Synthesis,photopolymerization, and adhesive properties of new bisphosphonic acid monomers for dental application

Four new monomers, 3‐(N‐methylacrylamido)propylidenebisphosphonic acid, 3‐(N‐propyl‐acrylamido)propylidenebisphosphonic acid, 3‐(N‐hexylacrylamido)propylidenebisphosphonic acid, and 3‐(N‐octylacrylamido)propylidenebisphosphonic acid, have been synthesized in good yields and fully characterized by ¹H, ¹³C, ³¹P NMR, and HRMS. The copolymerization of these monomers with N,N′‐diethyl‐1,3‐bis(acrylamido)propane (DEBAAP) has been investigated with differential scanning calorimetry. These mixtures show a higher reactivity than DEBAAP. New self‐etch dental primers, based on these acrylamide monomers, have been formulated. Dentin shear bond strength measurements have shown that primers based on these bisphosphonic acids assure a strong bond between the tooth substance and a dental composite. © 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 47: 5258–5271, 2009     

Synthesis and stability study of dental monomers containing methacrylamidoethyl phosphonic acids

Three new dental monomers containing methacrylamidoethyl phosphonic acids were synthesized. The structures of the synthesized monomers were determined with electrospray mass spectrometry (ESMS), Fourier transform infrared, and NMR. The hydrolytic stabilities of the synthesized monomers and a commercial monomer, 2‐methacryloyloxyethyl phosphoric acid (MEP; used as a control), were studied with flow injection (FI)/ESMS, ¹H NMR, and ³¹P NMR analysis of a CD₃OD/D₂O (4:1 v/v) solution of each monomer before and after storage at 60 °C for 2 months. The ¹H NMR and ³¹P NMR chemical shifts of the monomers 2‐methacrylamidoethylphosphonic acid ( I ) and N,N′‐[4,4′‐(propane‐2,2‐diyl)‐bis(phenoxy‐2‐hydroxypropyl)]‐bis(2‐methacrylamidoethylphosphonic acid) ( II ) showed little change after storage at 60 °C for 2 months, but those of MEP changed significantly. FI/ESMS also showed that MEP was nearly completely decomposed, whereas monomers I and II remained largely intact. MEP could react with H₂ZrF₆ to form ternary zirconium fluoride complexes that were partially soluble in methanol, but all the monomers containing phosphonic acids formed precipitates. This study demonstrates that ESMS is a more sensitive and effective method than NMR for studying the hydrolytic stability or degradation of dental monomers. The new monomers containing methacrylamidoethyl phosphonic acids have higher hydrolytic stability than methacrylate phosphate monomers and may be used in dental bonding agents and other dental materials. © 2006 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 45: 99–110, 2007     

Monomers for adhesive polymers. XV. Synthesis,photopolymerization, and adhesive properties of polymerizable β‐ketophosphonic acids

The novel polymerizable β‐ketophosphonic acids 4 , 8 , 10 , and 16 as well as the 9‐(methacryloyloxy)‐nonylphosphonic acid 20 were synthesized in four to eight steps. They were characterized by ¹H NMR, ¹³C NMR, and ³¹P NMR spectroscopy and by high‐resolution mass spectra. The free‐radical polymerization of 4 , 8 , 10 , and 16 was carried out in a water/ethanol solution, using 2,2′‐azo(2‐methylpropionamidine)dihydrochloride as initiator. To evaluate the reactivity of the acidic monomers 4 , 8 , 10 , 16 , and 20 , their photopolymerization behavior was investigated by photodifferential scanning calorimeter. Copolymerizations with 2‐hydroxyethyl methacrylate, glycol dimethacrylate, and N,N′‐diethyl‐1,3‐bis‐(acrylamido)propane were studied. The homopolymerization of the corresponding β‐ketophosphonates and their copolymerization with hydroxyethyl methacrylate were also carried out. Self‐etch adhesives based on the β‐ketophosphonic acids 4 , 8 , 10 , and 16 were able to provide high shear bond strengths (SBSs) of dimethacrylate‐based composite to dentin and enamel. The β‐ketophosphonic acid 8 was also shown to exhibit significantly better adhesive properties than the corresponding phosphonic acid 20 . Indeed, the presence of the carbonyl moiety in the β‐position of the phosphonic acid group led to a strong improvement of the composite SBS to dentin and enamel. © 2014 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2014 , 52, 3550–3563     

