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Transparent, film-forming fluorinated arylene vinylene ether (FAVE) polymers with enchained triarylamine (TAA) moieties were prepared and characterized. Control over fluoro-olefin content within the backbone, as a function of base, was confirmed and postpolymerization dehydrofluorination was shown to increase fluoroolefin content from 5 to 31 mol %. Thermal cross-linking was found to occur approximately 100 °C lower than in traditional FAVE polymers (ca. 160 °C). Electrochemical analysis demonstrated the enchained TAA retained its established electrochemical character. The latent reactivity of the TAA was explored via electrophilic aromatic substitution and formylation reactions toward precise functionalization for specific electro-optic applications and others.

Perfluorocycohexenyl (PFCH) aromatic ether polymers were synthesized by step-growth polycondensation of polycyclic aromatic hydrocarbon (PAH) bisphenols and decafluorocyclohexene (DFCH) affording a new class of unsaturated semi-fluoropolymers containing the rigid PAH linkage. Two acenaphthenequinone and two phenanthrenedione derived PAH bisphenols underwent base-mediated step-growth vinyl addition/elimination polymerization with DFCH to give polymers with well-defined unsaturation, moderate molecular weights, and variable glass transition (Tg) and thermal decomposition (Td) temperatures based on the starting PAH bisphenol monomer. With one exception exhibiting a low degree of crystallinity, PFCH polymers with PAH bisphenols were amorphous with Tg ranging from 184 to 240 °C. The new polymers contain intact unsaturation and reactive PAH moieties amenable for selective post-polymerization functionalization and crosslinking.

This study examines perfluorocyclobutyl (PFCB) aromatic ether polymers and demonstrates, for the first time, their potential as corrosion-resistant coatings. PFCB polymers are a distinct class of semi-fluorinated polymers that are based on thermal cyclopolymerization of aromatic trifluorovinyl ethers. They combine the flexibility and thermal stability of aromatic ethers with strong fluorocarbon linkages. Electrochemical impedance spectroscopy and potentiodynamic scans reveal that PFCB coatings display protective barrier properties against corrosion attack nearly equal to that of polyvinylidene fluoride (PVDF) coatings. The PFCBs also show excellent adhesion to metal surfaces and nonstick properties comparable to that of PVDF. Combined with their high thermal resistance, PFCBs may lead to new corrosion-resistant coatings in marine, oil and gas, and other applications.

Three classes of semi-fluorinated aromatic ether polymers, namely: perfluorocyclobutyl (PFCB), perfluorocycloalkenes (PFCA), and fluorinated arylene vinylene ether (FAVE), which are mostly amorphous have been reported via step-growth polymerization of fluoroalkenes. Unlike traditional fluoropolymers which have higher degree of crystallinity and are plagued by lack of solubility in common organic solvents, these uncured semi-fluorinated polymers are readily soluble in most organic solvents resulting in improved processability. In addition, all three semi-fluorinated polymers are versatile and can be custom-designed and fabricated into linear, telechelic, alternating and segmented-block, and network polymers, facilitating applications in optics, optoelectronic, photonics, proton exchange membranes, sensors, and fuel cells. Major aim of this timely review is to provide account of synthetic opportunities these semi-fluorinated offer in various applications.

Many desirable characteristics of polymers arise from the method of polymerization and structural features of their repeat units, which typically are responsible for the polymer’s performance at the cost of processability. While linear alternatives are popular, polymers composed of cyclic repeat units across their backbones have generally been shown to exhibit higher optical transparency, lower water absorption, and higher glass transition temperatures. These specifically include polymers built with either substituted alicyclic structures or aromatic rings, or both. In this review article, we highlight two useful ring-forming polymer groups, perfluorocyclobutyl (PFCB) aryl ether polymers and ortho-diynylarene- (ODA) based thermosets, both demonstrating outstanding thermal stability, chemical resistance, mechanical integrity, and improved processability. Different synthetic routes (with emphasis on ring-forming polymerization) and properties for these polymers are discussed, followed by their relevant applications in a wide range of aspects.

Semi-fluorinated arylene vinylene ether (FAVE) telechelomers and their chain extended PFCB polymers were synthesized via base catalyzed step-growth polymerization of polycyclic aromatic hydrocarbon (PAH) bisphenols and commercially available 4,4ꞌ-bis(4-trifluorovinyloxy)biphenyl (TFVE-BP) monomer. Soluble polymers were obtained in good yield, gave transparent free-standing films, and were characterized by 19F NMR, TGA, DSC, GPC, water contact angle and AFM. Thermal analysis by differential scanning calorimetry (DSC) revealed Tg values ranging from 150 to 168 °C. The new polycyclic aromatic FAVE polymers possess intact trifluorovinyl ether (TFVE) end groups susceptible to thermal chain extension leading to perfluorocyclobutyl (PFCB) aryl ether polymers with Tg ranging from 149 to 174 °C. Semi-fluorinated telechelic polymers with controlled terminal and enchained unsaturation with latent crosslinking ability may find use in specialty applications such as photonics or gas separation technologies.

