had a highly heterogeneous composition and fractions of different solubilities in water. The use of a gradual feeding technique, which included the sequential addition of more reactive GMA monomer into the reaction, yielded copolymers with much more homogeneous composition. The produced copolymers with 0.9 and 0.11 fractional GMA contents preserved their temperature‐responsive properties and precipitated from aqueous solutions when the temperature exceeded 31 °C. The GMA units in the VCL–GMA copolymers were capable of reacting with amino end‐functionalized poly(ethylene oxide) at room temperature to produce poly(N‐vinylcaprolactam)–poly(ethylene oxide) graft copolymers. © 2005 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 44: 183–191, 2006     

Statistical copolymers of N‐vinylpyrrolidone and 2‐(dimethylamino)ethyl methacrylate via RAFT: Monomer reactivity ratios,thermal properties,and kinetics of thermal decomposition

Statistical copolymers of N‐vinylpyrrolidone (NVP) with 2‐(dimethylamino)ethyl methacrylate (DMAEMA) were prepared by Reversible Addition‐Fragmentation chain Transfer Polymerization (RAFT), employing three different RAFT agents: [(O‐ethylxanthyl)methyl]benzene, [1‐(O‐ethylxanthyl)ethyl]benzene, and O‐ethyl S‐(phthalimidylmethyl) xanthate. The reactivity ratios were estimated using the Fineman‐Ross, inverted Fineman‐Ross, Kelen‐Tüdos, and extended Kelen‐Tüdos graphical methods, along with the computer program COPOINT. Structural parameters of the copolymers were obtained by calculating the dyad sequence fractions and the mean sequence length. All the methods indicate that the DMAEMA reactivity ratio is much greater than the one of NVP, thus, the statistical copolymers are in fact pseudo‐diblocks. The glass‐transition temperature (T_g) values of the copolymers were measured by Differential Scanning Calorimetry. Furthermore, a systematic and detailed investigation has been done, on the thermal degradation of the copolymers compared with the respective homopolymers, by Thermogravimetric Analysis, within the framework of the Ozawa‐Flynn‐Wall and Kissinger methodologies. Apparently, the thermal stability of the copolymers is influenced by both monomers and by the structure of the thiocarbonylthio end groups due to the RAFT agents. © 2017 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2017 , 55, 3776–3787     

Kinetic Study of Radical Polymerization v. Determination of Reactivity Ratio in Copolymerization of Acrylonitrile and Itaconic Acid by 1H‐NMR

Many reports exist in the literature about the application of ¹H and ¹³C‐NMR techniques to analyze the copolymer structure and composition and also determination of reactivity ratios. In this work, on‐line ¹H‐NMR spectroscopy has been applied to identify reactivity ratios of itaconic acid and acrylonitrile in the solution phase (DMSO as the solvent) and in the presence of AIBN as the radical initiator. All the peaks corresponding to the existing protons were assigned quietly. Therefore, the kinetics of the copolymerization reaction was investigated by studying the variation of integral of two characteristic peaks regarding each monomer. The obtained data were used to find the reactivity ratios of acrylonitrile and itaconic acid by linear least‐squares methods such as Finemann‐Ross, inverted Finemann‐Ross, Mayo‐Lewis, Kelen‐Tudos, extended Kelen‐Tudos and Mao‐Huglin. In addition, a non‐linear least‐square method (Tidwell‐ Mortimer) was used at low conversions. Extended Kelen‐ Tudos and Mao‐Huglin were applied to determine reactivity ratio values at high conversions as well.     

The influence of comonomer (2‐hydroxyethyl acrylate) and keto group on photocrosslinking property of arylidene polymers

