Photoconductive copolymers containing N-vinylcarbazole

The synthesis of N-vinylcarbazole (VCbz) copolymers in which electron-accepting groups are incorporated into the polymer chain is reported. The acceptors were introduced by appropriate reactions of VCbz–vinyl acetate or VCbz–acryloyl chloride copolymers and consisted of 3,5-dinitrobenzoyl, 2,4-dinitrophenyl acrylate, β-2,4-dinitrophenoxy propionate, and trichlorobenzoquinone units. The copolymer containing the 3,5-dinitrobenzoyl units required no chloranil as a dopant to be photoconductive, and in fact showed a slightly improved photoresponse relative to conventional poly VCbz doped with external chloranil.     

Molecular design of three-dimensional artificial extracellular matrix: Photosensitive polymers containing cell adhesive peptide

A photodimerizable monomer, methacrylic acid-(7-coumaroxy) ethyl ester, was synthesized and was copolymerized with a hydrophilic monomer (N,N-dimethylacrylamide) to obtain a water-soluble photosensitive polymer. Irradiation of the copolymer film and aqueous solution with a high-pressure mercury lamp resulted in highly hydrated gel. The gel yield was enhanced with the content of the photodimerizable group in the copolymer and the irradiation time. The degree of swelling of the gels decreased concomitantly. Incorporation of the well-known cell adhesive peptidyl ligand Arg-Gly-Asp-Ser(RGDS) into photosensitive copolymers attained a biologically active hydrophilic gel matrix upon UV light irradiation. Irradiation of a buffer solution of the latter copolymer premixed with smooth muscle cells entrapped the cells throughout the gel matrix. This indicates that the designed polymer and the resulting cell-incorporated hydrogel are biomimic to an extracellular matrix and to the media of the vascular wall, respectively. © 1993 John Wiley & Sons, Inc.     

Solvent Effects on the Absorption Spectrum of the Product and the Equilibrium Constant for the Proton Transfer Reaction from 1-Phenacylquinolinium Bromide to Amines

The equilibrium constants, K ₂, have been determined for the proton-transfer reactions of 1-phenacylquinolinium ion, PHQ⁺, with several amines {triethylamine (TEA), N,N,N′,N′-tetramethylethylenediamine (ED), N,N,N′, N′-tetramethylpropanediamine (PD), N,N,N′,N′-tetramethylbutanediamine (BD), and 1,8-bis(dimethylamino-naphthalene (DMAN)} in acetonitrile (AN), AN-tetrahydrofuran (THF) and AN-ethanol (EtOH) mixtures. The reaction was followed spectrophotometrically using a stopped-flow technique. The K ₂ value decreased for DMAN and increased for TEA with increasing vol-% of THF in AN-THF mixtures. The changes in the K ₂ value for ED, PD and BD changed in the order: ED, PD and BD from a pattern similar to TEA to a pattern similar to DMAN. The change in the K ₂ value for DMAN with increasing vol-% of THF in AN-THF mixtures was explained by the effect of polarity on the stability of P⁻Q⁺ (the deprotonated product of PHQ⁺). The effect of THF on the K ₂ value is consistent with that of the peak wavelength of the absorption spectrum of P⁻Q⁺. The change in the K ₂ value for TEA, ED, PD and BD depended on the structures of the protonated bases, one of the products for this reaction. The effect of EtOH on the K ₂ value for DMAN was examined in ternary EtOH-THF-AN mixtures that contain different amounts of EtOH and whose relative permittivities were adjusted to that of EtOH. The K ₂ value increased with increasing vol-% of EtOH because of the stabilization of P⁻Q⁺ upon the formation of the hydrogen-bonded complex with EtOH. The absorption spectrum of P⁻Q⁺ demonstrated a blue shift as the vol-% of EtOH increased.     

N-vinyl carbazole copolymers

The synthesis of N-vinyl carbazole (VCbz) copolymers, some of which contain electron-accepting groups, is described. The new copolymers are: copoly[N-vinyl carbazole-di(2-N-carbazylethyl)-fumarate](II); copoly(N-vinyl carbazole-vinyl-2,4-dinitrobenzene-sulfonate)(IV); copoly(N-vinyl carbazole-vinyl-2,4-dinitrobenzene-sulfenate)(V); copoly(n-butyl acrylate-t-butyl peracrylate)(VII); copoly(n-butyl acrylate-t-butyl acrylate-graft-N-vinyl carbazole)(VIII).     

