Metathesis cyclopolymerization of substituted 1,6‐heptadiyne and dual conductivity of doped polyacetylene bearing branched triazole pendants

The branched triazole group is synthesized by click chemistry via a controlled approach of slow addition of AB₂ compound to a B₂ core, and used as the substituent for 1,6‐heptadiyne monomer. Metathesis cyclopolymerization of monomer is performed well in dichloromethane without the weakly coordinating additive, indicating that the branched triazole itself can stabilize the living propagating chain, to generate branched triazole pendant‐contained polyacetylene with trans‐double bonds and five‐membered ring repeating units along the conjugated backbone. The LiTFSI doped polyacetylenes display ionic conductivities of 2.5–1.8 × 10^?6 S cm^?1; by further doping with iodine, polyacetylenes show the improved ionic and electronic conductivities of 1.3 × 10^?5 and 2.1 × 10^?7 S cm^?1 at 30 °C, respectively. Therefore, these doped polyacetylenes may act as the new electrolyte materials. © 2016 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2017 , 55 , 485–494     

Synthesis,electrolyte properties and solar cell performance of hyperbranched poly(aryl-ether-urea)s

Hyperbranched poly(aryl-ether-urea)s with phenyl, N,N-dimethylamino ethyl and polyethylene oxide end-groups linked through urethane group – HBPEU-1, HBPEU-2 and HBPEU-3 respectively – were synthesized from an AB₂-type blocked isocyanate monomer and characterized by FT-IR, ¹H-NMR, SEC-MALLS, TGA and DSC techniques. The molecular weight of the polymers were found to be ranged from 4.9 × 10³ ? 1.96 × 10⁴ g/mol. The TGA results showed that the polymers decompose between 175°C – 220°C. In the DSC curves, HBPEU-1 and HBPEU-3 showed T_g at 160°C and 53°C respectively, whereas HBPEU-2 did not showed clear T_g. All the three polymers were converted into polymer electrolytes by doping with LiI/I₂. The doped polymers showed remarkably high ionic conductivity, up to 222 – 277 times compared to the un-doped polymers and the highest conductivity was observed with doped HBPEU-2. The TiO₂ based dye-sensitized solar cells (DSSCs) were fabricated using the doped polymer electrolytes and their performance was tested; HBPEU-2 showed good performance by yielding energy conversion efficiency (η) of 4.5%.     

Permeation of oxygen dissolved in water through substituted polyacetylene membranes

The permeation of oxygen dissolved in water through substituted polyacetylene membranes was studied by using an oxygen electrode at 25°C. Many of the membranes (thickness about 200 μm) showed high apparent permeability coefficients P in the range 10^?9?10^?8 cm³ (STP) cm cm^?2s^?1 cmHg^?1. The resistance r of the boundary layer and the permeability P_∞, at infinite membrane thickness were determined from the dependence of P on membrane thickness. The r values of Si-containing and aliphatic polyacetylenes were usually larger than those of aromatic polyacetylenes. The P_∞, values of Si-containing and aliphatic polyacetylenes agreed closely with the permeability coefficients P_g for gaseous oxygen. In contrast, P_∞ values for aromatic polyacetylenes were larger than P_g values.     

NEW MATERIALS DERIVED FROM POLY(4-HYDROXYSTYRENE) AS LITHIUM BATTERY CELL COMPONENTS

A new class of polyethers has been prepared by the Mitsunobu coupling of poly(4-vinyl phenol), P4VP, with low molecular weight poly(ethylene glycol)methyl ether. These comb-like polymers, having ca. 20–30% residual phenols, were characterized by IR, DSC, and TGA. Results of thermal analysis on the polymers suggest thermal stability to at least 300°C and a glass transition temperature in the range ?30 to ?40°C. Complexes with LiPF₆ gave conductivities of ca. 1 × 10^?5 S/cm at room temperature. The polymers were blended with plasticized poly(vinylidene fluoride) (PVDF) to prepare porous films and subsequently infiltrated with lithium salts and ethylene and ethyl methyl carbonate. Ionic conductivities of these hybrid films were measured from ?20°C to 40°C. Conductivities as high as 2.4 × 10^?3 S/cm are observed at room temperature. The electrochemical stability of hybrid materials was studied by cyclic voltammetry.     

