High glass transition and thermally stable polynorbornenes containing fluorescent dipyrene moieties via ring‐opening metathesis polymerization

A high‐glass‐transition‐temperature polynorbornene, poly(NBEDPY), containing chromophore groups was synthesized by ring‐opening metathesis polymerization (ROMP) using Grubbs' catalysts; poly(HNBEDPY) was obtained by the reduction of poly(NBEDPY). The glass transition temperatures (T_g) of poly(NBEDPY) and hydrogenated poly(HNBEDPY) were as high as 250 °C and 220 °C, respectively, because of the rigid dipyrene groups, which are higher than those of commercially available ring‐opened hydrogenated polynorbornenes (JSR ARTON®; 120–165 °C). The 10% weight‐loss temperatures of hydrogenated poly(HNBEDPY) and poly(NBEDPY) were up to 450 °C and 400 °C, respectively. A hydrogenated poly (HNBEDPY) film showed excellent transparency (over 91%). The photoluminescence emission spectra of poly(HNBEDPY) showed strong solvent‐polarity dependence, revealing that poly (HNBEDPY) underwent remarkable bathochromic shifts with an increase in solvent polarity. Poly(HNBEDPY) also showed remarkable fluorescent solvatochromism (blue in toluene, greenish yellow in dimethyl sulfoxide). The cyclic voltammogram of poly(HNBEDPY) film cast onto an indium tin oxide (ITO)‐coated glass substrate exhibited one reversible oxidation redox couple at 0.55 V versus Ag/Ag⁺ in acetonitrile solution. The electrochromic characteristics of poly(HNBEDPY) showed reversibility, with a color change from its green neutral form to dark red upon the application of potentials from 0 to 1.0 V. © 2011 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2011     

Preparation of neutrally colorless,transparent polynorbornenes with multiple redox‐active chromophores via ring‐opening metathesis polymerization toward electrochromic applications

A new electrochromic norbornene derivative containing triphenylamine groups (NBDTPAC8) was synthesized using norbornene amine and bromotriphenylamine. NBDTPAC8 was used in ring‐opening metathesis polymerization to obtain poly(NBDTPAC8) using different Grubbs' catalysts and followed by hydrogen reduction to obtain poly(HNBDTPAC8). The glass transition temperatures (T_g) of poly(NBDTPAC8) and hydrogenated poly(HNBDTPAC8) were 132 and 89 °C, respectively. Poly(HNBDTPAC8) film exhibited a fluorescence maximum around 416 nm with a quantum yield of up to 60%. Hydrogenated poly(HNBDTPAC8) film showed excellent transparency (up to 93%). Poly(HNBDTPAC8) showed cyclic voltammetric and electrochromic behaviors similar to those of poly(NBDTPAC8). The cyclic voltammogram of a poly(HNBDTPAC8) film cast onto an indium tin oxide (ITO)‐coated glass substrate exhibited three reversible oxidation redox couples at 0.69, 0.94 and 1.38 V versus Ag/Ag⁺ in an acetonitrile solution. The electrochromic characteristics of poly(HNBDTPAC8) showed excellent stability and reversibility, with multi‐staged color changes from its colorless neutral form to green, light blue and dark blue upon the application of potentials ranging from 0 to 1.60 V. The color switching time and bleaching time of the poly(HNBDTPAC8) film were 6.2 s and 4.3 s at 1175 nm and 6.6 s and 4.4 s at 970 nm, respectively. © 2011 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2011.     