Water-Soluble imide-amide copolymers. I. Preparation and characterization of poly [acrylamide-co-sodium N-(4-sulfophenyl) maleimide]

Sodium N-(4-sulfophenyl) maleimide (SPMI) and its saturated succinimide counterpart were first prepared according to established methods. Hydrolysis experiments on these monomers monitored by ¹H-NMR showed that although SPMI monomer was about 15% hydrolyzed in D₂O at 23°C in 24 h. Sodium N-(4-sulfophenyl) succinimide, which is similar in structure to the imide units in the copolymers, was only 1% hydrolyzed after 18 days at 23°C and 29% hydrolyzed after 18 days at 60°C. This indicated that the saturated imide rings in the copolymer might be sufficiently stable to hydrolysis for the copolymers to be useful. However, hydrolysis at high pH demonstrated that the imide rings would be rapidly saponified under alkaline conditions, destroying the structural rigidity that the intact rings might have provided in the copolymer chains. Sodium N-(4-sulfophenyl) maleimide (SPMI) was copolymerized with acrylamide in water at 30°C without cleavage of the imide ring. Water-soluble poly [acrylamide-co-sodium-N-(4-sulfophenyl) maleimide] (PAMSM) samples containing from 7.4 to 64 mol % imide were prepared. Photoacoustic FTIR and ¹³C-NMR spectra were used to confirm the structure of the copolymers obtained. Elemental analysis was used to determine the imide content of the copolymers, and from this composition data reactivity ratios were calculated for the two component monomers.     

Preparation of a thermally phase-separating copolymer,poly(N-isopropylacrylamide-co-N-acryloxysuccinimide), with a controlled number of active esters per polymer chain

N-isopropylacrylamide and N-acryloxysuccinimide have been copolymerized in various mixtures of terrahydrofuran and toluene using azobisisobutyronitrile as initiator. Polymerization has been conducted for 24 h at 50°C under a slightly positive pressure of nitrogen. The copolymers were assayed for active ester content by measuring the UV absorbance (259 nm) of N-hydroxysuccinimide anion, generated by reacting the copolymers with N-isopropylamine in dimethylformamide and dissolving the resulting mixture in 0.1M HEPES buffer, pH 7.5. The molecular weight and its distribution have been estimated by gel permeation chromatography. The active ester content was found to be equivalent to the comonomer feed ratio, and the major factor controlling the molecular weight was the ratio of tetrahydrofuran to toluene. Thus, the number of active esters per polymer chain could be controlled by adjustment of the comonomer feed ratio and the ratio of tetrahydrofuran to toluene. Monomer reactivity ratios for copolymerization of N-isopropylacrylamide with N-acryloxysuccinimide were also estimated. These copolymers are useful for immobilizing binding ligands such as antibodies for subsequent thermally induced precipitation immunoassays and bioseparation processes.     

Synthesis and characterization of sulfonated poly(benzoxazole ether ketone)s by direct copolymerization as novel polymers for proton-exchange membranes

A new series of sulfonated poly(benzoxazole ether ketone)s (SPAEKBO-X) were prepared by the aromatic nucleophilic polycondensation of 4,4′-(hexafluoroisopropylidene)-diphenol with 2,2′-bis[2-(4-fluorophenyl)benzoxazol-6-yl]hexafluoropropane and sodium 5,5′-carbonylbis-2-fluorobenzenesulfonate in various ratios. Fourier transform infrared and ¹H NMR were used to characterize the structures and sulfonic acid contents of the copolymers. The copolymers were soluble in N-methyl-2-pyrrolidinone, N,N-dimethylacetamide, and N,N-dimethylformamide and could form tough and flexible membranes. The protonated membranes were thermally stable up to 320 °C in air. The water uptake, hydrolytic and oxidative stability, and mechanical properties were evaluated. At 30–90 °C and 95% relative humidity, the proton conductivities of the membranes increased with the sulfonic acid content and temperature and almost reached that of Nafion 112. At 90–130 °C, without external humidification, the conductivities increased with the temperature and benzoxazole content and reached above 10⁻² S/cm. The SPAEKBO-X membranes, especially those with high benzoxazole compositions, possessed a large amount of strongly bound water (>50%). The experimental results indicate that SPAEKBO-X copolymers are promising for proton-exchange membranes in fuel cells, and their properties might be tailored by the adjustment of the copolymer composition for low temperatures and high humidity or for high temperatures and low humidity; they are especially promising for high-temperature applications. © 2007 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 45: 2273–2286, 2007     

