Polytrifluormethylstyrole,eine polymerklasse mit aussergewöhnlichen optischen eigenschaften

Homopolymers of 2-, 3- and 4-trifluoromethylstyrene, 4-perfluoroisopropylstyrene, 3,5-bis-trifluoromethyl-styrene and a 1 : 1 copolymer of 2,4- and 2,5-bis-trifluoromethyl-styrene have been synthesized and the refractive indices n_D, Abbe-numbers ν_D and glass transition temperatures of the polymers have been determined. With regard to optical applications poly-2-trifluoromethyl-styrene is particularly interesting since its optical properties are in a region of the n-ν-diagram that has not been reached by thermoplastic polymers or inorganic glasses before. The most important mechanical and thermal properties of this polymer are reported. Reactivity ratios of the binary copolymerisation of 2-trifluoromethyl-styrene with styrene, methyl-methacrylate and n-butyl-acrylate are listed as well as optical data and glass transition temperatures of some copolymers of 2-trifluoromethyl-styrene.     

Synthesis of substituted poly (arylene vinylene) films by vapor deposition polymerization

Summary An efficient method for the synthesis of PPV based polymers, poly ( 2,5-dimethyl-1,4-phenylene vinylene) (DMe-PPV) and poly (2,5-dimethoxy-1,4-phenylene vinylene) (DOMe-PPV) were developed using 2,5-dimethyl-1,4-bis ( chloromethyl ) benzene and 2,5-dimethoxy 1,4-bis ( chloromethyl ) benzene via vapor phase pyrolysis and followed by vapor deposition polymerization. The structure of polymer films were confirmed by FT-IR, solid state NMR and elemental analysis. Thermal gravimetry analysis reveals that the precursor polymer films form a conjugated polymer after thermal conversion at 250°C. The optical and electrical properties of the polymer films were investigated by UV-Vis absorption and photoluminescence spectroscopies. Electroluminescent devices were fabricated using these polymers. Received: 18 May 2000/Revised version: 21 July 2000/Accepted: 28 July 2000     

Relationship between degree of polymerization and optical and thermal properties of fluorene in polycarbonate polymers

The influences of average degree of polymerization (D_p) and terminal group on thermal and optical properties of high refractive indexed transparent polymers were investigated. In this study, 9,9‐bis[4–(2‐hydroxyethoxy) phenyl] fluorene (BPEF) homo polymer was selected because it has been used as a representative monomer in high refractive index polymers as well as its unique property. BPEF has stable amorphous phase and reacts like a polymer. Its unique reaction allows continuous investigation from monomer to polymer. For hydroxyl‐terminated polymer, the refractive index (n_d) decreased with increasing D_p. On the other hand, for a phenolic‐terminated group, n_d increased with increasing D_p, and both converged to same value in high D_p region. As for glass transition temperatures (T_g), both terminal group series were increased as D_p increased. Though T_g of hydroxyl‐terminated polymer was higher than that of phenolic‐terminated polymer in the low D_p region, both converged to the same value and the inverse number of T_g had linear correlation against the weight percentage of carbonyl groups (CO), which was calculated by D_p. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017 , 134, 45042.     

Synthesis of polymers having arylene-vinylene units by palladium-catalyzed hydroarylation polymerization of diethynylbenzene derivatives

Summary Arylene-vinylene-containing polymers with fully aromatic backbone structures were prepared by the palladium-catalyzed hydroarylation polymerization of diethynylbenzene derivatives with diiodobenzene and alkylmalonate anions as a hydride source. For instance, the polymerization of 1,4-bis(4'-dodecyloxy)phenylethynylenebenzene, diiodobenzene, and sodium diethyl benzylmalonate was carried out at 80°C for 2 days in 1,4-dioxane in the presence of Pd(OAc)₂ / tri-o-tolylphosphine (7 equiv. to Pd) to produce a polymer (M _n= 6,390, M _w/M _n= 1.53) in high yield (86 %). Using various diethynylbenzene derivatives, polymers having arylene-vinylene units were also obtained in high yields. Received: 16 December 1999/Accepted: 20 January 2000     

Synthesis and characterization of naphthalene diimide/diethynylbenzene copolymers