Synthesis and characterization of novel polybenzimidazoles bearing pendant phenoxyamine groups

A novel aromatic diacid, 3, 5‐dicarboxyl‐4′‐amino diphenyl ether, containing pendant phenoxy amine group was synthesized. Homo‐ and co‐polybenzimidazoles containing different content of pendant phenoxyamine groups were synthesized by condensation of 3,3′‐diaminobenzidine with this acid and a mixture of this acid and isophthalic acid in different ratio in polyphosphoric acid. Copolybenzimidazoles with structural variations were also synthesized based on this acid and pyridine dicarboxylic acid, terephthalic acid, adipic acid, or sebacic acid. The polymers have good solubility in polar aprotic solvents and strong acids and they form tough flexible films by solution casting. The polymers were characterized by different instrumental techniques (FTIR, TGA, DSC, XRD, etc.) and for solvent solubility, mechanical properties, inherent viscosity, and proton conductivity. The inherent viscosities of the polymers vary in the range of 0.62–1.52 dL/g. They have high thermal stability up to 475–506 °C (IDT) in nitrogen, high glass transition temperatures (T_g) ranging from 313 to 435 °C and good tensile strength ranging from 58 to 125 MPa. Proton conductivity of homo polymer is 3.72 × 10^?3 S/cm at 25 °C and 2.45 × 10^?2 S/cm at 200 °C © 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 5776–5793, 2008     

Unusual effect of molecular weight and concentration on thermoresponsive behaviors of well‐defined water‐soluble semirigid polymers

A series of water‐soluble semirigid thermoresponsive polymers with well‐defined molecular weights based on mesogen‐jacketed liquid crystal polymers (MJLCPs), poly[bis(N‐hydroxyisopropyl pyrrolidone) 2‐vinylterephthalate] (PHIPPVTA) have been synthesized via reversible addition fragmentation chain transfer (RAFT) polymerization. Dynamic light scattering (DLS) revealed that the novel monomer and polymers have thermoresponsive properties with cloud point in the range between 10 and 90 °C. The cloud point was increased by 56.2 °C when the polymer molecular weight increased from 0.47 × 10⁴ g mol^?1 to 3.69 × 10⁴ g mol^?1. In addition, the cloud point of PHIPPVTA was decreased by 18.8 °C with the increase of polymer concentration from 5 to 10 mg mL^?1. A slight increase (0.1–3.5 °C) of cloud point has been observed after knocking off the end‐groups of PHIPPVTA. Moreover, the cloud point of polymer increased with increasing of its molecular weight with or without the trithiocarbonate end‐groups, which showed the opposite trend comparing with other thermoresponsive polymers with flexible backbones. These polymers show a dramatic solvent isotopic effect that the cloud point in D₂O was lower than in H₂O. © 2012 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2012     

Poly(thienylene‐vinylene‐thienylene) with cyano substituent: Synthesis and application in field‐effect transistor and polymer solar cell

A novel conjugated polymer, poly(thienylene‐vinylene‐thienylene) with cyano substituent ( CN‐PTVT ) was synthesized via Stille coupling for the application in air stable field‐effect transistor and polymer solar cell. The polymer was characterized by ¹H NMR, elemental analysis, UV‐vis absorption and photoluminescence spectroscopy, TGA, cyclic voltammetry and XRD analysis. CN‐PTVT exhibits a good thermal stability with 5% weight loss at 306 °C. The FET hole mobility of the polymer reached 5.9 × 10^?3 cm² V^?1 s^?1 with I_on/I_off ratio of 4.9 × 10⁴, which is one of the highest performance among the air‐stable amorphous polymers. The polymer solar cell based on CN‐PTVT as donor and PCBM as acceptor shows a relatively high open‐circuit voltage of 0.82 V and a power conversion efficiency of 0.3% under the illumination of AM1.5, 100 mW/cm². © 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 47: 4028–4036, 2009     