Synthesis and properties of new block copolymers based on polydimethylsiloxane and tetraphenylethylene-containing polyimide

New polydimethylsiloxane (PDMS)-polyimide block copolymers were synthesized by the solution polycondensation of aminopropyl-terminated polydimethylsiloxane, 1,1-bis(4-aminophenyl)-2,2-diphenylethylene, and 3,3′,4,4′-benzophenonetetracarboxylic dithioanhydride in pyridine. New 1,3-bis(3-aminopropyl)tetramethyldisiloxane (BADS)-based random copolyimides were also prepared. The inherent viscosities of all the random and block copolyimides were in the range of 0.13–0.90 dL/g in N-methyl-2-pyrrolidone. These copolymers were soluble in N,N-dimethylacetamide, N-methyl-2-pyrrolidone, and m-cresol. All the BADS-based random copolymers and PDMS-containing copolymers with PDMS content above 42 wt % were soluble in tetrahydrofuran and chloroform. Transparent or somewhat cpaque films were prepared by casting from the reaction solutions. The BADS-based random copolyimides had one glass transition temperature (T_g) in the whole composition ranges, which showed single phase nature of the copolymers. On the other hand, the PDMS-polyimide block copolymers had double T_gS, indicating phase-separated morphology. The block copolymers containing PDMS content above 73 wt % behaved like a high temperature elastomer. © 1993 John Wiley & Sons, Inc.     

Synthesis and characterization of poly(N-acyl or N-aroyl ethylenimines) containing various pendant functional groups. I. Copolymers with pendant olefin groups

Decenyl (D) and heptyl (H) oxazolines were copolymerized in o-dichlorobenzene solvent using methyl 4-nitrobenzenesulfonate as an initiator. A series of decenyl/heptyl oxazolines random copolymers (or DH copolymers) with a total degree of polymerization of 100 and narrow molecular weight distribution were obtained. These copolymers are considered as the poly(N-acylethylenimine)s with allyl pendant groups randomly attached to the far end of their polymethylene, (SINGLE BOND)(CH₂)₇(SINGLE BOND), side chains. The polymers were characterized by NMR, FT–IR. Both DSC and x-ray diffractometer demonstrated that the polymers are highly crystalline. © 1996 John Wiley & Sons, Inc.     

Synthesis and polymerizations of methyl 3,3-difluorocyclobutene-1-carboxylate and methyl 3,3,4,4-tetrafluorocyclobutene-1-carboxylate

Two new monomers, methyl 3,3-difluorocyclobutene-1-carboxylate (MDFC) and methyl 3,3,4,4-tetrafluorocyclobutene-1-carboxylate (MTFC), were synthesized. Under free radical conditions, MDFC gave homopolymer; MTFC did not. Copolymerizations of these monomers showed them to behave as very electron-deficient monomers, MTFC more so than MDFC. MDFC copolymerized with various vinyl ethers and styrenes to give high yields of almost 1:1 copolymers. Acrylonitrile copolymerized in lower yield with less incorporation of MDFC; trimethylethylenetricarboxylate did not copolymerize. Bicyclobutane-1-carbonitrile copolymerized well. MTFC copolymerized with the very electron-rich monomers t-butyl vinyl ether and p-methoxystyrene, leading to alternating and nearly alternating copolymers, respectively, and even styrene tended to give almost 1:1 copolymers. Acrylonitrile gave only polyacrylonitrile, and trimethylethylenetricarboxylate did not react with MTFC under free radical conditions. The reaction of MTFC with the electron-rich monomers t-butyl vinyl ether and p-methoxystyrene occurred spontaneously via charge transfer complexes. Thermally, the copolymers were rather stable, those of MTFC more so than those of MDFC.     