Novel organosoluble polynorbornene bearing a polar,pendant, ester‐bridged epoxy group via living ring‐opening metathesis polymerization

A novel organosoluble polynorbornene bearing a polar, pendant, ester‐bridged epoxy group [poly(oxiran‐2‐ylmethyl 2‐methylbicyclo[2.2.1]hept‐5‐ene‐2‐carboxylate) (polyOMMC)] was prepared via the living ring‐opening metathesis polymerization (ROMP) of active norbornenes with a Ru catalyst. PolyOMMC exhibited excellent solubility in a variety of solvents. The number‐average molecular weight of polyOMMC linearly increased with the [M]/[I] ratio (where [M] is the monomer concentration and [I] is the initiator concentration), and a narrow polydispersity of 1.09–1.19 was observed; this was considered a living polymerization. When ROMP of oxiran‐2‐ylmethyl 2‐methylbicyclo[2.2.1]hept‐5‐ene‐2‐carboxylate with [M]/[I] = 350 was carried out at 30 °C in CH₂Cl₂, the number‐average molecular weight (7.01 × 10⁴; polydispersity index = 1.07) was close to the calculated molecular weight (7.28 × 10⁴), and a diblock copolymer was observed after the addition of another monomer ([M]/[I] = 350) with an increase in the number‐average molecular weight (1.60 × 10⁵; polydispersity index = 1.11), which was close to the calculated molecular weight (1.61 × 10⁵). The modified polynorbornenes retained good solubility in methylene chloride, tetrahydrofuran, dimethyl sulfoxide, dimethylformamide, N,N‐dimethylacetamide, and N‐methyl‐2‐pyrrdione. High‐performance polynorbornenes with active epoxy groups could be designed with great potential for applications in photoresists, UV curing, and elastomers. © 2006 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 44: 4428–4434, 2006     

Polymeric microstructures and dielectric properties of polynorbornenes with 3,5‐bis(trifluoromethyl)biphenyl side groups by ring‐opening metathesis polymerization

exo‐Polynorbornenes containing bis(trifluoromethyl)biphenyl side groups were synthesized by ring‐opening metathesis polymerization using different Grubbs' catalysts, the microstructures of the polymer chains were established using NMR and IR spectroscopy. The influence of monomer and catalyst structures on chain microstructure was revealed and the correlation of properties with microstructure was investigated in detail. The exo‐poly(N‐3,5‐bis(trifluoromethyl)biphenyl‐norbornene‐pyrrolidine) (exo‐PTNP) and exo‐poly(N‐3,5‐bis(trifluoromethyl)biphenyl‐norbornene‐dicarboximide) (exo‐PTNDI) formed using Ru‐I show a trans double bond bias of 67% and 83%, respectively, whereas the corresponding polymers formed using Ru‐III have lower contents of trans double bond, 30% and 50%, respectively. Compared to the highly trans endo‐PTNP formed using Ru‐I , which is isotactic and has a dielectric constant of about 20, the endo‐PTNP formed using Ru‐III, the exo‐PTNDIs and the exo‐PTNPs formed using Ru‐I and Ru‐III all have different proportions of trans and cis double bonds, they are atactic and display relatively low dielectric constants, in the range 6 to 9. DSC measurements indicate some dependence of T_g, varying 161 to 221 °C, on tacticity and cis/trans ratios with higher trans contents tending towards higher T_g. © 2013 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2013 , 51, 4786–4798     

Degradable precision polynorbornenes via ring‐opening metathesis polymerization

In an attempt to introduce monomer sequence control in a growing polynorbornene via ring‐opening metathesis polymerization, we employ dioxepins to efficiently determine the location of the monomers on the macromolecule backbone. Owing to the acid‐labile acetal group, dioxepins allow scission of the polymer at the point of the dioxepin insertion and thus provide an indirect way to determine the monomer location. Additionally, dioxepins are used as spacers in the synthesis of multiblock polynorbornenes that are readily cleavable to afford the individual polynorbornene blocks. © 2015 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2016 , 54, 1236–1242     

Synthesis of POSS‐terminated polycyclooctadiene telechelics via ring‐opening metathesis polymerization