The effects of compounded hydrogenated–fluorinated surfaces formed by perfluorocyclobutane (PFCB)-containing polymers on the alignment of 4,4′-octylcycanobiphenyl (8CB), a liquid crystal that exhibits both nematic and smectic phases, were investigated. The inherent segregation between fluorine- and hydrogen-rich segments produced structured interfaces with fluorinated and protonated nano domains. The morphologies of the interfaces and their corresponding surface energies were probed by AFM and the alignment of 8CB was investigated by polarized optical microscopy. We found that varying the fluorine content controlled both the structure and the interfacial morphology. The 8CB layer orientation was strongly affected by the interracial energies. With increasing fluorine content the homeotropic alignment temperature range of 8CB in the nematic phase was increased and that of the smectic phase was hardly affected. The impact observed was attributed to competition between anchoring effects and elasticity of the LC layers.

Suzuki polycondensation (SPC) as an alternative strategy has been utilized for the first time to readily yield functional perfluorocyclobutyl (PFCB) aryl ether polymers, which are difficult to obtain via the traditional [2+2] thermal cyclopolymerization strategy. Using two reactive PFCB aryl ether molecules as monomers, the biphenyl PFCB aryl ether polymer without any functionality was first prepared and exhibited good thermal stability, up to 450 °C at 8% weight loss (N2). By choosing appropriate functional monomers, aldehyde-functionalized PFCB aryl ether polymer precursor was also successfully prepared. Post-polymerization modification of this polymer precursor via Knoevenagel condensation yielded three distinct PFCB aryl ether polymers containing thermally stable triarylamine-based electro-optic chromophores.

A method for the preparation of AB-type monomers with complimentary fluoro-olefin and phenol functionalities is described. The three-step process is amenable to commercial scale up and uses widely-available, commercial reagents including bisphenols and perfluorocycloalkene (PFCA) compounds. Title compounds and intermediates were characterized via multi-nuclear NMR and FT-IR spectroscopy providing structural and mechanistic elucidation of PFCA step-growth polymerizations. The formation of vinyl and allyl substituted products were quantified and shown to be dependent on PFCA ring size and reaction medium. Nearly equal amounts of vinyl- and allyl-substituted products were observed with perfluorocyclohexene (PFCH) while 2–11% allyl-substitution was observed with perfluorocyclopentene (PFCP), depending on reaction medium polarity. Previous PFCA research and characterization of title compounds suggests that fluoride-catalyzed rearrangement is primarily responsible the formation of two substitution products. Polymerization of an AB-type monomer derived from bisphenol A is demonstrated and was shown to reproducibly result in film-forming polymers with higher molecular weights than previously described methods.

A variety of perfluorocycloalkenyl (PFCA) aryl ether monomers and polymers with enchained triarylamine units were successfully synthesized, characterized and reported here. These polymers are highly thermally stable and show variable thermal properties. Successful conversion of the newly synthesized TAA enchained perfluorocyclopentenyl (PFCP) aryl ether polymers via formylation and EAS demonstrates the synthetic versatility of TAA moiety and provides an excellent option for application specific post polymerization reactions. The cross-linking behavior of PFCP aryl ether polymers was studied under different reaction conditions. The combination of processability, thermal stabilities, and tailorability makes these polymers suitable for a wide variety of applications including electro-optics, proton exchange membranes and super-hydrophobic applications.

A novel class of semifluorinated perfluorocyclohexenyl (PFCH) aryl ether homo/copolymers was successfully synthesized with high yield through the step-growth polymerization of commercially available bisphenols and decafluorocyclohexene in the presence of a triethylamine base. The synthesized polymers exhibit variable thermal properties depending on the functional spacer group (R). PFCH aryl ether copolymers with random and alternating architectures were also prepared from versatile bis-perfluorocyclohexenyl aryl ether monomers. The PFCH polymers show high thermal stabilities with a 5% decomposition temperature ranging from 359 to 444 °C in air and nitrogen atmosphere. These semifluorinated PFCH aromatic ether polymers contain intact enchained PFCH olefin moieties, making further reactions such as crosslinking and application specific functionalization possible. © 2013 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2014, 52, 232–238

A unique class of perfluorocycloalkenyl (PFCA) aryl ether monomers was synthesized from commercially available perfluorocycloalkenes (PFCAs) and bisphenols in good yields. This facile one pot reaction of perfluorocycloalkenes, namely, octafluorocyclopentene (OFCP), and decafluorocyclohexene (DFCH), with bisphenols occurs at room temperature via an addition–elimination reaction in the presence of a base. The synthesis of PFCA monomers and their condensation with bisphenols lead to perfluorocycloalkenyl (PFCA) aryl ether homopolymers and copolymers with random and/or alternating polymer architectures.