Synthesis,photopolymerization, and adhesive properties of hydrolytically stable phosphonic acid‐containing (meth)acrylamides

Three novel dental monomers containing phosphonic acid groups ( 1a and 2a , based on diethyl amino(phenyl)methylphosphonate and 3a based on diethyl 1‐aminoheptylphosphonate) were synthesized in two steps: the reaction of α‐aminophosphonates with acryloyl chloride (for monomers 1a and 3a ) or methacryloyl chloride (for 2a ) to give monomers with phosphonate groups, and the hydrolysis of phosphonate groups by using trimethyl silylbromide. Their (and the intermediates') structures were confirmed by FTIR, ¹H, ¹³C, and ³¹P NMR spectroscopy. All the monomers dissolve well in water (1<pH<2) and are hydrolytically stable. Their homo‐ and copolymerizations with 2‐hydroxyethyl methacrylate (HEMA) and HEMA/glycerol dimethacrylate were investigated with photo‐DSC. Thermal polymerization of the new monomers in water or in ethanol/water solution was investigated, giving polymers in good yields. X‐ray diffraction results showed only dicalcium phosphate dehydrate formation upon interaction of 1a ‐ 3a with hydroxyapatite indicating its strong decalcification and that monomer‐Ca salts are highly soluble. Some results were also compared to those with a bisphosphonic acid‐containing methacrylamide ( 4a ) previously reported; and the influence of monomer structure on polymerization/adhesive properties is discussed. These properties, especially hydrolytic stability and good rates of polymerization, make these new monomers suitable candidates as components of dental adhesive mixtures. © 2013 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2014 , 52, 511–522     

Synthesis and evaluation of new dental monomers with both phosphonic and carboxylic acid functional groups

Novel dental monomers containing both phosphonic and carboxylic acid functional groups were prepared. The monomers were based on t‐butyl α‐bromomethacrylate (t‐BuBMA) and synthesized in three steps: The reaction of o‐hydroxyaryl phosphonates [diethyl (2‐hydroxyphenyl) phosphonate, tetraethyl (2,5‐dihydroxy‐1,4‐phenylene) diphosphonate and tetraethyl 5,5′‐(propane‐2,2‐diyl)bis(2‐hydroxy‐5,1‐ phenylene) diphosphonate] with t‐BuBMA, the hydrolysis of phosphonate groups to phosphonic acid using trimethyl silylbromide, and the hydrolysis of the t‐butyl groups to carboxylic acid with trifluoroacetic acid. The monomers were solids and soluble in water and ethanol. The structures of the monomers were determined by Fourier transform infrared (FTIR), ¹H, ¹³C, and ³¹P nuclear magnetic resonance (NMR) spectroscopy. The copolymerization behaviors of the synthesized monomers with glycerol dimethacrylate were first investigated in bulk using photodifferential scanning calorimetry at 40 °C with 2,2′‐dimethoxy‐2‐phenyl acetophenone as photoinitiator. Then, the solution copolymerization of the monomers with acrylamide in ethanol and water was studied, indicating that the synthesized monomers are incorporated into the copolymers. The acidic nature of the aqueous solutions of these monomers (pH values 1.72–1.87) is expected to give them etching properties important for dental applications. The interaction of the monomers with hydroxyapatite was investigated using ¹³C NMR and FTIR techniques. © 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 47: 1953–1965, 2009     

Synthesis and characterization of novel fluoride‐releasing monomers. II. Dimethacrylates containing bis(aminodiacetic acid) and their ternary zirconium fluoride complexes

