N‐Bromosuccinimide as a thermal iniferter for radical polymerization

N‐Bromosuccinimide (NBS) was used as a thermal iniferter for the initiation of the bulk polymerizations of methyl methacrylate, methyl acrylate, and styrene. The polymerizations showed the characteristics of a living polymerization: both the yields and the molecular weights of the resultant polymers increased linearly as the reaction time increased. The molecular weight distributions of the polymers were 1.42–1.95 under the studied conditions. The resultant polymers could be used as macroiniferters to reinitiate the polymerization of the second monomer. The copolymers poly(methyl methacrylate)‐b‐polystyrene and polystyrene‐b‐poly(methyl methacrylate) were obtained and characterized. End‐group analysis of the resultant poly(methyl methacrylate), poly(methyl acrylate), and polystyrene confirmed that NBS behaved as a thermal iniferter. © 2005 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 43: 2567–2573, 2005     

Thermoresponsive copolymers of methacrylic acid and poly(ethylene glycol) methyl ether methacrylate

Copolymers of methacrylic acid (MAA) and poly(ethylene glycol) methyl ether methacrylate (PEGMA) were prepared and their cloud points in aqueous solution were studied as a function of comonomer ratio, solution pH, and presence of hydrophobic comonomers. Under acidic conditions, the cloud point falls below 0 °C for copolymers with between 25% to 60% ether content, because of the formation of hydrophobic H‐bonded ether–acid complexes. The cloud point also decreases with solution pH. For equivalent ether to acid ratios, the cloud point decreases with decreasing PEG chain length, because of the presence of a larger number of hydrophobic methyl and methacrylate groups. Similarly, the cloud point decreases upon incorporation of hydrophobic comonomers such as butyl, lauryl, or glycidyl methacrylates. © 2005 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 43: 6095–6104, 2005     

Properties of well‐defined alternating and random copolymers of methacrylates and styrene prepared by controlled/living radical polymerization

The physical properties of well‐defined alternating copolymers poly(methyl methacrylate‐alt‐styrene) and poly(n‐butyl methacrylate‐alt‐styrene), prepared by reversible addition–fragmentation chain transfer polymerization in the presence of Lewis acids, were investigated with differential scanning calorimetry, wide‐angle X‐ray scattering, and dynamic mechanical measurements. The properties were compared with those of random copolymers of the same overall composition and the corresponding homopolymers. Wide‐angle X‐ray scattering data showed that the alternating copolymers possessed a more regular comonomer sequence than the random copolymers. The thermomechanical properties of alternating copolymers and random copolymers were quite similar and typical for amorphous polymers, but in one of the cases studied the glass‐transition temperature for alternating copolymer was remarkably higher than for the random copolymer. © 2005 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 43: 3440–3446, 2005     

Poly(N‐phenylmaleimide‐co‐acrylic acid)–copper(II) and poly(N‐phenylmaleimide‐co‐acrylic acid)–cobalt(II) complexes: Synthesis,characterization, and thermal behavior

The free‐radical copolymerization of N‐phenylmaleimide (N‐PhMI) with acrylic acid was studied in the range of 25–75 mol % in the feed. The interactions of these copolymers with Cu(II) and Co(II) ions were investigated as a function of the pH and copolymer composition by the use of the ultrafiltration technique. The maximum retention capacity of the copolymers for Co(II) and Cu(II) ions varied from 200 to 250 mg/g and from 210 to 300 mg/g, respectively. The copolymers and polymer–metal complexes of divalent transition‐metal ions were characterized by elemental analysis, Fourier transform infrared, ¹H NMR spectroscopy, and cyclic voltammetry. The thermal behavior was investigated with differential scanning calorimetry (DSC) and thermogravimetry (TG). The TG and DSC measurements showed an increase in the glass‐transition temperature (T_g) and the thermal stability with an increase in the N‐PhMI concentration in the copolymers. T_g of poly(N‐PhMI‐co‐AA) with copolymer composition 46.5:53.5 mol % was found at 251 °C, and it decreased when the complexes of Co(II) and Cu(II) at pHs 3–7 were formed. © 2005 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 43: 4933–4941, 2005     

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     

Properties of polystyrene and polymethyl methacrylate copolymers of polyhedral oligomeric silsesquioxanes: A molecular dynamics study