A new class of partially fluorinated alternating aryl/alkyl vinylene ether (FAVE) polymers were prepared from addition polymerization of aryl trifluorovinyl ethers (TFVEs) with 1,4-butanediol or 4-hydroxybenzyl alcohol. Monodisperse FAVE telechelic polymers were also prepared possessing latent thermal reactivity which afforded chain-extended perfluorocyclobutyl (PFCB) aryl ethers via step-growth [2 + 2] cyclodimerization of the aryl TFVEs. Both linear and PFCB chain-extended FAVE polymers produced thermally robust, optically transparent, flexible spin-cast films. The FAVE polymers and their telechelic polymers were characterized using 19F NMR and 1H NMR complemented with molecular weight analysis using gel permeation chromatography and thermal analysis employing differential scanning calorimetry and thermogravimetry. © 2013 Society of Chemical Industry

Surface modification of ground rubber tire (GRT) was performed by bulk polymerization of acrylic acid (AA) without using any initiator. Two different sizes of GRT were used for this project: 40 mesh (often used in Asphalt Industry), and 300 mesh which is used in other industries. The concentration of the monomer (acrylic acid), reaction temperature and the reaction time (1 and 3 h) are important factors on the grafting degree – especially because our goal was not to use any initiator during the reaction (there are well known procedures for grafting of polymers by using different type of initiators). Our effort was towards simplifying the grafting process and to make it much faster and less expensive (more acceptable by the industry). The microstructural and morphological changes of the GRT particles were characterized by Attenuated Total Reflectance Fourier transform infrared spectroscopy (ATR-FTIR), scanning electron microscopy (SEM), viscosity test of the modified asphalt binder [PG 64-22 asphalt binder with virgin GRT particles (40 and 300 mesh), and PG 64-asphalt binder with AA treated GRT particles of the same size]. Dynamic shear rheometer (DSR) test of the modified asphalt binder was also performed. Thermal gravimetric analysis (TGA) was investigated on untreated and AA treated 300 mesh GRT particles. Results showed that with the addition of surface modified GRT particles increased the viscosity and failure temperature values of asphalt binder regardless of binder source and grade.

A unique class of aromatic ether polymers containing perfluorocyclopentenyl (PFCP) enchainment was prepared from the simple step growth polycondensation of commercial bisphenols and octafluorocyclopentene (OFCP) in the presence of triethylamine. Model studies indicate that the second addition/elimination on OFCP is fast and polycondensation results in linear homopolymers and copolymers without side products. The synthesis of bis(heptafluorocyclopentenyl) aryl ether monomers and their condensation with bisphenols further led to PFCP copolymers with alternating structures. This new class of semifluorinated polymers exhibit surprisingly high crystallinity in some cases and excellent thermal stability.

Fluorinated arylene vinylene ether (FAVE) polymers were prepared from the base-promoted addition of commercial 2,2-bis(4-hydroxyphenyl)hexafluoropropane (6F bisphenol A) to aryl trifluorovinyl ether (TFVE), 2,2′-bis(4-trifluorovinyloxybiphenyl)-1,1,1,3,3,3-hexafluoropropane. The step-growth polymerization kinetics by using stoichiometric NaH and catalytic Cs2CO3 were investigated by monitoring the 19F NMR signals of the aryl TFVEs. The nth order kinetic model was used to determine rate constants over a series of programmed temperatures. Polymerization using stoichiometric NaH resulted in second-order kinetics with an activation energy of 59 kJ/mol. This model kinetic study provided insight into the mechanistic pathways of the FAVE polymer system that has recently shown a lot of interest in many areas of materials science. © 2011 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2011

Nitric oxide (NO) plays an important role in physiological functions in the body, naturally synthesized by nitric oxide synthase. NO has been shown to enhance wound healing, generating research interest in the incorporation of NO into thromboresistant polymers for medical devices. Such polymers can be processed by melt-spinning to create surgical suture type materials. These melt-spun sutures can have the high tensile strength and durability necessary for wound closure. NO release from the suture can be controlled by application of a biodegradable coating. In this work, an acrylonitrile- co -1-vinylimidazole (AN/VIM) copolymer was melt-spun and coated with PCL. The coated suture fibers were studied for NO storage and release. Addition of a PCL coating significantly slows release of the NO compared to the uncoated AN/VIM suture. Over 24 h, the coated suture released 46 (±12) µmol NO/g AN.

Semifluorinated polymers incorporating π-conjugated segments diphenylbithiophene and a distyrylbenzene derivative as chromophoric main chain subunits have been prepared via a transition metal-free polymerization technique, and explored as anion sensors. One polymer exhibits visually identifiable colorimetric changes and photoluminescence enhancement in response to fluoride or cyanide over other common anions such as OAc − , P 2 O 7 4− , Cl − , Br − , I − , PO 4 3− , or HSO 4 − in THF. Modest dissociation constants of 4.5 × 10 −5 M and 6.7 × 10 −3 M were determined for binding of fluoride and cyanide, respectively, to the most responsive polymer.