Two types of arylidene compounds were synthesized by reacting p‐hydroxybenzaldehyde with acetone [1,5‐bis(4‐hydroxyphenyl)penta‐1,4‐dien‐3‐one] (PBHP) and cyclohexanone [2,6‐bis(4‐hydroxybenzylidene)cyclohexanone] (HBC). 1,4‐Pentadien‐3‐one‐1‐p‐hydroxyphenyl‐5‐p‐phenyl methacrylate (PHPPMA) and 4‐{[‐3‐(4‐hydroxybenzylidene)‐2‐oxocyclohexylidene]methyl}phenyl acrylate (HBA) were prepared by reacting PBHP and HBC with methacryloyl chloride and acryloyl chloride in the presence of triethylamine, respectively. Copolymerization of different feed compositions of PHPPMA and HBA with 2‐hydroxyethyl acrylate (HEA) was carried out using a free‐radical solution polymerization technique in ethyl methyl ketone (MEK) using benzoyl peroxide (BPO). All the monomer and polymers were characterized by IR and NMR (¹H/¹³C) spectroscopic techniques. The reactivity ratio of the monomers were obtained using Fineman–Ross (FR), Kelen–Tudos (KT), and extended Kelen–Tudos (exKT) methods. The photocrosslinking properties of the polymers were done using a UV absorption spectroscopy technique. Homopolymers of both the arylidene polymers shows similar trend towards the rate of photocrosslinking. The rate of photocrosslinking was enhanced when the cyclohexanone based arylidene monomer was copolymerized with HEA. Thermal stability and molecular weights (M_w and M_n) of the polymers were determined. © 2004 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 42: 3433–3444, 2004     

Synthesis,characterization, thermal properties,and antimicrobial activity of 4‐chloro‐3‐methyl phenyl methacrylate/8‐quinolinyl methacrylate copolymers

4‐Chloro‐3‐methyl phenyl methacrylate (CMPM) and 8‐quinolinyl methacrylate (8‐QMA) were synthesized through the reaction of 4‐chloro‐3‐methyl phenol and 8‐hydroxy quinoline, respectively, with methacryloyl chloride. The homopolymers and copolymers were prepared by free‐radical polymerization with azobisisobutyronitrile as the initiator at 70 °C. Copolymers of CMPM and 8‐QMA of different compositions were prepared. The monomers were characterized with IR spectroscopy and ¹H NMR techniques. The copolymers were characterized with IR spectroscopy. UV spectroscopy was used to obtain the compositions of the copolymers. The monomer reactivity ratios were calculated with the Fineman–Ross method. The molecular weights and polydispersity values of the copolymers were determined with gel permeation chromatography. The thermal stability of the polymers was evaluated with thermogravimetric analysis under a nitrogen atmosphere. The homopolymers and copolymers were tested for their antimicrobial activity againstbacteria, fungi, and yeast. © 2004 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 43: 157–167, 2005     

Photocurable and thermally stable polymers based on 1,4‐pentadien‐3‐one‐1‐p‐hydroxyphenyl‐5‐p‐phenyl methacrylate: Copolymerization with ethyl acrylate

1,4‐Pentadien‐3‐one‐1,5‐bis(p‐hydroxyphenyl) (PBHP) was prepared by reacting p‐hydroxybenzaldehyde and acetone in the presence of an acid catalyst. 1,4‐Pentadiene‐3‐one‐1‐p‐hydroxyphenyl‐5‐p‐phenyl methacrylate (PHPPMA) monomer was prepared by reacting PBHP dissolved in ethyl methyl ketone (EMK) with methacryloyl chloride in the presence of triethylamine. A free‐radical solution polymerization technique was used for synthesizing homo‐ and copolymers of different feed compositions of PHPPMA and ethyl acrylate (EA) in EMK as a solvent with benzoyl peroxide as a free‐radical initiator at 70 ± 1 °C. All the polymers were characterized with IR and ¹H NMR techniques. The compositions of the copolymers were determined with the ¹H NMR technique. The copolymer reactivity ratios were evolved with Kelen–Tudos (EA = 1.25 and PHPPMA = 0.09) and extended Kelen–Tudos (EA = 1.30 and PHPPMA = 0.09) methods. Q (0.48) and e (1.68) values for the new monomer (PHPPMA) were calculated with the Alfrey–Price method. UV absorption spectra for poly(PHPPMA) showed two absorption bands at 302 and 315 nm. The photocrosslinking properties of the polymer samples were examined with the solvent method. Thermal analyses of the polymers were performed with the thermogravimetric‐differential thermogravimetric technique. First, the decomposition temperatures started for poly(PHPPMA), copoly(EA‐PHPPMA) (62:38), and copoly(EA‐PHPPMA) (41:59) were at 350, 410, and 417 °C, respectively. A gel permeation chromatographic method was used for determining the polymer molecular weights (weight‐average molecular weight: 2.67 × 10⁴ and number‐average molecular weight: 1.41 × 10⁴) and polydispersity index (1.89). The solubility of the monomer and the copolymers occurred at 30 °C with solvents having different polarities. © 2003 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 41: 1632–1640, 2003     

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).     