A series of conjugated polymers has been synthesized by Sonogashira coupling of N,N′-bis(2-octyldodecyl)-2,6-dibromonaphthalene-1,4,5,8-bis(dicarboximide) and four para-diethynylbenzene derivatives: 1,4-diethynyl-2,5-dihexadecyloxybenzene, 1,4-diethynyl-2,5-bis(2-octyldodecyloxy) benzene, 1,4-bis(2-ethylhexyl)-2,5-diethynylbenzene, 1,4-diethynyl-2,5-bis(trifluoromethyl)benzene. The polymers display absorption maxima at wavelengths ranging from 530 nm to 654 nm with molar absorptivities ranging from ca. 4 to 7 × 10⁴ M^?1 cm^?1. The peak reduction potentials, determined by differential pulse voltammetry, for polymer films varied from ?0.93 to ?1.14 V vs. ferrocenium/ferrocene with the trifluoromethyl-substituted derivative being the most readily reduced. All four polymers exhibited electron transport characteristics in bottom-gate/top-contact field-effect transistors, showing average electron mobility values ranging from 1.4 × 10^?4 to 3.7 × 10^?3 cm² V^?1 s^?1.     

Low relative dielectric permittivities of polyimides and copolyimides derived from non-coplanar diamines and 4,4′-(hexafluoroisopropyl)diphthalic anhydride

Abstract

Two series of polyimides and copolyimdes were solution cast into transparent, flexible and tough films. The glass transition temperatures T _g obtained from dynamic mechanical analysis were moderate compared with commercial polyimides such as Dupont Vespel®. The T _gs for the majority of polymers derived from monomer 1 (2′,5′-bis(p-aminophenoxy)-[1,1′;4′,1≥]terphenyl) (1A-F) were higher than those of polymers derived from monomer 2 (2,5-bis(p-aminophenoxy)biphenyl) (2A-F). The thermal expansion coefficients of the two series of polymers were moderate and comparable. The maximum elongations and moduli of polymers 2A-F were larger than those of polymers 1A-F possibly because polymers 2A-F were more flexible than polymers 1A-F. The relative dielectric permittivities of both series of polymers were measured and exhibited a low value from 2 49 to 3 01 at 100 kHz. In contrast, the relative permittivities calculated using the Clausius-Mosotti relationship were higher. Incorporation of non-coplanar diamines into the polymer chain causes an increase in free volume, which may account for the decrease in relative permittivities.     

Synthesis,spectroscopy, and electrochemical investigation of new conjugated polymers containing thiophene and 1,3,4-thiadiazole in the main chain

Novel photoluminescent donor–acceptor poly(p-phenylenevinylene)-type conjugated polymers containing thiophene and 1,3,4-thiadiazole units in the main chain were synthesized from 2,5-bis(5-bromomethyl-2-thienyl)-1,3,4-thiadiazole and 1,3/1,4-benzenedialdehyde by Wittig–Horner reaction. The synthesized polymers were characterized by the use of thermal analysis and spectroscopic (infrared, UV-visible absorption, and photoluminescence) measurement. The resultant material exhibited bluish green, green, and orange fluorescence in their solution and thin film and solid forms, respectively. The redox property of the polymers has also been studied by cyclic voltammetry. The optical and electrochemical studies reveal that these novel polymers are new promising materials for the development of efficient polymer light-emitting diodes. © 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012     

Influence of melt stability on the crystallization of bis(4-aminophenoxy)benzene-oxydiphthalic anhydride based polyimides

Novel high performance semicrystalline polyimides, based on controlled molecular weight phthalic anhydride (PA) endcapped 1,4-bis(4-aminophenoxy)benzene (TPEQ diamine) and oxydiphthalic dianhydride (ODPA), were synthesized. They exhibited excellent thermal stability in nitrogen and air atmospheres as determined by thermogravimetric analysis (TGA). The glass transition temperatures (T_g) for these polymers ranged from 225°C for the 10,000 M_n (10K) polymer, to 238°C for the 30,000 (30K) M_n material. The observed melting temperatures for all the polymers were ∼420°C. The crystallization behavior of these polymers showed a strong molecular weight dependence, as illustrated by the observation that the 10K and 12.5K polymers crystallized with relative ease, whereas the 15K, 20K, and 30K polymers showed little or no ability to undergo thermal recrystallization. The thermal stability of these polymers above T_m was investigated by studying the effect of time and temperature in the melt on the cold crystallization and melting of these polymers. Increased time and temperature in the melt resulted in lower crystallinity because of melt state degradation, such as crosslinking and branching, as evidenced by an increase in melt viscosity, which was more prominent for the higher molecular weight polymers.     

