Synthesis, Characterization and Photophysical Properties of Rhenium Complex-Containing Polymer PS-b-PMAA(PNPh-Re)
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Two blcok copolymer PSt-b-PtBMA were synthesized by using ATRP method, in acid conditions, and further hydrolysis into amphiphilic copolymers PSt-b-PMAA; the PS-b-PMAA containing transition metal complex was obtained through PNPh-Re covacent-link to PS-b-PMAA chains, and the corresponding copolymers were charcterized by UV-vis and 1 H NMR.Keywords:
Characterization
The radical homopolymerization of styrene or copolymerization of styrene (S) with N-butyl maleimide (I) initiated by tetraethylthiuram disulfide was used to prepare macroinitiators having thiyl end groups. The S–I copolymers from the feeds containing 30–70 mol % I showed approximately alternating composition. The rate of copolymerization and molecular weights decreased with increasing maleimide derivative concentration in the feed; homopolymerization of I alone did not proceed. The macroinitiators served for synthesis of further S–I copolymers. Using polystyrene macroinitiator and the S–I copolymer with thiyl end groups in the polymerization of S–I mixture and styrene, respectively, the copolymers containing blocks of both polystyrene and alternating S–I copolymer were obtained. The copolymerization of S–I mixture initiated with the S–I copolymer bearing thiyl end groups led to the extension of macroinitiator chains by the blocks of alternating copolymer. The presence of the blocks in the polymer products was corroborated using elemental analysis, size exclusion chromatography, and differential scanning calorimetry. © 1998 John Wiley & Sons, Inc. J Appl Polym Sci 67: 755–762, 1998
Maleimide
Polystyrene
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The copolymerization and addition reaction of styrene (S) with N-phenylmaleimide (PMI), either neat or in xylene, have been found to proceed at 125°C in the presence of 2,2,6,6-tetramethylpiperidin-1-yloxy (TEMPO) radicals. TEMPO-terminated alternating S-PMI copolymers and comonomer adducts were obtained. The amounts of the low molecular weight compounds increased with the increasing content of PMI in the initial mixture. The reaction suggests formation of monofunctional unimolecular initiators. In the autopolymerization of neat comonomers, a mediating role of TEMPO was observed. The synthesized copolymers containing TEMPO end groups were used as macroinitiators to initiate polymerization of styrene. The molecular weight distributions of resulting poly(styrene-alt-N-phenylmaleimide)-block-polystyrene copolymers indicated the presence of both low molecular weight termination products and some copolymer precursor. The copolymers and comonomer adducts were characterized using the nitrogen analysis, size-exclusion chromatography (SEC), and NMR spectroscopy. © 2000 John Wiley & Sons, Inc. J Appl Polym Sci 76: 1093–1099, 2000
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Polystyrene
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Abstract Copolymerizations of combinations of 1.3‐dioxolane (DOL), styrene (St) and 3.3‐bis(chloromethyl) oxacyclobutane (BCMO), and terpolymerization of these monomers were investigated with the use of Et 3 OBF 4 as an initiator. A random copolymer of DOL and St with molecular weight as high as 3 × 10 5 was prepared. By utilizing a “living” nature of the polymerization of DOL by this initiator, a block copolymer (I) consisting of a DOL homopolymer block and a DOL‐St copolymer block was synthesized by two step copolymerization in which St monomer was added to a solution of “living” DOL polymer In a similar way, a block copolymer (II) was also prepared from DOL and BCMO: Terpolymerization of DOL, St and BCMO gave a resinous material, partly insoluble in hot benzene. At least the insoluble part was confirmed to be a terpolymer by elemental analysis and solubility tests. Two step terpolymerization by adding BCMO monomer into a solution of “living” DOL‐St copolymer yielded a benzene soluble product which was supposed to be a block copolymer (III) composed of a DOL‐St copolymer block and a DOL‐St‐BCMO terpolymer block: It is concluded by the successful preparation of terpolymers of DOL, St and BCMO that the latter two monomers which do not copolymerize with each other can be incorporated into a copolymer chain through the intermediary of DOL monomer.
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Abstract A series of polycarbonate copolymers were synthesized by the ring‐opening bulk polymerization of 2‐phenyl‐5,5‐bis(hydroxymethyl) trimethylene carbonate (PTC) and 5,5‐dimethyl trimethylene carbonate (DTC) with tin(II) 2‐ethylhexanoate and aluminum isopropoxide as initiators. The copolymers obtained were characterized by 1 H‐NMR, Fourier transform infrared, and ultraviolet. The influence of the molar ratio of the monomers, the initiators, and their concentrations, the reaction time, and the reaction temperature on the copolymerization was also studied. The copolymerization of monomers DTC and PTC was a nonideal copolymerization, and the copolymerization reactivity ratio of the monomer DTC was higher than that of PTC in the copolymerization process. In vitro release profiles of fluorouracil from the copolymers showed that the copolymer had a steady drug‐release rate and good controlled‐release property. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2008
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Polycarbonate
Trimethylene carbonate
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A novel nonconjugated N-vinyl monomer, N-vinylnaphthalimide (NVNPI), was copolymerized with various comonomers via reversible addition-fragmentation chain transfer process. Two different chain transfer agents (CTAs), O-ethyl-S-(1-ethoxycarbonyl) ethyldithiocarbonate (CTA 1) and benzyl 1-pyrrolecarbodithioate (CTA 2), were compared for these copolymerizations with 2,2′-azobis(isobutyronitrile) as an initiator. The structures of the resulting copolymers were characterized by 1H and 13C NMR spectroscopy, suggesting the sufficient incorporation of NVNPI, when methyl acrylate and N-isopropylacrylamide (NIPAAm) were used as comonomers. The copolymerization of NVNPI and NIPAAm using CTA 2 afforded well-defined copolymers with a predominantly alternating structure, controlled molecular weights (Mn = 2000−10700), and low molecular mass distributions (Mw/Mn = 1.21−1.29). Characteristic optical properties of the naphthalimide-containing copolymer were investigated by UV−vis and fluorescence spectroscopic methods.
