Preparation and characterization of porous polymeric microspheres obtained from multifunctional methacrylate monomers

Synthesis and properties of the new difunctional methacrylate monomer 2‐hydroxy‐3‐methacryloyloxypropoxybenzene are presented. This monomer was applied for the synthesis of porous microspheres. It was copolymerized with trimethylolpropane trimethacrylate in the presence of two pairs of pore‐forming diluents dodecane and toluene, and n‐decanol and toluene. Influence of diluents composition on their porous structures was studied. Thermal resistance and tendency to swell in different organic diluents for a chosen sample were also determined. © 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 6165–6174, 2008     

Synthesis and characterization of new quinoline monomers

New quinoline-2,6-dicarboxylic acid and 6-aminoquinoline-2-carboxylic acid which are potential monomers for the introduction of quinoline units in commercial polymers such as polyamides, polyesters, etc. have been synthesized.     

Synthesis and characterization of polymerizable bisphthalonitrile monomers

The reactions of 4-aminophthalonitrile (APN) with 3,3′,4,4′-benzophenone tetracarboxylic dianhydride (BPTDA), and with 1,2,3,4-benzenetetracarboxylic dianhydride (PMDA) have been studied to optimize the conditions for the synthesis of monomeric thermosetting bisphthalonitrile compound. Suitable procedures for the synthesis of the two monomers are presented. Elemental analyses, IR spectra, dynamic thermogravimetric analyses, differential scanning calorimetry, ¹H-NMR, and mass spectral studies have been used to characterize these compounds. Preliminary observations show that these materials can be polymerized to give high-temperature-resistant materials.     

Ketene acetal monomers: Synthesis and characterization

A new, facile, and high-yield synthesis of ketene acetals derived from readily available and inexpensive starting materials has been developed. For example, an α,β-unsaturated aldehyde can be condensed with an alkane diol to afford a 2-vinyl substituted cyclic acetal. This latter compound can be converted to the desired cyclic ketene acetal by isomerization of the double bond in the presence of tris(triphenylphosphine)ruthenium(II) dichloride. Good to excellent yields of cyclic ketene acetals were obtained employing this method. The novel monomers were fully characterized by IR, NMR, and by elemental analysis. © 1996 John Wiley & Sons, Inc.     

Synthesis and characterization of new chiral mesogenic monomers

New mesogenic monomers carrying substituted biphenylyl rings linked to acryloyl or methacryloyl moieties through straight or chiral flexible spacers have been synthesized. All the investigated monomers, independent of the side group chirality, have been found to form ordered smectic phases, most probably of the S₁ type. The asymmetric methyl substitution on the flexible spacer leads to an expansion of the temperature range of mesophase stability. The chiral monomers induce a helical structure when mixed with appropriate nematogens. The fingerprint texture of a contact mixture of the chiral methacrylate prepared in this work, with a nematic methacrylate synthesized previously, has been found not to change after UV-initiated polymerization.     

Synthesis and characterization of multifunctional propenyl‐endcapped aromatic co‐monomers and their use as bismaleimide modifiers

A series of novel modifiers for bismaleimide, bearing propenyl and phenoxy functional groups has been synthesized. Structural information of the monomers was obtained through Fourier transform infrared spectroscopy (FT‐IR), nuclear magnetic resonance (NMR) spectroscopy and elemental analysis. Polymerization characteristics demonstrate that all four systems prepared have a cure temperature below 210°C. This remarkably lower cure temperature compared to that of other polymerization reactions involving diallyl bisphenol A and bismaleimide (DBMI) originates from propenyl groups being present in the structures as well as their larger free volume. The rheological behaviors leading to low melt viscosities and the wide process window of the prepolymer are particularly suitable characteristics for the production of performance resin‐based composite materials via resin transfer molding processes. The dynamic mechanical analysis of the materials reveals glass transition temperatures in a range between 260°C and 293°C. Thermal stabilities show a 5% weight loss at temperatures ranging from 363°C to 428°C with the production of char ranging from 38.5% to 57.6% at 800°C under nitrogen. The latter is a clear indication for the excellent thermal stabilities featured by the cured resins. Furthermore, the dielectric properties exhibit a significantly lower dielectric constant and dissipation factors of the propenyl‐modified cured systems compared to those of DBMI resins at 10 GHz. Copyright © 2015 John Wiley & Sons, Ltd.     