Perfluorocyclobutyl (PFCB) aryl ether polymers have various applications in the field of optics due to their synthetic versatility and availability, solution and melt processability, high temperature and photo stability, excellent optical transparency. Nanoparticle matrix materials, encapsulants, and chemical sensors are just a few examples of recent developments.

High molecular weight perfluorocyclobutyl-containing polybenzimidazoles (PFCB–PBI) were synthesized from 4,4′-((1,2,3,3,4,4-hexafluorocyclobutane-1,2-diyl)bis(oxy))dibenzoic acid (PFCB diacid) and 3,3′,4,4′-tetraaminobiphenyl (TAB) in phosphorous pentoxide/methanesulfonic acid (PPMA). PPMA was used as a reaction medium to replace PPA due to the higher monomer solubility. High molecular weight polymer was achieved via optimization of the monomer/solvent ratio, polymerization temperature, and polymerization time. The resulting polymer showed good thermal and chemical stability. Several different phosphoric acid doping membrane preparation processes were investigated. Conventional DMAc solvent casting and direct-casting of the PBI/PPMA solution did not produce sufficiently strong membranes to fabricate into MEAs. A modified PPA process was developed that produced improved membranes. The mechanical properties of these membranes were low compared to other PBI membranes; however, they were sufficiently strong to fabricate into membrane electrode assemblies and tested in single cell fuel cells under various conditions. The polymer dissolved in phosphoric acid at temperatures above 140 °C, which limited the operation of fuel cells below 140 °C. The maximum power densities of fuel cells operated with these membranes were similar to meta-PBI membranes prepared by the conventional casting process and lower than para-PBI membranes prepared by the PPA process.

New fluorinated arylene vinylene ether (FAVE) polymers were prepared by a facile, metal-free condensation polymerization of fluorene, phenylenevinylene, dithiophene, or thiadiazole chromophore-containing bisphenols with bis(trifluorovinyloxy)biphenyl. The addition of chromophores encapsulated into the polymers were prepared in good yields and characterized by 1H and 19F NMR and GPC. Thermal analysis by differential scanning calorimetry (DSC) confirmed the polymers are entirely amorphous and are easy to solution process, producing optically transparent, flexible films. Thermal gravimetric analysis (TGA) showed they possess high thermal stability with decomposition temperatures of 340−387 °C and 308−443 °C in nitrogen and air, respectively. Chromophore inclusion was confirmed by ultraviolet−visible (UV−vis) spectroscopy, which demonstrated tailorable photoluminescence (PL) in both the solution and the solid state by selective substitution of the chromophore. Polymer thin film PL studies revealed notable red...

4-(Trifluorovinyloxy)benzaldehyde was treated under Wittig conditions with 4-dihexyloxy-2,5-xylenebis(triphenylphosphoniumbromide) to form 1,4-bis(2′-(4-trifluorovinyloxyphenyl)ethenyl)-2,5-dihexyloxybenzene, a novel phenylene vinylene-bistrifluorovinyl ether monomer. Cyclopolymerization afforded an insoluble, non-luminescent material likely due to cross-addition reactions between phenylene vinylene olefin and trifluorovinyl ether (TFVE). However, 1,2-bis(4-formylphenoxy)hexafluorocyclobutane was polymerized with 1,4-dihexyloxy-2,5-xylenebis(triphenylphosphoniumbromide) and 1-methoxy-4-(2-ethylhexyloxy)-2,5-xylenebis(triphenylphosphoniumbromide) under Wittig conditions to yield two novel poly(perfluorocyclobutyl- co -phenylene vinylene) polymers. The polymers are of moderate molecular weight (8600–8700 M n ), show excellent thermal stability ( T d = 390–405 °C), and are readily soluble in common organic solvents. The materials are highly fluorescent in both solution and thin film with solution quantum yields of 68 and 71%.

International audience; Post functionalization of aryl ether perfluorocyclobutyl (PFCB) polymers with fluoroalkyl side chains was accomplished with Umemoto's FITS reagents. The fluoroalkylated PFCB polymers (20 % functionalized) showed increases in both hydrophobicity and oleophobicity. Static contact angle for hexadecane was increased after fluoroalkylation from 0° to greater than 30° for the two PFCB polymers tested. Increased oil repellency makes these materials potential candidates for various coatings applications.