Novel dimethacrylate monomers containing bis(aminodiacetic acid) chelating ligands with or without additional hydroxyl groups were synthesized, starting from 2,2‐bis(4‐hydroxy‐3‐methylphenyl)propane. The structures of the monomers were characterized by electrospray mass spectrometry (ESMS), ¹H NMR, and ¹³C NMR. The structures and relative stability of fluoride‐releasing monomers containing one or more ternary zirconium fluoride complex moieties were studied by ESMS. The most stable ternary zirconium fluoride complex was in the form of [LZrF]^?, where H₄L is the monomer containing bis(aminodiacetic acid) without additional hydroxyl groups. The synthesized monomer was photopolymerized with camphorquinone and 1‐phenyl‐1,2‐propane‐dione as initiators and N,N‐dimethylaminoethyl methacrylate as the accelerator. The fluoride release, fluoride recharge, compressive strength, and flexure strength were tested on the experimental dental composite containing 13.7 wt % synthesized monomer and three commercial flowable dental composites. The results showed that the experimental composite has significantly higher fluoride release and recharge capabilities than the commercial flowable composites. The compressive strength was comparable to that of the commercial materials. The water sorption and solubility met the requirement of the ISO Specification 4049. © 2005 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 43: 3153–3166, 2005     

Sulfobetaine‐containing diblock and triblock copolymers via reversible addition‐fragmentation chain transfer polymerization in aqueous media

A novel bifunctional acrylamido‐based reversible addition–fragmentation chain transfer (RAFT) chain‐transfer agent (CTA), N,N′‐ethylenebis[2‐(thiobenzoylthio)propionamide] (CTA2), has been synthesized and used for the controlled free‐radical polymerization of N,N‐dimethylacrylamide (DMA). A comparative study of CTA2 and the monofunctional CTA N,N‐dimethyl‐s‐thiobenzoylthiopropionamide (CTA1) has been conducted. Polymerizations mediated by CTA1 result in poly(N,N‐dimethylacrylamide) (PDMA) homopolymers with unimodal molecular weight distributions, whereas CTA2 yields unimodal, bimodal, and trimodal distributions according to the extent of conversion. The multimodal nature of the PDMAs has been attributed to termination events and/or chains initiated by primary radicals. The RAFT polymerization of DMA with CTA2 also results in a prolonged induction period that may be attributed to the higher local concentration of dithioester functionalities early in the polymerization. A series of ω‐ and α,ω‐dithioester‐capped PDMAs have been prepared in organic media and subsequently employed as macro‐CTAs for the synthesis of diblock and triblock copolymers in aqueous media with the zwitterionic monomer 3‐[2‐(N‐methylacrylamido)‐ethyldimethylammonio] propane sulfonate (MAEDAPS). Additionally, an ω‐dithioester‐capped MAEDAPS homopolymer has been used as a macro‐CTA for the block polymerization of DMA. To our knowledge, this is the first example of a near‐monodisperse, sulfobetaine‐containing block copolymer prepared entirely in aqueous media. The diblock and triblock copolymers form aggregates in pure water that can be dissociated by the addition of salt, as determined by ¹H NMR spectroscopy and dynamic light scattering. In pure water, highly uniform, micellelike aggregates with hydrodynamic diameters of 71–93 nm are formed. © 2003 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 41: 1262–1281, 2003     

Synthesis,characterization, and photocuring of siloxane‐oxirane monomers

The aim of this study was to synthesize, characterize, and evaluate alternative monomers for use in dentistry. Three siloxane‐oxirane low‐shrinkage monomers were synthesized, and the products’ conversion was followed by Fourier transform ‐ infrared spectroscopy. The products obtained were characterized by ¹H and ¹³C NMR and evaluated for viscosity and a refractive index. The polymerization was evaluated by formulating two experimental photoinitiation systems, which varied for the presence of 1,2 ethanediol. A ternary system with camphorquinone (CQ), ethyl 4‐dimethylaminobenzoate (EDAB), and diphenyliodonium hexafluorphosphate (DPI) was used as control. The degree of conversion was assessed by differential scanning calorimetry (DSC). The NMR confirmed the synthesis success with 75, 87, and 55% yields for the monomers synthesized. The viscosity and the refractive index of the monomers showed favorable rheological and physical behaviors for application in dentistry. Moreover, the presence of 1,2 ‐ ethanediol increased the degree of conversion of the siloxane‐oxirane monomers. This study showed a simple and effective way to synthesize siloxane‐oxirane monomers with a high potential for application in dental materials. © 2015 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2015 , 53, 1728–1733     