Molecular dynamics simulations were carried out on copolymers of both styrene and methyl methacrylate with polyhedral oligomeric silsesquioxane (POSS) derivatives to identify the origin of the property changes imparted upon the chemical incorporation of POSS. Simulations were carried out on these hybrid copolymers and the parent homopolymers to elucidate the effect of the T₈, T₁₀, and T₁₂ POSS cages. These POSS comonomers were derivatized with a single polymerizable function and 7, 9, and 11 nonpolymerizable hydrocarbon moieties, respectively. Glass transition temperatures (T_g) were computed from specific volume versus temperature plots. The packing of POSS units around the polymer backbone was analyzed via their radial distribution functions. The effect of POSS on polymer motion was analyzed through the mean square displacement function. The improvements in the elastic moduli upon incorporation of POSS were computed by employing the static deformation method. © 2005 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 44: 234–248, 2006     

Side‐chain crystallization behavior of graft copolymers consisting of amorphous main chain and crystalline side chains: Poly(methyl methacrylate)‐graft‐poly(ethylene glycol) and poly(methyl acrylate)‐graft‐poly(ethylene glycol)

Graft copolymers consisting of amorphous main chain, poly(methyl methacrylate) (PMMA), or poly(methyl acrylate) (PMAc), and crystalline side chains, poly(ethylene glycol) (PEG), have been prepared by copolymerization of PEG macromonomers with methyl methacrylate or methyl acrylate (MMAx or MACx, respectively). Because of the compatibility of PMMA/PEG and PMAc/PEG, from small‐angle X‐ray scattering results, the main and side chains in graft copolymers were suggested to be homogeneous in the molten state. Differential scanning calorimetry (DSC) cooling scans revealed that PEG side chains for graft copolymers with large PEG fractions were crystallized when the sample was cooled, with a cooling rate of 10 °C/min. The spherulite pattern observed by a polarized optical microscope suggested the growth of PEG crystalline lamellae. Crystallization of PEG in MMAx was more restrained than in MACx. From these results, we have concluded that the crystallization behavior of the grafted side chains is strongly influenced by the glass transition of a homogeneously molten sample as well as dilution of the crystallizable chains. Domain spacings for isothermally crystallized graft copolymers were described by interdigitating chain packing in crystalline–amorphous lamellar structure. © 2004 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 43: 79–86, 2005     

Syntheses of graft and star copolymers possessing polyolefin branches by using polyolefin macromonomer

Graft and star copolymers having poly(methacrylate) backbone and ethylene–propylene random copolymer (EPR) branches were successfully synthesized by radical copolymerization of an EPR macromonomer with methyl methacrylate (MMA). EPR macromonomers were prepared by sequential functionalization of vinylidene chain‐end group in EPR via hydroalumination, oxidation, and esterification reactions. Their copolymerizations with MMA were carried out with monofunctional and tetrafunctional initiators by atom transfer radical polymerization (ATRP). Gel‐permeation chromatography and NMR analyses confirmed that poly(methyl methacrylate) (PMMA)‐g‐EPR graft copolymers and four‐arm (PMMA‐g‐EPR) star copolymers could be synthesized by controlling EPR contents in a range of 8.6–38.1 wt % and EPR branch numbers in a range of 1–14 branches. Transmission electron microscopy of these copolymers demonstrated well‐dispersed morphologies between PMMA and EPR, which could be controlled by the dispersion of both segments in the range between 10 nm and less than 1 nm. Moreover, the differentiated thermal properties of these copolymers were demonstrated by differential scanning calorimetry analysis. On the other hand, the copolymerization of EPR macromonomer with MMA by conventional free radical polymerization with 2,2′‐azobis(isobutyronitrile) also gave PMMA‐g‐EPR graft copolymers. However, their morphology and thermal property remarkably differed from those of the graft copolymers obtained by ATRP. © 2005 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 43: 5103–5118, 2005     

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     

Characterization and degradation of the poly(methylphenylsiloxane)–poly(methyl methacrylate) graft copolymer

Poly(methylphenylsiloxane)–poly(methyl methacrylate) graft copolymers (PSXE-g-PMMA) were prepared by condensation reaction of poly(methylphenylsiloxane)-containing epoxy resin (PSXE) with carboxyl-terminated poly(methyl methacrylate) (PMMA), and they were characterized by gel permeation chromatography (GPC), infrared (IR), and ²⁹Si and ¹³C nuclear magnetic resonance (NMR). The microstructure of the PSXE-g-PMMA graft copolymer was investigated by proton spin–spin relaxation T₂ measurements. The thermal stability and apparent activation energy for thermal degradation of these copolymers were studied by thermogravimetry and compared with unmodified PMMA. The incorporation of poly(methylphenylsiloxane) segments in graft copolymers improved thermal stability of PMMA and enhanced the activation energy for thermal degradation of PMMA. © 1998 John Wiley & Sons, Inc. J. Polym. Sci. A Polym. Chem. 36: 2521–2530, 1998     