A novel approach to property enhancement of poly(l-lactic acid) (PLLA) through the use of perfluoropolyether (PFPE) enchainment is described. Segmented copolymers (FluoroPLA) exhibit tailored surface properties with reasonably high molecular weights and low polydispersities compared to PLLA alone using standard ring-opening polymerization procedures in the presence of tin catalysts. Low loadings of PFPE content (ca. 1−5 wt %) decreases surface energies compared to PLLA from 35 to 38 to 15−18 mN/m2, similar to values reported for poly(tetrafluoroethylene). Ultimate strain studies of FluoroPLA fibers and films have shown a dramatic increase (>300% elongation) over PLLA. This new class of polymer may further expand the use of renewable resources in a variety of applications such as flame retardants, chemical resistant fibers and/or fabrics with tailorable surface energies and wetting properties.

Versatile intermediates 4-bromo(trifluorovinyloxy)benzene or 4-trifluorovinyloxyphenylboronic acid pinacol ester undergo a one step Suzuki coupling reaction with commercial aryl diboronic acids or aryl dibromides and afforded three new aryltrifluorovinylether chromophore monomers. The structures of these monomers were confirmed by 1H, 19F, and 13C NMR spectroscopy and elemental (C, H, and N) combustion analysis. The monomers were readily polymerized via thermal [2 + 2] cyclopolymerization to form chromophore containing PFCB polymers with high molecular weights (Mn = 16 700−22 000), superb thermal stability Td > 450 °C, and excellent processability. Photoluminescence studies reveal that the fluorinated ether linkage has no effect on lumiphore emission wavelength or solution quantum yields. Copolymerization affords a facile route to tailored emission from a linear polymeric system that includes a broad range of the visible spectrum. The properties of these polymers were analyzed by differential scanning cal...

A new semi-fluorinated perfluorocyclobutyl (PFCB) aryl ether containing polymer was prepared in high yield via the condensation of a commercial 4,4'-((1,2,3,3,4,4-hexafluorocyclobutane-1,2-diyl)bis(oxy))bisphenol (bisphenol T) and bis(trifluorovinyloxyether)biphenyl producing transparent, flexible films. The polymer system was structurally characterized using 1H and 19F NMR and exhibited a high degree of thermal stability as determined by thermogravimetric analysis capacity. The sulfonated analogue showed the highest degree of sulfonation at 27% from ion-exchange chromatography, producing a conductivity of 0.011 S cm-1 at 100% relative humidity.

High-pressure phase behavior data reported here demonstrate the nuanced impact fluorine exerts on polymer solubility in supercritical fluid solvents. Copolymers are used that contain a perfluorocyc...

This study focuses on the preparation, polymerization, characterization, and optical properties of a new bis-(4-trifluoromethanesulfonyloxyphenyl)phenylamine monomer. This is the first nitrogen-containing monomer having nitrogen atoms as bridges between phenyl rings, and it was synthesized in three steps. The polymerization was carried out through the Ni(0)-catalyzed homocoupling reaction of the bis-(4-trifluoromethanesulfonyloxyphenyl)phenylamine compound. The resulting polymer, polybis(paraphenyl)phenylamine, emitted an intense blue color (where λ = 415 nm) upon irradiation by ultraviolet light. The photoluminescence quantum yield was found to be 36% with a long excited-state lifetime of 3.3 ns. Electrical conductivity data for an HCl-doped film of the polymer were also examined. This novel polymer is of interest as an organic emitting material for electroluminescent devices.

Bis-ortho-diynylarene (BODA) monomers, prepared from common bisphenols in three high yielding steps, undergo free-radical-mediated thermal polymerization via an initial Bergman cyclo-rearrangement. Polymerization is carried out at 210 °C in solution or neat with large pre-vitrification melt windows (4-5 h) to form branched oligomers containing reactive pendant and terminal aryldiynes. Melt- and solution-processable oligomers with weight-average molecular weight M w = 3000-24 000 g mol -1 can be coated as a thin film or molded using soft lithography techniques. Subsequent curing to 450 °C affords network polymers with no detectable glass transition temperatures below 400°C and thermal stability ranging from 0.5-1.5 % h -1 isothermal weight loss measured at 450°C under nitrogen. Heating to 900-1000 °C gives semiconductive glassy carbon in high yield. BODA monomer synthesis, network characterization and kinetics, processability, thin-film photoluminescence, and thermal properties are described.

In situ copolyesters containing polylactide (PLA) and polyhydroxyalkanoate (PHA) segments were obtained via ring-opening polymerization of L-lactide using PHA as a macroinitiator with stannous octoate as catalyst. Incorporation of PHA (20 wt %) into PLA affords a novel copolymer with Mn values ranging from 25 to 50 KDa and low polydispersities of 1.8-2.3. DSC analysis of the copolymer indicates well-defined crystallization and melting transitions different from the homopolymers and corresponding blend. The polymers were characterized by FT-IR, GPC, DSC, optical microscopy, NMR, and TGA. The results show successful reactivity of PHA as a macroinitiator for the ring-opening polymerization of lactide.