Synthesis and characterization of novel multifunctional epoxy resin

A novel multifunctional epoxy resin was synthesized by polyphenol and epichlorohydrin.The structure and molecular weight ofthe multifunctional epoxy were characterized by FTIR and ESI-MS.DSC and DMTA were used to investigate the thermal propertyof multifunctional epoxy cured by DDS.The thermal resistance of the synthesized multifunctional epoxy was much better than astandard diglycidyl ether of bisphenol-A epoxy.     

Synthesis and photopolymerizations of new phosphonated monomers for dental applications

Three novel phosphonated methacrylate monomers have been synthesized and studied for use in dental applications. Two of the monomers were synthesized from the reactions of glycidyl methacrylate (GMA) with (diethoxy‐phosphoryl)‐acetic acid (monomer 1 ) and (2‐hydroxy‐ethyl)‐phosphonic acid dimethyl ester (monomer 2 ). These monomers showed high crosslinking tendencies during thermal bulk and solution polymerizations. The third monomer (monomer 3 ) was prepared by the reaction of bisphenol A diglycidylether (DER) with (diethoxy‐phosphoryl)‐acetic acid and subsequent conversion of the resulting diol to the methacrylate with methacryloyl chloride. The homopolymerization and copolymerization behaviors of the synthesized monomers were also investigated with glycerol dimethacrylate (GDMA), triethylene glycol dimethacrylate (TEGDMA), and 2,2‐bis[4‐(2‐hydroxy‐3‐methacryloyloxy propyloxy) phenyl] propane (bis‐GMA) using photodifferential scanning calorimetry at 40 °C using 2,2′‐dimethoxy‐2‐phenyl acetophenone (DMPA) as photoinitiator. Monomer 1 showed polymerization rate similar or greater than dimethacrylates studied here but with higher conversion. The maximum rate of polymerizations decreased in the following order: 1 ～TEGDMA>GDMA～bis‐GMA～ 3 > 2 . A synergistic effect in the rate of polymerization was observed during copolymerizations. © 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 2290–2299, 2008     

Polymerization of photocurable commercial dental methacrylate-based composites

Due to their excellent aesthetics, photopolymers have been extensively used in several dentistry applications. However, several problems are reported, e.g. low mechanical and abrasion resistance, shrinkage during polymerization, etc. Properties of the final restorations are intrinsically related to the polymerization stage, which can be conveniently studied by photocalorimetry. In the present work the polymerization reaction and the filler content of different photocurable commercial dental methacrylate-based composites were studied by means of photocalorimetry and thermogravimetry, respectively. The results show that the values of curing rate, the heat of polymerization and the filler content vary significantly from one composite to another.     

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     

Synthesis and photopolymerizations of first monomers with phosphonate and bisphosphonate or phosphonic and bisphosphonic acid functionalities for potential dental applications