Synthesis and polymerization studies of N-cyanomethanimine monomers

New imine monomers containing C-aryl and N-cyano substituents were synthesized and polymerized by both radical and anionic initiation. Homopolymerization yielded low molecular weight polymers (M_n < 2100). Higher yields were obtained with anionic initiation rather than radical initiation. Radical initiated copolymerization with p-methoxystyrene gave low yields of low molecular weight copolymers. Radical initiated copolymerization with methyl acrylate gave copolymers of 15,000–,32,000 molecular weight in moderate yields, but with rather low incorporation of the imine monomer. The C-substituent affected the anionic and free radical reactivity similarly. © 1997 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 35 : 2703–2710, 1997     

Covalent stabilization of nanostructures: Robust block copolymer templates from novel thermoreactive systems

Structurally robust block copolymer templates with feature sizes of approximately 10 nm were prepared from functionalized poly(methyl methacrylate)‐b‐polystyrene block copolymers. By the inclusion of benzocyclobutene crosslinking groups in the polystyrene block, the covalent stabilization of thin films to both thermal treatment and solvent exposure became possible. In addition, the crosslinking of the poly(styrene‐benzocyclobutene) domains at 220 °C, followed by the removal of poly(methyl methacrylate), provided a robust, crosslinked nanostructure with greater processing and fabrication potential. © 2005 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 43: 1028–1037, 2005     

Densely grafting copolymers of ethyl cellulose through atom transfer radical polymerization

Densely grafting copolymers of ethyl cellulose with polystyrene and poly(methyl methacrylate) were synthesized through atom transfer radical polymerization (ATRP). First, the residual hydroxyl groups on the ethyl cellulose reacted with 2‐bromoisobutyrylbromide to yield 2‐bromoisobutyryloxy groups, known to be an efficient initiator for ATRP. Subsequently, the functional ethyl cellulose was used as a macroinitiator in the ATRP of methyl methacrylate and styrene in toluene in conjunction with CuBr/N,N,N′,N″,N″‐pentamethyldiethylenetriamine as a catalyst system. The molecular weight of the graft copolymers increased without any trace of the macroinitiator, and the polydispersity was narrow. The molecular weight of the side chains increased with the monomer conversion. A kinetic study indicated that the polymerization was first‐order. The morphology of the densely grafted copolymer in solution was characterized through laser light scattering. The individual densely grafted copolymer molecules were observed through atomic force microscopy, which confirmed the synthesis of the densely grafted copolymer. © 2005 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 43: 4099–4108, 2005     

Solid acid clay mediated copolymerization of methyl acrylate and 1‐octene: 2D NMR substantiation of predominant alternating comonomer sequence

Montmorillionite K10 powder presence during radically initiated copolymerization of methyl acrylate (M) and 1‐octene (O) gave copolymers with higher incorporation of alkene unit. Highly viscous and transparent copolymers showed alternation irrespective of the copolymer composition. Increasing the amount of K10 powder increased the total percentage conversion, as well as 1‐octene incorporation. The monomodal curves obtained in gel permeation chromatography (GPC) substantiated that true copolymers were formed. The alternation in the copolymers was authenticated through Heteronuclear Multiple Quantum Correlation (HMQC) experiments in conjugation with Total Correlated Spectroscopy (TOCSY). © 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 47: 2156–2162, 2009     

Optimization of the synthesis of poly(octadecyl acrylate) by atom transfer radical polymerization and the preparation of all comblike amphiphilic diblock copolymers

The atom transfer radical polymerization of octadecyl acrylate (ODA) has been investigated and optimized to produce polymers with predetermined molecular weights and narrow polydispersities (<1.2). The poor solubility of the catalytic system formed with conventional ligands such as the N‐(n‐propyl)‐2‐pyridylmethanimine and 2,2′‐bipyridine with Cu(I)Br in nonpolar reaction conditions gave poor control over molecular weight characteristics in ODA polymerizations. The use of N‐(n‐octyl)‐2‐pyridylmethanimine in combination with Cu(I)Br yielded a more soluble catalyst that improved control over the polymerization. The products from the polymerizations were further improved when an initiator, octadecyl 2‐bromo‐2‐methyl‐propanoate, similar in structure to the monomer, was used. Together, these modifications produced polymerizations that showed true controlled character as well as products with predetermined molecular weights and narrow polydispersities. Diblock copolymers of PODA were prepared with methyl methacrylate (MMA) and olig(oethylene glycol) methyl ether methacrylate (OEGMA). The PODA‐block‐POEGMA copolymers are the first examples of all comblike amphiphilic block copolymers. One of PODA‐block‐POEGMA copolymer samples has been shown to self‐assemble as micelles in a dilute aqueous solution. © 2005 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 43: 1129–1143, 2005     