The preparation, fabrication, and carbonization of bis-ortho-diynylarene (BODA)-derived polymers are described. BODA monomers undergo thermal step-growth polymerization to reactive and processable branched polyarylene intermediates. Well-defined intermediates with controlled conversion, molecular weight and viscosity, along with solution or melt processing allow for control in ultimate carbon structure. Fabrication followed by thermal cure and carbonization results in solid or hollow carbon fiber prototypes with interesting thermal and electrical properties. The BODA polymerization and fiber formation were investigated by differential scanning calorimetry, and gel permeation chromatography. The thermal behavior and stability of fibers was measured by thermogravimetric analysis. The surface crystallinity of fibers was studied by Raman spectroscopy. The conductivity of fibers was measured by a multimeter. The surface morphology and dimensions of the fibers were examined by scanning electron microscopy.

Multilayer fullerenes (carbon nano-onions, CNOs) represent a largely unexplored carbon allotrope due to their inherent insolubility. Expectations are that the properties of these nano-onions will be unique and potentially useful, as has been the case with the fullerenes and carbon nanotubes (CNTs). CNOs show diminished chemical reactivity; however, the established thermal diradical formation and reactivity of bis-o-diynyl arene (BODA) monomers afforded direct functionalization, solution processing, and de-functionalization of CNOs; and the first example of a radical addition of a conjugated polymer to CNOs. The functionalized and soluble CNOs were characterized by TEM, GPC, TGA, Raman spectroscopy, and XPS. A CNO defunctionalization method using oxidative TGA is also presented.

The thermal cyclopolymerization of three trifluorovinyl aromatic ether monomers 1,1,1-tris (4-trifluorovinyloxyphenyl)ethane (1), 4,4′-bis(4-trifluorovinyloxy)biphenyl (2) and 2,2-bis(4-trifluorovinyloxy- phenyl)-1,1,1,3,3,3-hexafluoropropane (3) were monitored in situ using time-resolved electron paramagnetic resonance spectroscopy over a temperature range of 150–210 °C. The signals observed during the early stages of perfluorocyclobutyl polymer production suggest the formation of a triplet state corresponding to the proposed biradical intermediate with a strong dipole–dipole interaction. A doublet splitting shows the presence of hyperfine coupling due to fluorine. The characterization of radical species formed during the polymerization of monomer 1 using model compounds and polymerization kinetics of monomer 2 are also presented. Copyright © 2007 Society of Chemical Industry

The objective of this study was to illustrate how submicrogratings can be prepared from bis-ortho-diynylarene (BODA)-derived polymers. BODA monomers undergo thermal step-growth polymerization and careful control of this conversion, with respect to molecular weight and viscosity, can be used to produce reactive, processable branched polyarlyene intermediates. “Soft-lithography” techniques were used to prepare submicrogratings from these intermediates, which were subsequently stabilized by further polymerization. The surface morphology and dimensions of the submicrogratings were examined using scanning electron microscopy techniques and crystallinity was studied. Reflectivity data was also obtained from linear submicrogratings. These BODA-derived microstructures can be carbonized at 1000°C, or above, to obtain carbonized microstructures with potential for application in optical and electronic microdevices. POLYM. ENG. SCI., 47:2095–2099, 2007. © 2007 Society of Plastics Engineers

New thermally cross-linkable and/or post-functionalizable perfluorocyclobutyl (PFCB) polymers containing Meldrum's acid moieties have been successfully prepared via the thermal cyclopolymerization of a new Meldrum's acid functionalized aromatic trifluorovinyl ether (TFVE) monomer.

This study focuses on the preparation, characterization, and optical properties of new bis(3,4-diphenylethynylphenyl)phenylamine. This is the first nitrogen-containing bis-ortho-diynylarene (BODA) monomer having a nitrogen atom as the spacer group. BODA monomers are usually prepared from common bisphenols, thereby providing great synthetic versatility and the opportunity to develop a wide array of novel polyarylene thermosets by varying the aromatic spacer group. The new bis(3,4-bisphenylethynylphenyl)phenylamine was synthesized in five steps. This compound emits an intense blue color (λ = 438 nm) upon irradiation by UV light and may be suitable for use as an emitting layer in electroluminescent devices. Bis-(3,4-bisphenylethynylphenyl)phenylamine and its polymer have photoluminescence quantum yields 34 and 38%, respectively, and long excited-state lifetimes of 3.2 and 3.6 ns, respectively. The structure of the monomer and its polymer were characterized using spectroscopic techniques including Ultraviolet–visible Spectrophotometer, Photoluminescence Spectrophotometer, Fourier Transform infrared spectroscopy, and Gel Permeation Chromatography. The polymerizations were studied by Differential Scanning Calorimeter. The amount of weight loss and the thermostability of the nitrogen-containing polymer were determined from thermogravimetric analysis. The electrical conductivity of neat HCl-doped BODA-derived polymer film was measured according to the standard four-point probe technique. © 2006 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 44: 6988–6996, 2006