In this contribution, we reported the synthesis of a series of POSS‐terminated polycyclooctadiene (PCOD) telechelics via ring‐opening metathesis polymerization (ROMP) approach. Toward this end, 1,4‐diPOSS‐but‐2‐ene was synthesized via copper‐catalyzed Huisgen cycloaddition reaction (i.e., click chemistry); it was then used as a chain transfer agent (CTA) for the ROMP of cyclooctadiene. The ROMP was carried out with Grubbs second generation catalyst and the POSS‐terminated PCOD telechelics with variable lengths of PCOD were obtained by controlling the molar ratios of CTA to cyclooctadiene. All the POSS‐terminated PCOD telechelics in bulks were microphase‐separated; the morphologies were quite dependent on the lengths of PCOD midchains. The POSS end groups can promote the crystallization of PCOD chains at room temperature, which was in marked contrast to the case of plain PCOD. Compared to the plain PCOD, the POSS‐terminated PCOD telechelics displayed improved thermal stability and surface hydrophobicity. © 2016 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2017 , 55, 223–233     

Synthesis of norbornenes containing cationic mono‐ and di(cyclopentadienyliron)arene complexes and their ring‐opening metathesis polymerization

A number of classes of polynorbornenes containing cationic iron moieties within their side chains were prepared via ring‐opening metathesis polymerization with a ruthenium‐based catalyst. The iron‐containing polymers displayed excellent solubility in polar organic solvents. The weight‐average molecular weights of these polymeric materials were estimated to be in the range of 18,000–48,000. Thermogravimetric analysis of these polymers showed two distinct weight losses. The first weight loss was in the range of 204–260 °C and was due to the loss of the metallic moieties, whereas the second weight loss was observed at 368–512 °C and was due to the degradation of the polymer backbone. Cyclic voltammetry studies of the iron‐containing polymers showed that the 18 e^? cationic iron centers underwent a reduction to give the neutral 19 e^? complexes at half‐wave potential (E_1/2) = ?1.105 V. Photolysis of the metallated polymers led to the isolation of the norbornene polymers in very good yields. Differential scanning calorimetry studies showed a sharp increase in the glass‐transition temperatures up to 91 °C when rigid aromatic side chains were incorporated into the norbornene polymers. © 2006 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 44: 3053–3070, 2006     

Charge‐transfer piperazine‐containing polymeric systems via ring‐opening metathesis polymerization

This article describes the synthesis of piperazine‐containing homopolymer systems via ring‐opening metathesis polymerization (ROMP). These systems were subsequently used as electron donors in the formation of charge‐transfer (CT) complexes. Using exo‐N‐(6‐bromohexyl)‐7‐oxabicyclo[2.2.1]hept‐5‐ene‐2,3‐dicarboxamide as a starting material, monomers were synthesized to act as electron donors. The amine group at the “open” end of the piperazine was either left open or alkylated with various alkyl groups. The monomers' ability to act as electron donors and their polymerization rates were studied. After initial photometric titration studies using 2,3‐dichloro‐5,6‐dicyanobenzoquinone (DDQ) as an electron acceptor proved that these monomers would act as electron donors, they were subsequently polymerized into homopolymers via ROMP. The experimental results showed that a methanol:chloroform mixed solvent system enhanced the rate of polymerization over a single solvent (chloroform) system. Studies also showed that the alkylated piperazine‐containing monomer had a faster rate of polymerization than the secondary piperazine monomer. These monomers were used to make piperazine‐containing homopolymers via ROMP and the resulting polymers, like the monomers, also functioned as electron donors. Potential functions of these polymers include electronics, solar cells, optical systems, and biological applications. © 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 47: 5034–5043, 2009     

Synthesis of reactive poly(norbornene): Ring‐opening metathesis polymerization of norbornene monomer bearing cyclic dithiocarbonate moiety

A norbornene monomer bearing cyclic dithiocarbonate moiety (NB‐DTC) was successfully synthesized from the corresponding precursor having epoxy moiety by its reaction with carbon disulfide. NB‐DTC underwent the ring‐opening metathesis polymerization (ROMP) catalyzed by a ruthenium carbene complex to give the corresponding poly(norbornene). The dithiocarbonate moiety incorporated into the side chain of the obtained poly(norbornene) reacted with amine to afford the corresponding thiourethane moiety with thiol group, which underwent oxidative S‐S coupling and/or addition reaction to the C‐C double bond in the main chain, leading to formation of a cross‐linked polymer. © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2011.     