Synthesis of a novel liquid crystal rod–coil star block copolymer consisting of poly(methyl methacrylate) and poly{2,5‐bis[(4‐methoxy‐phenyl)oxycarbonyl] styrene} via atom transfer radical polymerization

A bromine capped star‐shaped poly(methyl methacrylate) (S‐PMMA‐Br) was synthesized with CuBr/sparteine/PT‐Br as a catalyst and initiator to polymerize methyl methacrylate (MMA) according to atom transfer radical polymerization (ATRP). Then, with S‐PMMA‐Br as a macroinitiator, a series of new liquid crystal rod–coil star block copolymers with different molecular weights and low polydispersity were obtained by this method. The block architecture {coil‐conformation of the MMA segment and rigid‐rod conformation of 2,5‐bis[(4‐methoxyphenyl)oxycarbonyl] styrene segment} of the four‐armed rod–coil star block copolymers were characterized by ¹H NMR. The liquid‐crystalline behavior of these copolymers was studied by differential scanning calorimetry and polarized optical microscopy. We found that the liquid‐crystalline behavior depends on the molecular weight of the rigid segment; only the four‐armed rod–coil star block copolymers with each arm's M_n,_GPC of the rigid block beyond 0.91 × 10⁴ g/mol could form liquid‐crystalline phases above the glass‐transition temperature of the rigid block. © 2005 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 43: 733–741, 2005     

Effect of incorporated CdS nanoparticles on the crystallinity and morphology of poly(styrene‐b‐ethylene oxide) diblock copolymers

Surface‐modified CdS nanoparticles selectively dispersed in hexagonally packed poly(ethylene oxide) (PEO) cylinders of poly(styrene‐b‐ethylene oxide) (PSEO) block copolymers were prepared. The photoluminescence and ultraviolet–visible characteristics of the presynthesized CdS nanoparticles in N,N‐dimethylformamide and in PEO domains of the PSEO block copolymers were determined. Because of strong interactions between the CdS nanoparticles and PEO chains, as shown by Fourier transform infrared spectroscopy, the incorporation of the CdS nanoparticles prevented the PEO cylinders from properly crystallizing; this was confirmed by differential scanning calorimetry and wide‐angle X‐ray diffraction measurements. The intercylinder distance between the swollen and reduced‐crystallinity CdS/PEO cylinders in turn increased, as confirmed by small‐angle X‐ray scattering and transmission electron microscopy. At a high CdS concentration (43 wt % or 8.3 vol % with respect to PEO), however, the hexagonally packed cylindrical nanostructure of the PSEO diblock copolymers was destroyed. © 2005 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 43: 1220–1229, 2005     

Block copolymers of acrylic acid and butyl acrylate prepared by reversible addition–fragmentation chain transfer polymerization: Synthesis,characterization, and use in emulsion polymerization

Amphiphilic block copolymers of poly(acrylic acid‐b‐butyl acrylate) were prepared by reversible addition–fragmentation chain transfer polymerization in a one‐pot reaction. These copolymers were characterized by NMR, static and dynamic light scattering, tensiometry, and size exclusion chromatography. The aggregation characteristics of the copolymers corresponded to those theoretically predicted for a star micelle. In a butyl acrylate and methyl methacrylate emulsion polymerization, low amounts of these copolymers could stabilize latices with solid contents up to 50%. © 2003 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 41: 684–698, 2003     

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     

Automated parallel anionic polymerizations: Enhancing the possibilities of a widely used technique in polymer synthesis

Anionic polymerization techniques have been implemented successfully in a commercial automated synthesizer. The main problems for a successful adaptation of the experimental technique in the automated synthesizer are addressed, as well as some simple potential applications, such as the anionic polymerization of styrene, isoprene, and methyl methacrylate. The obtained results were reproducible and in concordance with literature knowledge. The apparent rate constant of the anionic polymerization of styrene in cyclohexane initiated by sec‐butyllithium could be determined at two different concentrations of the monomer and initiator in a temperature range of 10–60 °C. All the synthesis and characterization experiments of the polymers were performed within a short time period. Moreover, the syntheses of poly(styrene‐b‐isoprene) and poly(styrene‐b‐methyl methacrylate) block copolymers were also successfully carried out within the automated synthesizer. © 2005 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 43: 4151–4160, 2005