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     

Statistical copolymers of norbornene and 5‐vinyl‐2‐norbornene by a ditungsten complex mediated ring‐opening metathesis Polymerization: Synthesis,thermal properties,and kinetics of thermal decomposition

Statistical copolymers of norbornene (NBE) with 5‐vinyl‐2‐norbornene (VNBE) were prepared by ring‐opening metathesis polymerization, employing the triply bonded ditungsten complex Na[W₂(μ‐Cl)₃Cl₄(THF)₂].(THF)₃. NMR measurements revealed that the side vinyl groups of the VNBE monomer remain intact during the copolymerization reaction. The reactivity ratios were estimated using the Finemann–Ross (FR), the inverted FR, and the Kelen–Tüdos graphical methods. Structural parameters of the copolymers were obtained by calculating the dyad sequence fractions, which were derived using the monomer reactivity ratios. The glass transition temperatures, T_g, of the copolymers were measured by differential scanning calorimetry measurements and were examined in the frame of several theoretical equations allowing the prediction of these T_g values. The best fit was obtained using methods that take into account the monomer sequence distribution of the copolymers. Finally, the kinetics of the thermal decomposition of the copolymers was studied by thermogravimetric analysis in the frame of the Ozawa–Flynn–Wall and Kissinger methods. © 2013 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2013 , 51, 4835–4844     

Synthesis of a nanosize copolymer of 3,4‐ethylenedioxythiophene with diclofenac and characterization

Copolymer of 3,4‐ethylenedioxythiophene (EDOT) and diclofenac (DCF) was synthesized by chemical oxidation using FeCl₃ in neutral medium. The copolymer exhibited good solubility in many organic solvents. The UV‐vis spectrum of the copolymer revealed the presence of benzenoid and polaron or bipolaron state. Random distribution of the monomers in the copolymer was proposed based on the reactivity ratios of the monomers determined using Fineman‐Ross and Kelen‐Tudos methods. The rate of the copolymerization depended on the first power of each monomer. The FTIR spectrum showed the presence of hydrogen bonded N‐H, quinone type structure of thiophene ring and C‐Cl bond in the copolymer. Linear variation of anodic peak current at 560 mV in the cyclic voltammogram of copolymer thin film with scan rate indicated the adherence of electroactive copolymer. When the applied potential increased from ?600 to 1000 mV, the color of the copolymer changed from neutral yellow to brown and to violet medium showing multicolor electrochromic behaviour. XRD results revealed crystallite copolymer with size 87 nm. SEM analysis confirmed uniform crystalline nature of the copolymer. The TGA, DTA and DSC studies suggested good thermal stability of the copolymer. © 2007 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 45: 2787–2796, 2007     

Copolymer Formation Between Two N‐Substituted Anilines—Electrochemical and Spectroelectrochemical Studies

Abstract

Electrochemical polymerization of diphenylamine, DPA with N‐methyl aniline, NMA was performed using cyclic voltammetry in a 4?M sulfuric acid medium. The electrochemical parameters representing the polymer deposition showed a strong dependence on the molar concentration ratios of DPA or NMA in the feed. In situ spectroelectrochemical studies were performed during the electropolymerization with different molar concentration feed ratios of DPA. The results reveal the formation of intermediates together with DPA and NMA units. Derivative cyclic voltabsorptograms (DCVAs) were deduced at the wavelength of absorbance corresponding to the intermediates and explained with redox characteristics in cyclic voltammogram. Results from cyclic voltammetry and spectroelectrochemical studies favor copolymer formation between DPA and NMA. Copolymers were prepared for different molar concentrations feed ratios of DPA and the composition of the monomer units in the copolymers were determined. Reactivity ratios of DPA and NMA were deduced using Fineman–Ross and Kelen–Tudos methods and correlated with the results from cyclic voltammetry and spectroelectrochemical studies.     

Copper catalyzed atom transfer radical copolymerization of glycidyl methacrylate and 2‐ethylhexyl acrylate

This investigation reports the atom transfer radical copolymerization (ATRcP) of glycidyl methacrylate (GMA) and 2‐ethylhexyl acrylate (EHA). Poly(glycidyl methacrylate) (PGMA) has easily transformable pendant oxirane group and poly(2‐ethylhexyl acrylate) (PEHA) has very low T_g. They are the important components of coating and adhesive materials. Copolymerization of GMA and EHA was carried out in bulk and in toluene at 70 °C at different molar feed ratios using CuCl as catalyst in combination with 2,2′‐bypyridine (bpy) as well as N,N,N′,N″,N″‐pentamethyl diethylenetriamine (PMDETA) as ligand. The molecular weight (M_n) and the polydispersity index (PDI) of the polymers were determined by GPC analysis. The molar composition of the copolymers was determined by ¹H NMR analysis. The reactivity ratios of GMA (r₁) and EHA (r₂) were determined using Finemann‐Ross and Kelen‐Tudos linearization methods and those had been compared with the literature values for conventional free radical copolymerization. The thermal properties of the copolymers were studied by DSC and TGA analysis. © 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 47: 6526–6533, 2009     