Synthesis and characterization of poly(arylene ether)s containing 6‐(4‐hydroxyphenyl)pyridazin‐3(2H)‐one or 6‐(4‐hydroxyphenyl)pyridazine moieties

A series of novel soluble pyridazinone‐ or pyridazine‐containing poly(arylene ether)s were prepared by a polycondensation reaction. The pyridazinone monomer, 6‐(4‐hydroxyphenyl)pyridazin‐3(2H)‐one ( 1 ), was synthesized from the corresponding acetophenone and glyoxylic acid in a simple one‐pot reaction. The pyridazinone monomer was successfully copolymerized with bisphenol A (BPA) or 1,2‐dihydro‐4‐(4‐hydroxyphenyl)phthalazin‐1(2H)‐one (DHPZ) and bis(4‐fluorophenyl)sulfone to form high‐molecular‐weight polymers. The copolymers had inherent viscosities of 0.5–0.9 dL/g. The glass‐transition temperatures (T_g's) of the copolymers synthesized with BPA increased with increasing content of the pyridazinone monomer. The T_g's of the copolymers synthesized from DHPZ with different pyridazinone contents were similar to those of the two homopolymers. The homopolymers showed T_g's from 202 to 291 °C by differential scanning calorimetry. The 5% weight loss temperatures in nitrogen measured by thermogravimetric analysis were in the range of 411–500 °C. 4‐(6‐Chloropyridazin‐3‐yl)phenol ( 2 ) was synthesized from 1 via a simple one‐pot reaction. 2 was copolymerized with 4,4′‐isopropylidenediphenol and bis(4‐fluorophenyl)sulfone to form high‐T_g polymers. The copolymers with less than 80 mol % pyridazinone or chloropyridazine monomers were soluble in chlorinated solvents such as chloroform. The copolymers with higher pyridazinone contents and homopolymers were not soluble in chlorinated solvents but were still soluble in dipolar aprotic solvents such as N‐methylpyrrolidinone. The soluble polymers could be cast into flexible films from solution. © 2006 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 44: 3328–3335, 2006     

Synthesis and characterization of original alternated fluorinated copolymers bearing glycidyl carbonate side groups

A vinyl ether bearing a carbonate side group (2‐oxo‐1,3‐dioxolan‐4‐yl‐methyl vinyl ether, GCVE) was synthesized and copolymerized with various commercially available fluoroolefins [chlorotrifluoroethylene (CTFE), hexafluoropropylene (HFP), and perfluoromethyl vinyl ether (PMVE)] by radical copolymerization initiated by tert‐butyl peroxypivalate. Although HFP, PMVE, and vinyl ether do not homopolymerize under radical conditions, they copolymerized easily yielding alternating poly(GCVE‐alt‐F‐alkene) copolymers. These alternating structures were confirmed by elemental analysis as well as ¹H, ¹⁹F, and ¹³C NMR spectroscopy. All copolymers were obtained in good yield (73–85%), with molecular weights ranging from 3900 to 4600 g mol^?1 and polydispersities below 2.0. Their thermogravimetric analyses under air showed decomposition temperatures at 10% weight loss (T_d,10%) in the 284–330°C range. The HFP‐based copolymer exhibited a better thermal stability than those based on CTFE and PMVE. The glass transition temperatures were in the 15–65°C range. These original copolymers may find potential interest as polymer electrolytes in lithium ions batteries. © 2012 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2012     

Poly(N-acylethylenimine) copolymers containing pendant pentamethyldisiloxanyl groups. I. Synthesis

10-(Pentamethyl disiloxanyl) decyl oxazoline ( Si ) was synthesized. It was copolymerized with either undecyl ( U ) or nonyl ( N ) oxazolines using methyl 4-nitrobenzenesulfonate as initiator. Two series of random poly(N-acylethylenimine) copolymers, U/Si and N/Si , were synthesized over the whole composition range of Si monomer with a total degree of polymerization of about 100. Narrow molecular weight distributions were obtained. At a monomer to initator ratio of about 1060, the final degree of polymerization was 374 with a polydispersity index of 1.93. This shows the effect of chain transfer in this system.     