Thermal oxidation of polyacetylene

The thermal oxidation of undoped trans-polyacetylene powder in dry air has been studied and the principal features of the mechanism have been developed. Thermogravimetric and differential thermal analysis reveal an exothermic process that first leads to a weight increase, followed by precipitous weight loss above 240°C due to formation of volatile oxidation products. Isothermal weight gain studies between 25 and 142°C show first-order kinetics below 90°C with a rate constant of 3.10^?7 s^?1 at 25°C and an apparent activation energy of 16 kcal/mol. A weight gain of more than 40% has been observed at 25°C after 2000 h of exposure to air. A change in first-order kinetics occurs at temperatures above 90°C. Identification of solid oxidation products with photoacoustic infrared spectroscopy reveals that oxygen intercalates into the polymer structure in large concentrations, similar to other electron acceptors. However, oxidative attack on the polymer backbone occurs simultaneously. At elevated temperatures or for long-term oxygen exposure, the concentration of dopant oxygen decreases, probably by intramolecular regrouping of hydrogen atoms, resulting in the formation of hydroxyl groups and enhanced polymer degradation. This mechanism is consistent with the finding of others that the conductivity of polyacetylene upon oxygen exposure increases initially before decreasing significantly with continued exposure, especially at elevated temperatures.     

Polyether azomethines. I. Synthesis and characterization

Six new polyether azomethines were synthesized by melt and solution polycondensation of six different diamines with 4,4′-[1,4-phenylene bis(oxy)] bisbenzaldehyde. The polymers synthesized by solution method are yellow to white in color and had inherent viscosities up to 0.59 dL/g in concentrated H₂SO₄. The polymers obtained by melt condensation show higher viscosity. Except polymer IV , others are insoluble in common organic solvents. The polymers were characterized by IR, x-ray, elemental analysis, and DSC study. The thermal stability of the polymers was evaluated by TGA and IGA study. Polymers I-III are highly thermally and thermooxidatively stable and exhibit no appreciable decomposition up to 420°C both in air and nitrogen atmosphere. It was shown that the curing of the polyazo-methines takes place by opening up of the ? CH?N? linkages at higher temperature. The electrical conductivities of the virgin and iodine doped polymers were as high as 10^?11?10^?16 and 10^?6?10^?8S cm^?1, respectively, at 30°C. Electronic spectra of the undoped polymers ( I-III ) indicated a large bathochromic shift of the ? – ?^* absorptions band (376 nm) due to ? C?N? bonds of the model compound. This can be attributed to extensive delocalization of the electrons along the polymer chain. © 1995 John Wiley & Sons, Inc.     

Synthesis and properties of a soluble and widely conjugated polyacetylene with anthryl pendant

The metathesis polymerization of an anthrylacetylene bearing an alkyl ester group, 9‐(10‐hexoxycarbonyl)anthrylacetylene ( 1 ), was conducted with various transition‐metal catalysts. A completely soluble black polymer was obtained from 1 in a good yield when W‐based catalysts were employed. The polymerization at a high monomer concentration (1 M) and a high temperature (80 °C) led to the formation of poly( 1 ) with a weight‐average molecular weight of 297 × 10³ in an 80% yield. The use of cocatalysts unexpectedly decreased both the yield and molecular weight of poly( 1 ). Rh‐catalyzed and Mo‐catalyzed polymerizations, however, resulted in poor yields of the polymer. The ultraviolet–visible spectrum of poly( 1 ) showed a significantly redshifted absorption (λ_max = 571) with a cutoff at 780 nm, which verified the very high order of conjugation of the main chain. Poly( 1 ) exhibited the largest third‐order nonlinear optical susceptibility [χ⁽³⁾ (−ω; ω, 0, 0) = − 1.9 × 10⁻¹⁰ esu] among the polymers from the monosubstituted polyacetylenes synthesized so far. The electrical conductivity of poly( 1 ) in an I₂‐doped state was 8.77 × 10⁻⁴ at 293 K. © 2000 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 38: 4717–4723, 2000     