The first monomers containing both phosphonate and bisphosphonate (M1) or phosphonic and bisphosphonic acid (M2) functionalities are synthesized, aiming to improve binding abilities of self-etching adhesive systems and composites: An amine having both phosphonate and bisphosphonate functionalities is prepared via Michael addition reaction between diethyl (6-aminohexyl)phosphonate and tetraethyl vinylidene bisphosphonate, its reaction with 2-isocyanatoethyl methacrylate gives M1 which is converted to M2 by selective dealkylation of the phosphonate/bisphosphonate ester groups. Their copolymerization with commercial dental monomers (bisphenol A glycidyl methacrylate, triethylene glycol dimethacrylate, and 2-hydroxyethyl methacrylate) investigated by photo-differential scanning calorimetry shows adequate photopolymerization rate and conversion. X-ray diffraction, Fourier transform infrared, and X-ray photoelectron spectroscopy analyses of M2-treated hydroxyapatite particles show formation of stable M2-calcium salts. These monomers are assessed to be not toxic according to MTT standards by in vitro cytotoxicity studies with NIH 3T3, U2OS, and Saos-2 cells. All these properties make these monomers potential candidates as biocompatible components for dental adhesives and composites. © 2018 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2018 , 56, 2739–2751     

Synthesis, spectroscopic characterization and alignment of novel azobenzene-containing monomers

A series of novel bifunctionalized photochromic monomers were synthesized, focusing on those with polymerizable acrylic/methacrylic groups attached to both ends of an azobenzene core via flexible spacers. The phase behaviour of the monomers was investigated using DSC, polarizing optical microscopy and X-ray diffraction. The change in UV-vis absorbance of the monomers under illumination with non-polarized/polarized UV light was studied for both solutions and thin films; also studied was its relaxation in the dark. On illumination with LPUV light, in-plane reorientation of the molecules normal to the polarization of the exciting UV light, and aggregation of the molecules in the films, were found.     

Synthesis and evaluations of bisphosphonate‐containing monomers for dental materials

Two new bismethacrylamide ( 1 , 2 ) and two new methacrylamide ( 3 , 4 ) dental monomers were synthesized. In each group, one monomer contains a bisphosphonate group, the other a bisphosphonic acid group. Monomer 1 and 3 were synthesized by amidation of 2‐(2‐chlorocarbonyl‐allyloxymethyl)‐acryloylchloride and methacryloyl chloride with tetraethyl aminomethyl‐bis(phosphonate) and converted to the bisphosphonic acid monomers 2 and 4 by hydrolysis with trimethylsilyl bromide. Monomer 1 (m.p.: 71–72 °C), monomer 3 ( 33–34 °C), and monomer 4 (no m.p.) were obtained as white solids and monomer 2 a viscous liquid, soluble in water. Homopolymerization of 1 gave crosslinked polymers, indicating its low cyclization tendency. The photopolymerization studies indicated that its copolymerizability with 2,2‐bis[4‐(2‐hydroxy‐3‐methacryloyloxy propyloxy) phenyl] propane and 2‐hydroxyethyl methacrylate (HEMA) without changing their rates and conversions significantly means that it could be used as a biocompatible crosslinker. Although monomer 2 showed low polymerizability, because of its good performance in terms of solubility, hydrolytic stability, hydroxyapatite interaction, acidity, and copolymerizability with HEMA, it shows potential to be used in self‐etching dental adhesives. The thermal polymerization of 3 resulted in soluble polymers and evaluation of monomer 4 in terms of solubility, acidity, and copolymerizability with HEMA indicated its potential as an adhesive monomer. © 2012 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2012     

Synthesis and characterization of novel epoxy monomers and liquid crystal thermosets

Four new epoxy monomers have been synthesized and characterized as part of a program to prepare novel liquid crystal thermoset (LCT) materials. Three of the new epoxy monomers contained a biphenyl mesogen and were not liquid crystalline (LC). The remaining epoxy monomer, which contained a 1,4-dibenzoyloxybenzene mesogen, was synthesized in an overall yield of 30% and displayed a broad (83°C) nematic liquid crystalline phase. The new liquid crystalline epoxy monomer was cured at 120°C and postcured at 175°C with a stoichiometric amount of 1,4-phenylenediamine. The thermal transitions of the resulting LCT were studied by differential scanning calorimetry (DSC), polarized light optical microscopy (POM), thermomechanical analysis (TMA), and wide angle x-ray diffraction (WAXD) as a function of cure time and temperature. A process characterization diagram was constructed which shows that LCTs based on this new LC monomer can be processed in the liquid crystalline phase over a broad range of times and temperatures. Qualitative agreement with previous epoxy LCT results was found, as LCT's with smectic phases and without clearing temperatures were observed at long cure times (high crosslink densities), whereas nematic phases with clearing temperatures predominated in networks at short cure times (low crosslink densities). © 1993 John Wiley & Sons, Inc.     