Synthesis of phenylenevinylene and naphthylenevinylene homopolymers and block copolymers by ring‐opening metathesis polymerization

Homopolymers and copolymers containing phenylenevinylenes and naphthylenevinylenes can be synthesized by ring‐opening metathesis polymerization of strained monomers such as tetraoctyloxy‐substituted cyclophanedienes and naphthalenophanedienes initiated by the third‐generation Grubbs’ initiator. The resulting homopolymers exhibited low polydispersities. The block copolymers can also be synthesized by the sequential ring‐opening metathesis polymerization of two individual monomers. The structures of homopolymers and block copolymers were fully characterized by nuclear magnetic resonance spectroscopy. The molecular weight distribution of the block copolymers is relatively broad compared to their parent homopolymers possibly due to chain transfer reaction. The molar ratio of the two blocks can be tailored by the ratio of the monomers employed. The block copolymers exhibited a more efficient energy transfer in the solid state between the different blocks than those carried out in solution. The optical and electrochemical properties of the polymers were investigated and exhibited the potential uses in optoelectronics devices. © 2017 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2018 , 56, 67–74     

Norbornene derivatives from a metal‐free,strain‐promoted cycloaddition reaction: New building blocks for ring‐opening metathesis polymerization reactions

The preparation of new ring opening metathesis polymerization (ROMP) monomers using a 1,3‐dipolar cycloaddition between aryl azides and norbornadiene is described. Various norbornenetriazolines, obtained through a solvent‐and catalyst‐free reaction, can subsequently be incorporated into polymer backbones through ROMP reactions. Furthermore, thermal decomposition of the triazoline moiety can allow for further polymer functionalization. © 2015 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2015 , 53, 2357–2362     

Synthesis of laterally attached side‐chain liquid‐crystalline polynorbornenes with high mesogen density by ring‐opening metathesis polymerization

(±)‐exo,endo‐5,6‐Bis{[[11′‐[2″,5″‐bis[2‐(3′‐fluoro‐4′‐n‐alkoxyphenyl)ethynyl]phenyl]undecyl]oxy]carbonyl}bicyclo[2.2.1]hept‐2‐ene (n = 1–12) monomers were polymerized by ring‐opening metathesis polymerization in tetrahydrofuran at room temperature with Mo(CHCMe₂Ph)(N‐2,6‐ⁱPr₂Ph)(O^tBu)₂ as the initiator to produce polymers with number‐average degrees of polymerization of 8–37 and relatively narrow polydispersities (polydispersity index = 1.08–1.31). The thermotropic behavior of these materials was independent of the molecular weight and therefore representative of that of a polymer at approximately 15 repeat units. The polymers exhibited an enantiotropic nematic mesophase when n was 2 or greater. © 2006 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 44: 4076–4087, 2006     

Synthesis of polybutadiene‐based particles via dispersion ring‐opening metathesis polymerization

Latex particles based on 1,4‐polybutadiene were synthesized via dispersion ring‐opening metathesis copolymerization of 1,5‐cyclooctadiene with a α‐norbornenyl poly(ethylene oxide) macromonomer. Stable but polydisperse colloidal dispersions in the 50 nm to 10 μm size range were obtained. In this work, particular attention was paid to the effects of the kinetics of copolymerization on the structure of the graft copolymers formed and on the onset of turbidity. Strategies to prepare monodisperse polybutadiene particles were also designed through the growth of a polybutadiene shell from a well‐defined polynorbornene seed. © 2004 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 42: 1154–1163, 2004     

High dielectric performance of tactic polynorbornene derivatives synthesized by ring‐opening metathesis polymerization