Synthesis and properties of poly (diphenylacetylenes) having aliphatic para-substituents

1-(p-t-Butylphenyl)-2-phenylacetylene and 1-(p-n-butylphenyl)-2-phenylacetylene were polymerized in catalytic systems based on TaCl₅ to give new polymers in high yields. These monomers were more reactive than diphenylacetylene (DPA) in copolymerization. Unlike poly (DPA), the present polymers were soluble in toluene, CHCl₃, etc. owing to the high configurational entropy induced by the para-substituents. Their relative weight-average molecular weights determined by GPC were in the range of 6 × 10⁵–36 × 10⁵, and films could be obtained by solution casting. These polymers were fairly thermally stable, as seen from their high onset temperatures (320–380°C) of weight loss in TGA in air. The oxygen permeability coefficient of the polymer with t-Bu group was 1100 barrers, the highest among those of all the hydrocarbon polymers. © 1994 John Wiley & Sons, Inc.     

Polymerization of 1-chloro-2-β-naphthylacetylene by Mo catalysts and polymer properties

1-Chloro-2-β-naphthylacetylene (ClβNA) polymerized in good yields in the presence of MoCl₅-based catalysts. The highest weight-average molecular weight of poly(ClβNA) reached about 3 × 10⁵. The polymer was a yellow solid (absorption cutoff in CHCl₃ 450 nm). It was soluble in toluene, chloroform, etc., and provided a tough film by the solvent casting method. The polymer retained its weight up to 300°C in air; it was thermally less stable than poly(1-chloro-2-phenylacetylene) but more stable than poly(β-naphthylacetylene). The oxygen permeability coefficient (P_O2) of this polymer was 19 barrers (25°C), which is fairly small for a substituted polyacetylene. © 1996 John Wiley & Sons, Inc.     

LINEAR AND HYPERBRANCHED POLYMERS WITH HIGH THERMAL STABILITY AND LUMINESCENCE EFFICIENCY

New acetylene monomers, 6-{[(1-naphthylethynyl-4-phenyl)carbonyl]oxy}-1-pheny-1-hexyne (1), 2, 5-diethynyl-thiophene (3), and 4,4'-diethynylbiphenyl(6) were synthesized. Homopolymerization of 1 and copolycyclotrimerizations of 3and 6 with 1-heptyne and 1-octyne have been achieved with WCl_6- and TaCl_5-Ph_4Sn catalysts, respectively, giving solublelinear disubstituted polyacetylene (2) and hyperbranched polyarylenes (5 and 8) with high molecular weights (up to 1.2×10~5) in high yields (up to 98%). The trictures and properties of the polymers are characterized and evaluated by IR, NMR,TGA, UV, photoluminescence (PL), and electroluminescence (EL) analyses. All the polymers possess high thermal stabilityand emit strong blue ligh upon photoexcitation. The intensity of the emitted light is greater than that of poly(1-phenyl-1-octyne), a well-known highly luminescent disubstituted polyacetylene. Little aggregation-induced red shift in the PL wasobserved in the thin films of the polymers. By constructing a multi-layer EL device, high EL quantum yield (0.18%) has beenachieved in 2, which are the best results for substituted polyacetylenes attainable so far.     

Molecular weight distribution and thermal characterization of polydimethylsilmethylene