Synthesis and characterization of the novel type of polymerizable bisphthalonitrile monomers

Three new bisphthalonitrile derivatives are prepared by the nucleophilic displacement of the nitrosubstituent from 4-nitrophthalonitrile with 9,9-bis(4-hydroxyphenyl)fluorene; 9,9-bis(3,5-dimethyl-4-hydroxyphenyl)fluorene, and phenolphthalein in the presence of potassium carbonate. The reaction has been carried out in dimethylsulfoxide solvent. These monomers are characterized by elemental analysis, FT-IR, ¹H NMR, TGA, DSC, and mass spectral studies. A tentative mechanism for the fragmentation of the compounds is given to explain the mass spectral data. The compounds are expected to be useful to prepare thermally stable thermosetting phthalocyanine polymers.     

Carbazole main-chain polymers for multifunctional materials: Synthesis and characterization

A series of α,ω-bis(3-formylcarbazolyl)alkane monomers have been prepared starting from carbazole and α,ω-dibromoalkane in two steps. Main-chain polymers with carbazole substituted with one acceptor group as the nonlinear optical (NLO) chromophores and photoconductive moieties were synthesized by the Knoevenagel polycondensation of α,ω-bis(3-formylcarbazolyl)alkane and 1,6-bis(cyanoacetoxy)hexane using 4-(N,N-dimethyl)pyridine (DMAP) as a base. This Knoevenagel polycondensation involved two stages: polycondensation was first carried out in tetrahydrofuran solution, and then polycondensation was allowed to continue in the solid-state after removal of solvent. All of these main-chain polymers characterized by spectroscopic methods and elemental analyses are soluble in common low boiling organic solvents, such as chloroform. These polymers were found to be amorphous with glass transition temperatures in the range of 94–117°C by differential scanning calorimetry. This two-stage polycondensation gave polymers with weight-average molecular weight in the range of 25,000–72,000 g/mol by gel permeation chromatography. The study of the nonlinear optical and photorefractive properties of these polymers is in progress. © 1996 John Wiley & Sons, Inc.     

Synthesis and characterization of optically active polyamides derived from carbohydrate-based monomers

The synthesis of three new stereoregular AB-type polyamides based on D -ribono-1,4-lactone, L -arabinose, and D -xylose has been carried out by the active ester polycondensation method. These polyamides were characterized by elemental analysis, IR and NMR spectroscopies, and powder X-ray diffraction. They displayed optical activity and had a pronounced affinity to water, although they were not soluble in this solvent. The polyamide obtained from D -ribono-1,4-lactone was highly crystalline and yielded films with spherulitic texture. © 1997 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 35: 3645–3653, 1997     

Synthesis and characterization of novel photopolymerizable multifunctional 2-propenyl ether analogues

Monomers bearing two, three, four, and six cationically polymerizable aryl 2-propenyl groups were synthesized and characterized. These compounds can be readily prepared by the catalytic isomerization of the corresponding allyl compounds. Strong bases and tris(triphenylphosphine)ruthenium(II) dichloride were used as the catalysts for these isomerizations. A study of the cationic photopolymerizations of these novel monomers was carried out using a diaryliodonium salt photoinitiator. The polymerization involves a stepwise condensation of the monomers followed by an intramolecular ring closure to form polyindanes. The resulting photopolymerized polymers underwent thermal oxidative decomposition at temperatures over 430°C. © 1993 John Wiley & Sons, Inc.