Synthesis of poly(vinylidene fluoride)‐b‐poly(styrene sulfonate) block copolymers by controlled radical polymerizations

Block copolymers based on poly(vinylidene fluoride), PVDF, and a series of poly(aromatic sulfonate) sequences were synthesized from controlled radical polymerizations (CRPs). According to the aromatic monomers, appropriate techniques of CRP were chosen: either iodine transfer polymerization (ITP) or atom transfer radical polymerization (ATRP) from PVDF‐I macromolecular chain transfer agents (CTAs) or PVDF‐CCl₃ macroinitiator, respectively. These precursors were produced either by ITP of VDF with C₆F₁₃I or by radical telomerization of VDF with chloroform, respectively. Poly(vinylidene fluoride)‐b‐poly(sodium styrene sulfonate), PVDF‐b‐PSSS, block copolymers were produced from both techniques via a direct polymerization of sodium styrene sulfonate (SSS) monomer or an indirect way with the use of styrene sulfonate ethyl ester (SSE) as a protected monomer. Although the reaction led to block copolymers, the kinetics of ITP of SSS showed that PVDF‐I macromolecular CTAs were not totally efficient because a limitation of the CTA consumption (56%) was observed. This was probably explained by both the low activity of the CTA (that contained inefficient PVDF‐CF₂CH₂? I) and a fast propagation rate of the monomer. That behavior was also noted in the ITP of SSE. On the other hand, ATRP of SSS initiated by PVDF‐CCl₃ was more controlled up to 50% of conversion leading to PVDF‐b‐PSSS block copolymer with an average number molar mass of 6000 g·mol^?1. © 2011 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2011     

Modifying the thermosensitivity of copolymers of sodium styrene sulfonate and<Emphasis Type="Italic"> N</Emphasis>-isopropylacrylamide with dodecyltrimethylammonium chloride

The interactions between copolymers of sodium styrene sulfonate (SSS) and N-isopropylacrylamide (NIPAM), anionic polyelectrolytes, and dodecyltrimethylammonium chloride (DTAC), a cationic surfactant, were studied in aqueous solutions of various ionic strengths. The copolymers were found to be thermoresponsive, showing a lower critical solution temperature (LCST). The influence of the polymer composition, the surfactant concentration, and the ionic strength on the LCST was studied. The surfactant was found to interact strongly with the polymer, forming mixed polymer-surfactant micelles. The critical aggregation concentration (cac) of the polymer-surfactant system was found from fluorescence spectroscopy using pyrene as a fluorescent probe. A strong dependence of the anionic polyelectrolyte-cationic surfactant interactions on the structure of the ionic comonomer was observed.     

Surface modification and adhesion characteristics of polycarbonate films after graft copolymerization

The surfaces of ozone-pretreated polycarbonate films were subjected to further modification by thermally induced graft copolymerization with acrylic acid (AAc), sodium salt of styrene sulfonic acid (NaSS), N,N-dimethylacrylamide (DMAA), N,N-(dimethylamino)ethyl methacrylate (DMAEMA) and 3-dimethyl(methacryloyl ethyl)-ammonium propanesulfonate (DMAPS) monomers. The structure and composition at the copolymer interface were studied by angle-resolved X-ray photoelectron spectroscopy (XPS). For polycarbonate films with a substantial amount of grafted polymer, the hydrophilic graft penetrates or becomes partially submerged beneath a thin surface layer of dense substrate chains. This microstructure was further supported by the water contact angle measurements. Adhesive-free adhesion studies revealed that the AAc, DMAA or DMAPS graft copolymerized polycarbonate film surface adhered strongly to another similarly modified surface (homo-interface) when brought into direct contact in the presence of water and subsequently dried. The development of the lap shear strength is dependent on the concentration of the surface graft, the microstructure of the grafted surface, the adhesion (drying) time, and the nature of the interfacial interaction. The simultaneous presence of chain entanglement and electrostatic interaction readily results in substantially enhanced adhesion strengths between two DMAPS graft copolymerized surfaces or between an AAc and a DMAA graft copolymerized surface (hetero-interface). XPS analyses of the delaminated surfaces suggest that failure occurred cohesively below the graft-substrate interface. © 1998 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 36: 357–366, 1998     