Effect of lithium perchlorate on the spontaneous copolymerization of 4‐vinylpyridine with various electron‐rich vinyl monomers

The spontaneous copolymerization of 4‐vinylpyridine (4‐VP) activated with lithium perchlorate (LiClO₄) with various electron rich monomers (p‐methoxystyrene, MeOSt; p‐methylstyrene, MeSt; styrene, St) was investigated in various solvent systems at 75°C. Increasing the LiClO₄ concentration and the nucleophilicity of the electron rich monomer increased the copolymer yields. Both ¹H‐NMR and elemental analysis confirmed the almost 1:1 copolymer structure for VP/MeOSt system which possessed high molecular weight and narrow polydispersity (PDI). Compared to 4‐VP activated with zinc chloride, LiClO₄ systems showed slightly lower yields and much narrower PDI. We also investigated the spontaneous copolymerization of 4‐VP activated with various protic acids in the reaction with various electron rich comonomers. However, generally protic salt forms showed less solubility in organic solvents and showed low molecular weight polymer products with low yields. The proposed initiation mechanism exhibits the formation of a σ‐bond between the β‐carbons of the two donor‐acceptor monomers, creating the 1,4‐tetramethylene biradical intermediate initiating the copolymerization. © 1999 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 37: 1709–1716, 1999     

Synthesis and characterization of alkylated N‐vinylformamide monomers and their polymers

N‐alkyl‐N‐vinylformamide monomers (alkyl: n‐butyl, hexyl, decyl, and dodecyl) are synthesized in two steps: first, preparation of N‐vinylformamide potassium salt by the reaction of N‐vinylformamide (NVF) with potassium t‐butoxide, then reaction with alkyl bromide. All four monomers are liquid and are characterized by IR, ¹H NMR, ¹³C NMR, and mass spectra. They exist as rotomers in solution and a 2D NOE experiment on the N‐hexyl containing polymer shows the E isomer to be favored. The polymerizability of the four monomers is from good to fair, depending upon the length of alkyl chain on the N‐atom‐‐the longer the chain length, the lower lower the polymerizability of monomer. The hydrolysis of poly(N‐hexyl‐N‐vinylformamide) and poly(N‐dodecyl‐N‐vinylformamide) under acidic and basic conditions was examined. Studies show that hydrolytic cleavage of formyl groups of poly (N‐alkylated‐N‐vinylformamide) depends on the hydrophobicity of the alkyl substituent on the N‐atom under acidic conditions; both polymers were hydrolyzed to only a minor extent under alkaline conditions. The N‐alkylated monomers can copolymerize with NVF and demonstrate amphiphilic properties. The copolymers demonstrate a critical aggregation concentration above which they can solubilize a water insoluble dye; the N‐hexyl containing copolymer stabilizes a castor oil‐in‐water emulsion. © 2004 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 42: 4994–5004, 2004     

Facile synthesis of hyperbranched polyimides from A2 + BB′2 monomers

Facile syntheses of hyperbranched polyimides were realized by the polymerization of A₂ + BB^′₂ monomers, 2,2‐bis(3,4‐dicarboxylphenyl) hexafluoropropane dianhydride (6FDA) + 2,4,6‐triaminopyrimidine (TAP), performed by mixing the monomers together in N‐methylpyrrolidone at 17% w/v concentrations with molar ratios of 6FDA:TAP ranging from 1:1 to 2:1. The lower reactivity of 2‐amino as compared with 4‐/6‐amino in TAP, demonstrated by ¹H NMR, was probably the main reason for no gelation formed during the polymerization although monomer conversions surpassed the theoretical gel points. Fourier transform infrared spectroscopy and NMR were used to verify the structures of the obtained polymers. ¹H NMR analysis indicated the degrees of branching (DB) of the polymers increased from 36 to 83% with the molar ratios of 6FDA:TAP increasing from 1:1 to 2:1. Molecular weights were determined by gel permeation chromatography, and inherent viscosities were measured. Glass‐transition temperature values, determined by differential scanning calorimetry, decreased when DB increased, and thermogravimetric analysis reflected the excellent thermal stability of the obtained hyperbranched polyimides. © 2002 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 40: 4563–4569, 2002     

Cationic copolymerization of indene with styrene derivatives: Synthesis of random copolymers of indene with high molecular weight