Synthesis and characterization of highly fluorescent phenylene vinylene containing perfluorocyclobutyl (PFCB) aromatic ether polymers

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%.     

Synthesis and characterization of polymers derived from selenophene

The synthesis of poly(2,5‐selenophen‐oxo‐1,4‐phenylen‐selenide‐1,4‐phenylene‐oxo) (I) and poly(2,5‐selenophen‐oxo‐1,4‐phenylen‐diselenide‐1,4‐phenylen‐oxo) (II) by reaction of 2,5‐bis(1,4‐bromo‐phenylen‐oxo‐)‐selenophene with sodium selenide or diselenide, respectively, using dimethylformamide as solvent, is described. Both monomers and polymers were characterized by elemental analysis, melting point, and FTIR spectroscopy. Polymers I and II were doped with iodine and SbF₅ and characterized by SEM and XPS. Also, the conductivity and the T_g values were determined. For both polymers the best doping agent was iodine, although polymer II always presented higher conductivity, reaching values of about 6 · 10^?9 S · cm^?1. The T_g values suggest a likely crosslinking of the chains in polymer II when doped with SbF₅. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 81: 2019–2026, 2001     

Synthesis, characterization and photovoltaic properties of random poly(arylene-vinylene)s containing benzothiadiazole

New random poly(arylene-vinylene)s obtained by combining different amounts of benzo[2,1,3]thiadiazole units with 9,9-dialkylfluorene and/or 1,4-dialkoxybenzene building blocks were synthesized by the Suzuki-Heck polymerization and characterized for use in bulk hetero-junction solar cells. Their optical, electrochemical, morphological and photovoltaic features were investigated. Notwithstanding the relatively low weight-average molecular weights of the obtained polymers (7000-13000 Da), they formed good quality films by spin-coating. UV-Vis measurements permitted the evaluation of their band gap (1.77-2.12 eV), enabling them to harvest a broad portion of the solar spectrum from 350 nm to 650-700 nm. An electrochemical study revealed that the copolymers are endowed with HOMO/LUMO energy levels suitable for both an efficient electron transfer and a high open circuit voltage (V_oc) for devices embodying the polymer/PCBM blends. This investigation pinpoints the important role of the copolymer composition (in terms of molar ratio of the monomeric units) on the performance of the donors in BHJs. In fact, in disagreement with the presumed V_oc and current densities, the terpolymer poly[1,4-bis(2-ethylhexyloxy)-2,5-phenylene-vinylene-co-9,9-bis(2-ethylhexyl)-2,7-fluorenylene-vinylene-co-4,7-benzo[2,1,3]thiadiazolylene-vinylene] showed the best performance of the copolymer series, with a PCE of 0.4% and a V_oc of 0.76 V, probably due to the favorable phase separation in the blend and consequently a better exciton dissociation.     

Synthesis,characterization, and optoelectronic properties of two new polyfluorenes/poly(p‐phenylenevinylene)s copolymers

Two novel copolymers of polyfluorenes/poly(p‐phenylenevinylene)s copolymers with p‐tert‐butyl‐phenylenemethylene groups in the C‐9 position of alternating fluorene unit, poly[1,4‐(2,5‐dibutyloxyl)‐phenyleneviny lene‐alt‐9‐(p‐tert‐butyl‐phenylenemethylene)fluorene] and poly[1,4‐(2,5‐dioctyloxyl)‐phenylenevinylene‐alt‐9‐(p‐tert‐butyl‐phenylenemethylene)fluorine], have been synthesized via the Heck polycondensation reaction. The synthesized polymers were characterized by FTIR, NMR, DSC, TGA, UV–vis, and PL spectra. The polymers showed high glass transition temperatures and good thermal stability. A polymer light‐emitting diode with the configuration ITO/PEDOT:PSS/P2/Ca/Al has been fabricated. The device emitted a yellow light with a peak wavelength of 578 nm similar to the PL spectra of the copolymer film. A maximal luminance of 534 cd/m² was obtained at a driving voltage of 24.5 V. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 3955–3962, 2006     