Preparation and characteristics of photocrosslinkable hydrophilic polymer having cinnamate moiety

The reaction of copolymer of N,N-dimethylacrylamide (DMAA) and bromoethyl methacrylate with potassium cinnamate produced water-soluble photosensitive polymers. Photosensitive polyDMAA films were irradiated with a 400 W high-pressure mercury lamp (λ > 280 nm) to produce crosslinked polymers, which were swollen in water. The degree of swelling was controlled by the irradiation time and content of cinnamate moieties in copolymers. Higher cinnamoylation and longer irradiation time resulted in higher yield of crosslinked polymers and less swellability. Partial degelation upon irradiation at λ ～ 254 nm was observed. The advantage of gelation via photodimerization over conventional chemical crosslinking methods is discussed in conjunction with biomedical applications. © 1992 John Wiley & Sons, Inc.     

Functional polymers. XXVII: 2[2-hydroxy-4-acryloxy(methacryloxy)phenyl]2H-benzotriazole: Monomers,polymers, and copolymers

2(2,4-Dihydroxyphenyl)2H-benzotriazole has been prepared in about 50% yield by condensation ofo-nitrobenzenediazonium chloride with resorcinol followed by reductive cyclization of the initially obtained azo compound with zinc and sodium hydroxide. The condensation of the diazonium salt had to be carried out under carefully controlled conditions and in acidic medium, otherwise bis-condensation occurred which, after reductive cyclization, yielded 2(2,4-dihydroxyphenyl)1,3-2H-dibenzotriazole. 2(2,4-Dihydroxyphenyl)2H-benzotriazole was allowed to react with acryloyl or methacryloyl chloride. Monoacylation in the 4-position occurred by interfacial acylation technique and 2[2-hydroxy-4-acryloxy (or 4-methacryloxy)]2H-benzotriazole was obtained in over 60% yield. The two monomers were homopolymerized and copolymerized with styrene, methyl methacrylate, andn-butyl acrylate to polymers of high molecular weight. Incorporation of 2[2-hydroxy-4-acryloxy (or 4-methacryloxy)]2H-benzotriazole into the copolymer was from 1 to 10 mol% of the comonomer mixture. The ultraviolet spectra of monomers, homo- and copolymers were also determined.This paper is dedicated to Professor Dr.Karl Schlögl on the occasion of his 60th birthday with our warmest wishes.     

Quinone copolymerization. I. Reactions of p-chloranil,p-benzoquinone,and 2,5-dimethyl-p-benzoquinone with vinyl monomers under free-radical initiation

The free-radical copolymerization reactions of p-chloranil, p-benzoquinone, and 2,5-di-methyl-p-benzoquinone with vinyl monomers were studied. Reactions of p-chloranil with styrene yielded copolymers of approximately 1:1 composition under a variety of reaction conditions. A copolymer containing a block of 1:1 of styrene:p-chloranil and a block of polystyrene was prepared. Several styrene-like monomers copolymerized with p-chloranil to yield copolymrs possessing considerable amounts of incorporated quinone. p-Benzoquinone copolymerized with 1,3-butadiene and 2-vinyl-pyridine to yield copolymers of significant molecular weights. Reactions of 2,5-dimethyl-p-benzoquinone with vinyl monomers did not yield any isolable polymeric products.     

Thermodynamic properties of copolymeric hydrogels based on 2-hydroxyethyl methacrylate and a zwitterionic methacrylate

The copolymerisation of 2-hydroxyethyl methacrylate and a zwitterionic methacrylate, namelyN,N-dimethyl-N-methacryloxyethyl-N-(3-sulphopropyl)-ammonium betaine (SPE), in the presence of a tetrafunctional crosslinker has been effected to 100% conversion by -irradiation. The resultant xerogels of different compositions were swollen to equilibrium in water to yield hydrogels. Volumetric swelling and compression-strain measurements were made over the temperature range 278–343 K. All these copolymers showed an increasing volumetric swelling with temperature, but the derived values of the partial molar enthalpy, entropy and Gibbs free energy of dilution showed certain differences which were interpreted on the basis of copolymer dyad distribution.