Random copolymers with high molecular weights of indene and p‐methylstyrene (pMeSt) were synthesized by cationic polymerization with trichloroacetic acid/tin tetrachloride in CH₂Cl₂ at low temperatures. When indene and pMeSt (1:1 v/v), for example, were polymerized at ?40 °C, both monomers were consumed at very similar rates to give a copolymer with high molecular weight [number‐average molecular weight (M_n): 8–9 × 10⁴]. This is indeed quite unexpected behavior for the combination of these two monomers because pMeSt polymerized over 1000 times faster than indene in the homopolymerization under the reaction conditions previously described. The product copolymer of indene and pMeSt had a random monomer sequence in it that was confirmed by NMR analyses and thermal‐property measurements. In sharp contrast with pMeSt, styrene and p‐chlorostyrene, which have no electron‐donating groups on the phenyl ring, led to low molecular weight polymers (M_n < 10,000) in the copolymerization with indene (1:1 v/v). © 2002 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 40: 2449–2457, 2002     

Controlled helical orientation of carbazole in amino acid derived poly(N‐propargylamide)s

Novel L ‐alanine and L ‐glutamic acid derivatized, carbazole‐containing N‐propargylamides [N‐(9‐carbazolyl)ethyloxycarbonyl‐L ‐alanine N′‐propargylamide and N‐(9‐carbazolyl)ethyloxycarbonyl‐L ‐glutamic acid‐γ‐benzyl ester N′‐propargylamide] were synthesized and polymerized with (nbd)Rh⁺[η⁶‐C₆H₅B^?(C₆H₅)₃] (nbd = norbornadiene) as a catalyst to obtain the corresponding polymers with moderate molecular weights in high yields. Polarimetry, circular dichroism, and ultraviolet–visible spectroscopy studies revealed that both poly[N‐(9‐carbazolyl)ethyloxycarbonyl‐L ‐alanine N′‐propargylamide] and poly[N‐(9‐carbazolyl)ethyloxycarbonyl‐L ‐glutamic acid‐γ‐benzyl ester N′‐propargylamide] took a helical structure with a predominantly one‐handed screw sense in tetrahydrofuran, CHCl₃, and CH₂Cl₂. The helix content of poly[N‐(9‐carbazolyl)ethyloxycarbonyl‐L ‐alanine N′‐propargylamide] could be tuned by heat or the addition of a protic solvent, and the helical sense of poly[N‐(9‐carbazolyl) ethyloxycarbonyl‐L ‐glutamic acid‐γ‐benzyl ester N′‐propargylamide] was inverted by heat in CHCl₃ or in mixtures of tetrahydrofuran and CH₂Cl₂. Poly[N‐(9‐carbazolyl) ethyloxycarbonyl‐L ‐alanine N′‐propargylamide] and poly[N‐(9‐carbazolyl)ethyloxycarbonyl‐L ‐glutamic acid‐γ‐benzyl ester N′‐propargylamide] also took a helical structure in film states. They showed small fluorescence in comparison with the monomers and redox activity based on carbazole. © 2006 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 45: 253–261, 2007     

Synthesis and cyclopolymerization of novel allyl‐acrylate quaternary ammonium salts

Novel allyl‐acrylate quaternary ammonium salts were synthesized using two different methods. In the first (method 1), N,N‐dimethyl‐N‐2‐(ethoxycarbonyl)allyl allylammonium bromide and N,N‐dimethyl‐N‐2‐(tert‐butoxycarbonyl)allyl allylammonium bromide were formed by reacting tertiary amines with allyl bromide. The second (method 2) involved reacting N,N‐dialkyl‐N‐allylamine with either ethyl α‐chloromethyl acrylate (ECMA) or tert‐butyl α‐bromomethyl acrylate (TBBMA). The monomers obtained with the method 2 were N,N‐diethyl‐N‐2‐(ethoxycarbonyl)allyl allylammonium chloride, N,N‐diethyl‐N‐2‐(tert‐butoxycarbonyl)allyl allylammonium bromide, and N,N‐piperidyl‐N‐2‐(ethoxycarbonyl)allyl allylammonium chloride. Higher purity monomers were obtained with the method 2. Solution polymerizations with 2,2′‐azobis(2‐amidinopropane) dihydrochloride (V‐50) in water at 60–70°C gave soluble cyclopolymers which showed polyelectrolyte behavior in pure water. Intrinsic viscosities measured in 0.09M NaCl ranged from 0.45 to 2.45 dL/g. ¹H‐ and ¹³C‐NMR spectra indicated high cyclization efficiencies. The ester groups of the tert‐butyl polymer were hydrolyzed completely in acid to give a polymer with zwitterionic character. © 1999 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 37: 901–907, 1999     