Chain transfer
Raft
Methyl acrylate
Ethyl acrylate
Vinyl acetate
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In this paper the copolymerization of styrene and 4-vinylpyridine at 125°C in the presence of benzoyl peroxide (BPO) and 2,2,6,6-tetramethylpiperidine-N-oxyl (TEMPO) on the one hand and in the presence of a TEMPO-terminated polystyrene on the other is described. The molecular weights of the synthesized copolymers and block copolymers were found to increase with increasing conversion. Various nitroxides were used to prepare poly-[styrene-co-(4-vinylpyridine)] copolymers with BPO as the initiator. We found the use of 4-Oxo-TEMPO yielded high polymerization rates and high molecular weights. However, the polymerization in the presence of 4-NH2-TEMPO exhibits a slow rate and leads to copolymers with broad polydispersities. The influence of the other investigated nitroxides (4-OH- and 4-ACETAMIDO-TEMPO) on the copolymerization range between these both limits. The TEMPO-mediated copolymerizations of styrene and 4-vinylpyridine are slower than the comparable autopolymerization. However, the addition of an initiator which decomposes at the reaction temperature, such as dicumyl peroxide, leads to a considerable acceleration. By means of the Kelen-Tüdös method, the monomer reactivity ratios rS (styrene) and r4-VPy (4-vinylpyridine) were determined. The calculation for the TEMPO-mediated copolymerization at 125°C results in rS = 0.73 ± 0.09 and r4-VPy = 0.96 ± 0.15. The values for the spontaneous copolymerization at this temperatures are rS = 0.58 ± 0.04 and r4-VPy = 0.91 ± 0.05.
Polystyrene
Reactivity
Peroxide
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Abstract Kinetics of the anionic ring opening copolymerization of 2,4,6‐tris(3,3,3‐trifluoropropyl)‐2,4,6‐trimethylcyclotrisiloxane (F 3 ) with hexamethylcyclotrisiloxane (D 3 ) was studied in THF using BuLi as the initiator. The apparent reactivity ratios were estimated by computer simulation to r = 0.10 ± 0.02, r = 51.8 ± 5.5, which were used to predict the copolymer composition. As a result of so much different reactivities, simultaneous copolymerization leads to copolymers of blocky structure containing a narrow intermediate fragment with gradient distribution of siloxane units. Polymers having more uniform distribution of the trifluoropropyl groups along the chain were obtained by the semibatch process, adding F 3 to the polymerization of less reactive D 3 . The resulted copolymers were characterized by SEC chromatography, 29 Si NMR, DSC, DMA, and SAXS. Thermal and mechanical properties of the copolymers obtained by simultaneous copolymerization were similar to those of block copolymers. Only the copolymers obtained by semibatch method showed properties typical for gradient copolymers. © 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 47: 1204–1216, 2009
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Abstract 1H,1H,2H,2H ‐Perfluorooctyloxymethylstyrene (FS) was prepared and copolymerized with chloromethylstyrene (CMS). Conventional radical copolymerization of both these aromatic monomers led to poly(CMS‐ co ‐FS) random copolymers for which CMS was shown to be more reactive than the fluorinated comonomer. Their controlled radical copolymerization based on degenerative transfer, namely iodine transfer polymerization (ITP), led to various poly(CMS)‐ b ‐poly(FS) block copolymers. Molecular weights of poly(CMS‐ co ‐FS) copolymers reached 33,000 g mol −1 while those of poly(CMS)‐ b ‐ poly(FS) block copolymers were 22,000 g mol −1 . Their composition ranged from 18 to 61 mol.% in FS. These copolymers were modified via a cationization step, aiming at replacing the chlorine atom in CMS unit by a trimethylammonium group, leading to the formation of cationic sites. The resulting functionalized copolymers exhibited different solubilities. If both copolymerization techniques led to water‐insoluble copolymers, the block architecture enabled incorporating lower FS proportion, resulting in more cationic sites. © 2011 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2011
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Cationic polymerization
Atom-transfer radical-polymerization
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Abstract Polysiloxane diblock copolymers containing a pure polysiloxane backbone were prepared by the functionalization of poly(dimethylsiloxane)‐ b ‐poly(methylvinylsiloxane) copolymers. The copolymers were obtained by the sequential anionic copolymerization of either 1,3,5,7‐tetramethyl‐1,3,5,7‐tetravinylcyclotetrasiloxane or 1,3,5‐trimethyl‐1,3,5‐trivinylcyclotrisiloxane with hexamethylcyclotrisiloxane. The two vinyl monomers showed large differences in the propagation rates, but both could be used for the formation of polysiloxane block copolymers. Differences in the polymerization sequences were investigated and revealed that better control was obtained if the slower propagating monomer was polymerized first. The method permitted the synthesis of block copolymers with molecular weight distributions around 1.4 and lower and high block purities. The vinyl groups of the block copolymers were quantitatively and selectively functionalized by hydrosilation or epoxidation reactions. © 2002 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 40: 1539–1551, 2002
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