Controlled radical copolymerization of β‐pinene and acrylonitrile

The feasibility of the radical copolymerization of β‐pinene and acrylonitrile was clarified for the first time. The monomer reactivity ratios evaluated by the Fineman–Ross method were r_β‐pinene = 0 and r_{acrylonitrile} = 0.66 in dichloroethane at 60 °C with AIBN, which indicated that the copolymerization was a simple alternating copolymerization. The addition of the Lewis acid Et₂AlCl increased the copolymerization rate and enhanced the incorporation of β‐pinene. The first example for the synthesis of an almost perfectly alternating copolymer of β‐pinene and acrylonitrile was achieved in the presence of Et₂AlCl. Furthermore, the possible controlled copolymerization of β‐pinene and acrylonitrile was then attempted via the reversible addition–fragmentation transfer (RAFT) technique. At a low β‐pinene/acrylonitrile feed ratio of 10/90 or 25/75, the copolymerization with 2‐cyanopropyl‐2‐yl dithiobenzoate as the transfer agent displayed the typical features of living polymerization. However, the living character could be observed only within certain monomer conversions. At higher monomer conversions, the copolymerizations deviated from the living behavior, probably because of the competitive degradative chain transfer of β‐pinene. The β‐pinene/acrylonitrile copolymers with a high alternation degree and controlled molecular weight were also obtained by the combination of the RAFT agent cumyl dithiobenzoate and Lewis acid Et₂AlCl. © 2006 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 44: 2376–2387, 2006     

Influence of the cocatalyst structure on the statistical copolymerization of methyl methacrylate with bulky methacrylates using the zirconocene complex Cp2ZrMe2

Statistical copolymers of methyl methacrylate with cyclohexyl and trimethylsilyloxy ethyl methacrylate were synthesized with two different catalytic systems based on the zirconocene complex Cp₂ZrMe₂. The reactivity ratios of methyl methacrylate and these methacrylates were calculated with the Finemann–Ross, inverted Finemann–Ross, and Kelen–Tüdos graphical methods. The structural parameters of these copolymers were estimated from the calculation of the dyad monomer sequence fractions. Two different borate cocatalysts were employed, and their effect on the copolymerization process is discussed. © 2005 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 43: 3305–3314, 2005     

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.     

An efficient way to tune grafting density of well‐defined copolymers via an unusual Br‐containing acrylate monomer

A series of well‐defined amphiphilic graft copolymers, containing hydrophilic poly(acrylic acid) backbone and hydrophobic poly(butyl acrylate) side chains, were synthesized by sequential reversible addition fragmentation chain transfer (RAFT) polymerization and atom transfer radical polymerization (ATRP) without any postpolymerization functionality modification followed by selective acidic hydrolysis of poly(tert‐butyl acrylate) backbone. tert‐Butyl 2‐((2‐bromopropanoyloxy)methyl)‐acrylate was first homopolymerized or copolymerized with tert‐butyl acrylate by RAFT in a controlled way to give ATRP‐initiation‐group‐containing homopolymers and copolymers with narrow molecular weight distributions (M_w/M_n < 1.20) and their reactivity ratios were determined by Fineman‐Ross and Kelen‐Tudos methods, respectively. The density of ATRP initiation group can be regulated by the feed ratio of the comonomers. Next, ATRP of butyl acrylate was directly initiated by these macroinitiators to synthesize well‐defined poly(tert‐butyl acrylate)‐g‐poly(butyl acrylate) graft copolymers with controlled grafting densities via the grafting‐from strategy. PtBA‐based backbone was selectively hydrolyzed in acidic environment without affecting PBA side chains to provide poly(acrylic acid)‐g‐poly(butyl acrylate) amphiphilic graft copolymers. Fluorescence probe technique was used to determine the critical micelle concentrations in aqueous media and micellar morphologies are found to be spheres visualized by TEM. © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 48: 2622–2630, 2010     

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.