Synthesis and polymerization of new styryl and methacryloyl monomers containing acidic saccharide moieties

New styryl‐type water‐insoluble and methacryloyl‐type water‐soluble monomers, N‐(p‐vinylbenzyl)‐1,2‐O‐isopropylidene‐6‐D ‐glucofuranuronamide and N‐(2‐methacryloylamino)ethyl‐1,2‐O‐isopropylidene‐6‐D ‐glucofuranuronamide, were synthesized from the most common acidic saccharide, D ‐glucuronic acid. Their radical homopolymerizations and copolymerizations with styrene and acrylamide were tried under various conditions. The isopropylidene groups in the resulting polymers were removed in a mixture of trifluoroacetic acid and water (2/1 v/v) to give the corresponding polymers with many pendant D ‐glucopyranuronyl groups with reactive reducing groups. The pendant reducing ends may be useful as potential binding sites under a hydrophilic atmosphere. © 2001 John Wiley & Sons, Inc. J Polym Sci Part A: Polym Chem 39: 3893–3901, 2001     

Microwave‐assisted synthesis and characterization of heterocyclic,and optically active poly(amide‐imide)s incorporating L‐amino acids

N,N′‐Pyromelliticdiimido‐di‐L ‐alanine ( 1 ), N,N′‐pyromelliticdiimido‐di‐L ‐phenylalanine ( 2 ), and N,N′‐pyromelliticdiimido‐di‐L ‐leucine ( 3 ) were prepared from the reaction of pyromellitic dianhydride with corresponding L ‐amino acids in a mixture of glacial acetic acid and pyridine solution (3/2 ratio) under refluxing conditions. The microwave‐assisted polycondensation of the corresponding diimide‐diacyl chloride monomers ( 5–7 ) with 4‐phenyl‐2,6‐bis(4‐aminophenyl) pyridine ( 10 ) or 4‐(p‐methylthiophenyl)‐2,6‐bis(4‐aminophenyl) pyridine ( 12 ) were carried out in a laboratory microwave oven. The resulting poly(amide‐imide)s were obtained in quantitative yields, and they showed admirable inherent viscosities (0.12–0.55 dlg^?1), were soluble in polar aprotic solvents, showed good thermal stability and high optical purity. The synthetic compounds were characterized by IR, MS, ¹H NMR, and ¹³C NMR spectroscopy, elemental analysis, and specific rotation. Copyright © 2008 John Wiley & Sons, Ltd.     

Oxidation of cellulose fibers mediated by nonpersistent nitroxyl radicals

Three different nonpersistent radicals bearing >NO^? moiety have been used to oxidize the viscose fibers at room temperature and alkaline pH. The generation of the free radical species was achieved in situ, from their corresponding ? OH precursors: 1‐hydroxybenzotriazole, violuric acid, and N‐hydroxy‐3,4,5,6‐tetraphenylphthalimide. Three different routes were used: (i) in the presence of metallic cocatalyst (lead tetraacetate), (ii) under metal‐free conditions (anthraquinone as organic cocatalyst), and (iii) a homolytically scission of ? OH bond through a 365‐nm UV irradiation. The oxidized fibers were subjected to attenuated total reflection FTIR characterization, potentiometric titration, wide angle X‐ray, energy dispersive X‐ray analyses, microscopic investigations, and solid‐state ¹³C‐NMR. The patterns of CP/MAS ¹³C‐NMR spectra revealed that the oxidation occurred at the C6 primary hydroxyl groups of cellulose. Notably, as a result of the introduction of hydrophilic carboxylate groups, the water retention values of the oxidized fibers increased by 35% as compared to the original nonoxidized sample. © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2010     