An alternative fluoropolymer and carbon composite materials approach for proton exchange membrane (PEM) applications is reviewed based on non‐PFSA polymers derived from unique trifluorovinyl ether (TVE) compounds. Radical polymerization and copolymerization of perfluoroalkyl TVE monomers give perfluoroalkylsulfonyl imide ionomers which behave similarly to Nafion™ membranes, yet demonstrate higher acidity and greater stability. Aromatic TVE monomers incorporating the perfluoroalkylsulfonimide functionality undergo thermal step‐growth polymerization to perfluorocyclobutyl (PFCB) polymers and unique ionomers. PFCB containing sulfonated polyarylene ether sulfone ionomers, as well as directly sulfonated PFCB polymers have been synthesized in a prefunctionalization method. Designed carbon/fluoropolymer composite electrodes with porous architectures and covalently attached fluoropolymers are also reviewed.

Department of Chemistry, School of Materials Science andEngineering and Center for Optical Materials Science andEngineering Technologies (COMSET), Clemson UniVersity,Clemson, South Carolina 29634-0973, and Department ofPhysics, Kent State UniVersity, Kent, Ohio 44242ReceiVed March 6, 2006ReVised Manuscript ReceiVed May 17, 2006Introduction. Poly(p-phenylene)s (PPP) are highly extendedlinear macromolecules due to their rigid structure, and as a result,unmodified PPP is an insoluble and intractable material.

Three phenylphosphine oxide (PPO) containing trifluorovinyl aryl ether monomers were synthesized and polymerized via thermal cyclodimerization affording perfluorocyclobutyl (PFCB) polymers containing PPO pendent groups. The new polymers exhibited moderate to high glass transition temperatures (Tg=145–217 °C) and good thermal stability in nitrogen (5% weight loss, Td>402 °C). Copolymerization with traditional PFCB forming monomers such as 4,4′-(trifluorovinyloxy)biphenyl resulted in film forming transparent thermoplastic copolymers with improved solubility and further enhanced thermal stability. Semi-fluorinated PPO containing polymers of this type may find potential application as space environment durable materials.

The synthesis and thermal cyclopolymerization of aryl trifluorovinyl ether monomers containing novel sulfonimide acid functionalities are described. The monomers are prepared starting from commercially available 4-bromophenol in five steps. These novel polymers explore a new versatile class of partially fluorinated polymers for potential use in fuel cells and other electrochemical applications.

Three different supercritical fluids (SCF), CO2, dimethyl ether (DME), and propane, are investigated as potential solvents for processing two lactide-based terpolymers and two perfluorocyclobutyl (PFCB) aryl ether polymers. The repeat unit of the lactide-based terpolymers consists of a 1:1:1 ratio of L-lactide, diglycidyl ether of bisphenol A (DGEBA), and, in one case, 4,4′-hexafluoroisopropylidenediphenol (6F-Bis-A) and, in the other case, 4,4′-isopropylidenediphenol (6H-Bis-A). The PFCB-based polymers are synthesized from 1,1-bis[4-[(trifluorovinyl)oxy]phenyl]hexafluoroisopropylidene (6FVE) and from bis(trifluorovinyloxy)biphenyl (BPVE). For both classes of polymer the steric effect of the hexafluoroisopropylidene (6F) group reduces chain–chain interactions, disrupts electronic resonance between adjacent aromatic groups, and improves solubility. The two lactide-based terpolymers do not dissolve in CO2 or propane, but dissolve in DME. At room temperature the poly(lactide 6F-BisA DGEBA) terpolymer dissolves at 700 bar lower pressure in DME compared to the poly(lactide 6H-Bis-A DGEBA) terpolymer. Although the 6FVE polymer dissolves in all three SCF solvents, pressures in excess of 800 bar are needed to dissolve this polymer in CO2 and propane while 6FVE dissolves in DME at pressure below 150 bar. The other PFCB-based polymer (BPVE) only dissolves in DME, again at low pressure, although BPVE drops out of solution as the system temperature is raised above ∼40°C, whereas 6FVE remains in solution in DME for temperatures up to 90°C. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 97: 1736–1743, 2005

Oligoethylene-end-capped polylactides were synthesized through the ring- opening polymerization of L-lactide with alcohol-terminated oligoethylenes as macro- initiators. The polymerization of L-lactide was carried out in bulk at 130 8C in the presence of stannous octoate and primary alcohols with four different molecular weights: 350, 425, 550, and 700 g/mol. The end-capped copolymers that formed had a number-average molecular weight of approximately 40,000 (weight-average molecular weight/number-average molecular weight ¼ 1.7) according to gel permeation chroma- tography and were highly crystalline in comparison with the similarly formed homo- polymer of L-lactide. The copolymer structure was characterized by Fourier transform infrared, NMR, matrix-assisted laser desorption/ionization time-of-flight mass spec- trometry, and differential scanning calorimetry analysis. This work focused on devel- oping more crystallizable and hydrolytically stable polylactide derivatives that could potentially be used as compatibilizers in polylactide-polyolefin blends or as nucleat- ing agents for poly(L-lactide) or other polyesters. V C 2005 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 43: 5257-5266, 2005