1,1,3,3-Tetramethyl-1,3-disilacyclobutane (I) was polymerized under the following conditions with H₂PtCl₆·6H₂O as catalyst: (a) addition of I dropwise to a large excess of catalyst at room temperature, producing [(CH₃)₃SiCH₂(CH₃)₂Si]₂O in 90% yield; (b) polymerization at room temperature in the presence of 10% water with 23 ppm Pt, yielding 9% conversion to low molecular weight polymer after 4 weeks; (c) polymerization in an open vessel (25°C., 7 ppm Pt, M?_n = 1.2 × 10⁵), a closed vessel (100°C., 28 ppm Pt, M?_n = 1.7 × 10⁵), in a closed tube after twice freezing and evacuating (25°C., 23 ppm Pt, M?_n = 2.9 × 10⁵); (d) polymerization in an oxygen atmosphere (25°C., 17 ppm Pt, M?_n = 2.7 × 10⁵). The molecular weight distributions of the polymers with M?_n = 1.2 × 10⁵ and 1.7 × 10⁵ was studied by gel-permeation chromatography. Ratios of M?_w/M?_n are 3.1 and 2.7, respectively. In both cases a long tail of high molecular weight polymer is evident. Interpretation of the molecular weight distributions is qualitatively discussed on the basis of a postulated seven-step mechanism. Water is shown to be a source of chain termination. Evidence is presented for the existance of ?SiOSi? and ?SiOH in the silmethylene polymers. Negligible cyclization occurs. Orders of thermal stability measured by DTA and TGA for polydimethylsilmethylene (A), polydimethylsiloxane (B), and polysiobutylene (C) are: in He, A > B > C; in air, in air, B > C ? A. A fractionally precipitated polydimethylsilmethylene had a weight loss of less than 5% by 600°C. by TGA analysis at 10°C./min. in He.     

Thermal decomposition of poly(α,α,α′,α′-tetrafluoro-p-xylylene) in nitrogen and oxygen

The thermal decomposition of poly(α,α,α′,α′-tetrafluoro-p-xylylene) (parylene AF-4) films with thicknesses of ca. 7.5 and 10 μm has been studied by both dynamic (10°C min^?1) and isothermal TG in either nitrogen or oxygen atmospheres. In dynamic studies with nitrogen, gross decomposition occurs between 546.7±1.4 and 589.0±2.6°C, with 26.8±4.4% of the initial mass remaining at 700°C. With oxygen as the purge gas, the onset of decomposition shifts slightly to 530.8±4.2°C. The end of the transition at 587.4±2.6°C is within experimental error of the nitrogen value, but no polymer remains above 600°C. Isothermal data were obtained at 10°C intervals from 420 to 490°C in nitrogen, and from 390 to 450°C in oxygen. Plots of log(Δ%wt/Δt)vs. T^?1 are linear throughout the specified range for oxygen and from 420 to 470°C for nitrogen. The calculated activation energies of (147±16) kJ mol^?1 and (150±12) kJ mol^?1 in N₂ and O₂, respectively, are equal within experimental error.     

Polybenzimidazoles tethered with N‐phenyl 1,2,4‐triazole units as polymer electrolytes for fuel cells

Polybenzimidazole (PBI) polymers tethered with N‐phenyl 1,2,4‐triazole (NPT) groups were prepared from a newly synthesized aromatic diacid, 3′‐(4‐phenyl‐4H‐1,2,4‐triazole‐3,5‐diyl) dibenzoic acid (PTDBA). The obtained polymers show superior thermal and chemical stability and good solubility in many aprotic solvents. The inherent viscosities of all polymers were around 1 dL/g. They exhibit high thermal stability with initial decomposition temperature ranging from 515 to 530 °C, high glass transition temperature ranging from 375 to 410 °C, and good mechanical properties with tensile stress in the range of 66–98 MPa and modulus 1897–2600 MPa. XRD analysis indicates that these polymers are amorphous in nature. Physicochemical properties such as water and phosphoric acid‐uptake, oxidative stability, and proton conductivity of membranes of these polymers have also been determined. The proton conductivity ranged from 4.7 × 10^?3 to 1.8 × 10^?2 S cm^?1 at 175 °C in dry conditions. © 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 47: 2289–2303, 2009     

Synthesis,light emission,and photovoltaic properties of perylene‐containing polyacetylenes