Synthesis and characterization of blue‐light emissive carbazole containing perfluorocyclobutyl arylene ether polymers

A series of N‐alkyl/aryl carbazole 3,6‐substituted arylene trifluorovinyl ether (TFVE) monomers were synthesized in high purity and yield from a concise four‐step synthesis using carbazole as a starting material. Condensate‐free, step‐growth chain extension of the monomers afforded perfluorocyclobutyl (PFCB) arylene ether homo‐ and copolymers as solution processable, optically transparent blue‐light emissive materials. Arylene TFVE monomers and conversion to PFCB arylene ether polymers were structurally elucidated and purity confirmed by high resolution mass spectroscopy, NMR (¹H, ¹³C, and ¹⁹F) spectroscopy, gel permeation chromatography, and attenuated total reflectance Fourier transform infrared analysis. Thermal analysis by differential scanning calorimetry and thermogravimetric analysis revealed glass transition temperatures >150 °C and onset of decomposition in nitrogen >410 °C with 40 wt % char yield up to 900 °C. Optical and electrochemical studies included solution (tetrahydrofuran) and solid state (spin cast thin film) UV–vis/fluorescence spectroscopy and cyclic voltammetry which showed structure dependence of these blue emissive systems on the nature of the N‐alkyl/aryl carbazole substitution in either homo‐ or copolymer configurations. © 2013 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2014 , 52, 552–560     

Synthesis and helical conformation of poly(N‐propargylamides) carrying L‐aspartic acid in the side chain

Aspartic acid‐based novel poly(N‐propargylamides), i.e., poly[N‐(α‐tert‐butoxycarbonyl)‐L ‐aspartic acid β‐benzyl ester N′‐propargylamide] [poly( 1 )] and poly[N‐(α‐tert‐butoxycarbonyl)‐L ‐aspartic acid α‐benzyl ester N′‐propargylamide] [poly( 2 )] with moderate molecular weights were synthesized by the polymerization of the corresponding monomers 1 and 2 catalyzed with (nbd)Rh⁺[η⁶‐C₆H₅B^?(C₆H₅)₃] in CHCl₃ at 30 °C for 2 h in high yields. The chiroptical studies revealed that poly( 1 ) took a helical structure in DMF, while poly( 2 ) did not in DMF but did in CH₂Cl₂, CHCl₃, and toluene. The helicity of poly( 1 ) and poly( 2 ) could be tuned by temperature and solvents. Poly( 2 ) underwent solvent‐driven switch of helical sense, accompanying the change of the tightness. © 2005 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 43: 5168–5176, 2005     

Urea dimethacrylates functionalized with bisphosphonate/bisphosphonic acid for improved dental materials

Incorporation of bisphosphonate/bisphosphonic acid groups in dental monomer structures should increase interaction of these monomers with dental tissue as these groups have strong affinity for hydroxyapatite. Therefore, new urea dimethacrylates functionalized with bisphosphonate (1a, 1b) and bisphosphonic acid (2a, 2b) groups are synthesized and evaluated for dental applications. Monomers 1a and 1b are synthesized from 2‐isocyanatoethyl methacrylate (IEM) and two bisphosphonated amines (BPA1 and BPA2), prepared as reported elsewhere. Selective dealkylation of the bisphosphonate ester groups of 1a and 1b using trimethylsilyl bromide (TMSBr) gives monomers (2a and 2b) with bisphosphonic acid functionality. X‐ray diffractometer (XRD), Raman spectroscopy, and X‐ray photoelectron spectroscopy (XPS) analyses of monomer‐treated HAP particles show that 2a induces formation of stable monomer‐calcium salts, similar to 10‐methacryloyloxydecyl dihydrogen phosphate (MDP), with higher chemical interaction than 2b. The photopolymerization studies indicate good copolymerizability with commercial dental monomers. In vitro studies on NIH 3T3 mouse embryonic fibroblast cells have clearly shown that the tested monomers (1b and 2b) are not toxic according to the MTT standards. All these properties make these monomers suitable as biocompatible cross‐linkers/adhesives for dental applications. © 2017 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2017 , 55, 3195–3204