Functional polynorbornenes (PNBEs) containing pyrrolidine moiety and bis(trifluoromethyl)biphenyl side group were synthesized via ring‐opening metathesis polymerization (ROMP), and the microstructure of polymer chain was characterized by NMR spectroscopy. Poly(N‐3,5‐bis(trifluoromethyl)biphenyl‐norbornene‐pyrrolidine) (PTNP) and poly(N‐phenyl‐norbornene‐pyrrolidine) (PPNP) are supposed to have practically trans double bonds and adopt isotactic syn conformation, whereas poly(N‐3,5‐bis(trifluoromethyl)biphenyl‐norbornene‐dicarboximide) (PTNDI) has both trans and cis double bonds and atactic microstructure. PTNP, PTNDI, and PPNP have much different dielectric constants of 20, 7, and 3, respectively, which is attributed to both the polar 3,5‐bis(trifluoromethyl)biphenyl group and the stereoregular chain structure. The existence of rigid pyrrolidine moiety has a positive contribution to form the tactic polymer chain during ROMP. Polymers are highly thermal stable up to ～300 °C. Having good dielectric properties and thermal stability, these functional PNBEs are expected as the potential dielectric material in thin film capacitors. © 2012 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2013     

Synthesis and characterization of functional polyethylene with regularly distributed thioester pendants via ring‐opening metathesis polymerization

Four kinds of functional polyethylene carrying thioester pendants were synthesized via ring‐opening metathesis polymerization (ROMP) of alkyl cyclopent‐3‐enecarbothioate catalyzed by a ruthenium‐based commercial catalyst and subsequent hydrogenation of the ROMP products (alkyl = ethyl, n‐butyl, n‐octyl, or n‐dodecyl). In these polymers the pendant alkyl thioester groups are precisely distributed along the backbone on every five methylene carbons. Chain structure, molecular weight and molecular weight distribution of the polymers were characterized by ¹H and ¹³C NMR, and GPC. The ROMP reactions all reached high monomer conversions, and hydrogenation of the ROMP products were exhaustive. Thermal transitions and side chain crystallization behaviors of the polymer were investigated and characterized by DSC and TGA. Glass transition temperature and melting temperature of these polymers were higher than the counterparts containing ester pendants. TGA analysis indicated that all the thioester‐containing polymers exhibited moderate thermal stability, and the sulfur‐containing polymers show slightly lower thermal stability than their counterparts without sulfur. The new family of functionalized polyethylenes could be used as models of ethylene‐thioacrylate copolymers, and find applications as novel functional materials. © 2017 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2017 , 55, 4027–4036     

Synthesis of acid‐sensitive latices by ring‐opening metathesis polymerization

This study describes the synthesis of polynorbornene colloidal particles able to release active molecules in response to pH change. Such functionalized polynorbornene latices with surface active molecules have been obtained by ring‐opening metathesis copolymerization in a dichloromethane/ethanol medium in the presence of α‐norbornenyl poly(ethylene oxide) macromonomer. Two different strategies of introduction of the active molecule—either at their periphery or at their core— have been contemplated. The particles have been characterized by both dynamic light scattering and transmission electron microscopy. Their size was found to range from 260 to 600 nm. The release of the active molecules was monitored by UV spectrometry. After 48 h in an appropriate HCl buffer (pH = 3) more than 80% of the initially linked active molecule was released. © 2004 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 43: 217–229, 2005     

Functional benzoxazines containing ammonium salt of carboxylic acid: Synthesis and highly activated thermally induced ring‐opening polymerization

1,3‐Benzoxazine monomers having ammonium salt of carboxylic acid have been developed. These 1,3‐benzoxazines 1a and 1b were easily synthesized from the corresponding tetrabutylammonium salts of glycine and β‐alanine, respectively. The glycine‐derived benzoxazine 1a exhibited remarkably high reactivity, which allowed its thermally induced ring‐opening polymerization in bulk at 100 °C, at which N‐methyl‐1,3‐benzoxazine 1d did not undergo the polymerization at all. © 2011 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2011