Perylene (Py)‐containing polyacetylenes with different skeleton structures ? [HC?C(C₆H₄)CO₂? Py]_n? (P 1 ), ? [HC?C(CH₂)₈CO₂? Py]_n? (P 2 ), and ? {[(C₆H₅) C?C(CH₂)₉NH₂]? co? [(C₆H₅)C?C(CH₂)₉? Py]}_n? (P 3 ) are synthesized in satisfactory yields by Rh‐catalyzed polymerization (for P 1 and P 2 ) and polymer reaction (for P 3 ). All the polymers are soluble and possess high molecular weights (M_w up to 2.8 × 10⁵). Their structures and properties are characterized and evaluated by IR, NMR, UV, TGA, PL, and photovoltaic (PV) analyses. The polymers are thermally stable, losing little of their weights when heated to 330 °C. When their solutions are irradiated, their perylene pendants emit intense red fluorescence at 610 nm. PV cells with a configuration of ITO/PEDOT:PSS/polymer/LiF/Al are fabricated, which show maximum current density of 10.3 μA/cm². The external quantum efficiency is sensitive to the polymer structure, with P 3 exhibiting the highest value of 0.23%. © 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 2025–2037, 2008     

Preparation and properties of oxadiazole‐containing polyacetylenes as electron transport materials

A series of functional polyacetylenes (PAs) bearing diphenyl oxadiazole pendant groups ( P1 – P4 ) were prepared, and the resultant polymers are completely soluble in common organic solvents. Their structures and properties were characterized and evaluated by DSC, TGA, UV, PL, CV, and EL analyses. The results show that all the resulting polymers possesses low LUMO energy level and high thermal stability, and the resultant functional polyacetylenes without spacer group between the polyacetylene conjugated main chain and oxadiazole pendant groups ( P1 – P3 ) show lower LUMO energy level (～?3.87 eV) and higher thermal properties (T_g) than that ( P4 ) with a flexible spacer. The resultant polymer ( P2 ) was applied as an ETM in bilayer electroluminescent devices and effectively enhances external quantum efficiency and the brightness of device, and decreases turn‐on voltages of devices. © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 48: 1406–1414, 2010     

Synthesis and crosslinking reaction of polyacetylenes substituted with benzoxazine rings: Thermally highly stable benzoxazine resins

Novel polyacetylenes, poly( 1 ) and poly( 2 ) substituted with benzoxazine rings were synthesized by the polymerization of the corresponding acetylene monomers 1 and 2 using Rh catalysts, [(nbd)RhCl]₂, and (nbd)Rh⁺B^–Ph₄ (nbd = 2,5‐norbornadiene). The polymers were heated at 250 °C under N₂ to obtain the corresponding polybenzoxazine resins, poly( 1 )′ and poly( 2 )′ possessing polyacetylene main chains via the ring‐opening polymerization of the benzoxazine moieties. The polyacetylene backbones were maintained after crosslinking reaction at 250 °C, which were confirmed by Raman spectroscopy. The benzoxazine resins were thermally highly stable as evidenced by differential scanning calorimetry and thermogravimetric analysis. The surface of poly( 1 )′ film became hydrophilic compared to that of poly( 1 ), while the surfaces of poly( 2 ) and poly( 2 )′ films showed almost the same hydrophilicity judging from the water contact angle measurement. Poly( 1 )′ and poly( 2 )′ exhibited refractive indices smaller than those of poly( 1 ) and poly( 2 ). © 2018 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2018 , 56, 1884–1893     

Substituted polyacetylenes

This article reviews the chemistry of substituted polyacetylenes developed by our research group, more specifically, development of polymerization catalyst, synthesis of new polymers, elucidation of their structure, investigation of their properties, and development of their functions. The main features are as follows: a number of catalysts based on group 5, 6, and 9 transition metals (Nb, Ta, Mo, W, and Rh) have been developed, which include living polymerization catalysts. By using these catalysts, many new substituted polyacetylenes have been synthesized, whose molecular weights are very high (M_w = 10⁴?10⁶). Most of the polymers are soluble in many common solvents and stable enough in the air unlike polyacetylene. Some of these polymers exhibit interesting functions including high gas permeability and photoelectronic properties. © 2006 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 45: 165–180, 2007