The thermal cyclopolymerization of 2,2-bis(4-trifluorovinyloxyphenyl)-1,1,1,3,3,3-hexafluoropropane affords the first example of a semi-crystalline perfluorocyclobutyl (PFCB) polymer and an anomalous feature for a polymer containing the hexafluoroisopropylidene (6F) linkage. Fluoroalkylation of 2,2-bis(hydroxyphenyl)-1,1,1,3,3,3-hexafluoropropane (6F bisphenol A) with 1,2-dibromotetrafluoroethane, followed by zinc mediated elimination affords the bis(trifluorovinyloxyphenyl) monomer in good yield. High molecular weight polymer (Mw=66,700) with molecular weight distribution approaching 2 was obtained by heating neat monomer at 180 °C for 24 h and 220 °C for 8 h. The stereo-random polymer (ca. 48 to 52 cis- to trans-1,2-disubstituted perfluorocyclobutyl groups) is easily crystallized from the melt despite the presence of the 6F group and a substantial increased fluorocarbon content per repeat unit compared to traditional PFCB polymers. A melting temperature approaching 200 °C was measured by DSC and the crystallinity was characterized by WAXD. Remarkably, the high melting semi-crystalline polymer could be easily dissolved in common solvents in greater than 50 wt% solutions.

Summary: The synthesis and polymerization of novel 18-crown-6 and 24-crown-8 bis aryl trifluorovinyl ethers is described. Thermally induced polymerization yields linear crown ether fluoropolymers with hexafluorocyclobutyl linkages. The polymers exhibit Tg's above 120 °C and show good thermal stability with no appreciable weight loss below 350 °C. Incorporation of crown ether macrocycles into the polymer is expected to increase cationic uptake of an otherwise electroneutral fluoropolymer.

A novel aryl trifluorovinyl ether monomer, 1,1,1-tris(4-trifluorovinyloxy-phenyl)-2,2,2-trifluoroethane (5), was prepared via a multistep reaction sequence adapted from previously reported procedures. Monomer 5 polymerizes by free-radical mediated thermal cyclodimerization to produce a crosslinked perfluorocyclobutyl (PFCB) polymer. Substituting CH 3 for CF 3 did not affect the polymerization kinetics as measured by differential scanning calorimetry. Surprisingly, the refractive index of poly5 (1.4931 at 1550 nm) is slightly higher than that measured for poly6 (1.4876 at 1550 nm) despite the significant increase in fluorine content. Compared to the CH 3 -containing monomer 6, fluorinated analogue 5 exhibits increased thermal and thermal oxidative stability and thus we expected lower optical loss for long-term high performance applications. Copolymerization with existing aryl trifluorovinyl ether monomers should allow access to new PFCB network copolymers with a tailored performance.

A novel class of phenylphosphine oxide (PPO) containing perfluorocyclobutyl (PFCB) polymers has been developed for potential use as multifunctional materials in space environments. The reaction of p-BrArOCFCF2 (for Ar = phenyl and biphenyl) with tert-butyllithium affords the lithium reagent smoothly below −20 °C. Subsequent substitution with phenylphosphonic dichloride provides the first bis(trifluorovinyl ether) monomers containing the PPO group. Polymerization proceeds thermally above 150 °C to give polymers that exhibit glass transition temperatures of 169 and 224 °C, respectively, and catastrophic weight loss by TGA in N2 and air above 450 °C (10 °C/min). Copolymerization with bis(4,4‘-trifluorovinyloxy)biphenyl affords film-forming transparent thermoplastic copolymers with high Tg (>140 °C) and good thermal stability (>450 °C). Initial evaluations with ground-based simulation of atomic oxygen (AO) rich space environments indicate that the PPO group imparts significant space durability to PFCB polymers.

4-Bromotrifluorovinyloxybenzene (4-Br-TFVE) undergoes cyclodimerization upon heating at 150 °C affording cis and trans isomers of 1,2-bis(4-bromophenoxy)hexafluorocylcobutane. Stereoisomers were separated by selective crystallization, confirmed by single crystal X-ray, and further characterized by NMR. Remarkable difference in the solid state structures include aryl to aryl dihedral angles of 12° for the trans isomer and 88° for the cis isomer. Polymers containing roughly equal amounts of cis and trans fused perfluorocyclobutyl (PFCB) rings should be expected to have low crystallinity due to the marked difference in the two unit cells as is observed.