Synthesis and Characterization of Novel AB and ABA Rod–Coil Block Copolymers

Two series of novel rod–coil block copolymers, poly(ɛ-caprolactone)-b-poly{2,5-bis[(4-methoxyphenyl) oxycarbonyl] styrene} (PCL-b-PMPCS) and poly{2,5-bis[(4-methoxyphenyl) oxycarbonyl] styrene}-b-poly(ɛ-caprolactone)-b-poly{2,5-bis[(4-methoxyphenyl) oxycarbonyl] styrene} (PMPCS-b-PCL-b-PMPCS), were successfully synthesized via atom transfer radical polymerization in chlorobenzene solution using macro-initiator and CuBr/Sparteine complex as catalyst. The results show that the number average molecular weight M_n increased versus the monomer conversion and that the polydispersity M_w/M_n was quite narrow (<1.35), which were the character of controlled polymerization. The structure of the block copolymers was experimentally confirmed by ¹H NMR. And the liquid crystalline behavior of them was studied using DSC and POM. The data obtained implied that the block copolymers with low molar percentage of PMPCS block could show T_m of PCL. While only the copolymers with long rigid segment PMPCS could form liquid crystalline phase, which was quite stable with a high clearing point.     

Chain structure,phase morphology,and toughness relationships in polymers and blends

We present chain structure, phase morphology, and toughness relationships in thermoplastic polymers and polymer/rubber blends. In neat polymers, molecular aspects of craze/yield behavior are controlled by two chain parameters: entanglement density ν_e and characteristic ratio C_∞. The crazing stress is proportional to ν, and the yield stress is proportional to C_∞. The dispersed rubber toughens a polymer/rubber blend mainly by promoting energy dissipation of the matrix. The toughening efficiency correlates with the rubber phase morphology and the chain structure of the matrix.     

π-Conjugated polyphenylene gels with charge transfer structures assisted by TCNQ

The reaction of π-conjugated poly(p-phenylene)s (PPPs) consisting of 2- or 3-amino-1,4-phenylene (NH₂Ph) and 2,5-dioctyloxy-1,4-phenylene (OctPh) or 9,9-dihexylfluorene-2,7-diyl (HexFlu) rings [polymer-1: (NH₂Ph-OctPh)_n and polymer-2: (NH₂Ph-HexFlu)_n] with 7,7,8,8-tetracyanoquinodimethane (TCNQ) yielded gel-1 and gel-2. These gels were form through a charge transfer (CT) between the NH₂ group and TCNQ, causing the gels to be linked by a TCNQ dianion. ESR measurements suggest that radical species generated by CT in the gels are delocalized in the π-conjugated polymer backbone. UV–vis measurements revealed that CT between the NH₂ group and TCNQ was essential for gel formation. When a dimethyl sulfoxide (DMSO)/TCNQ solution was added to a chloroform solution of the polymers, the absorption corresponding to CT bands increased with an increasing amount of TCNQ. Photoluminescence (PL) measurements suggested that TCNQ served as a quencher for fluorescent polymer-1 and polymer-2. Quenching behavior was investigated by Stern–Volmer analysis.     

Synthesis and electrical conductivity of AsF5-doped poly(arylene vinylenes)

Summary A series of polymers containing 2,5-disubstituted phenylene vinylene units, and the polymer containing 1,4-naphthalene vinylene units, were prepared by polymerization of their bis(sulfonium salts) through a base elimination reaction in solution. Films of these polymers were cast from aqueous solution and chemically treated (doped) with AsF₅ vapor. The electrically conductivities of the doped films varied greatly with changes in polymer structure, with the highest value obtained of 1.8 ohm^–1 cm^–1 for poly (2,5-dimethoxyphenylene vinylene).     

Imidazole-Containing Ligands Assisted Self Assembly of Two New Cd(II) Coordination Polymers: Syntheses, Crystal Structures and Photoluminescent Properties

Two new coordination polymers, {[Cd₂(PDC)₂(H₂O)₂(L₁)]·2H₂O}_n (1) and {[Cd (2,5-PDC)(H₂O)(L₂)]·H₂O}_n (2), have been obtained from hydrothermal reactions of Cd²⁺ ion with the 2,5-pyridinedicarboxylic acid (H₂PDC) and two imidazole-containing ligands [L₁ = 1,4-bis(imidazol-1-yl)benzene and L₂ = 1,4-bis(1-imidazol-yl)-2,5-dimethylbenzene]. Complex 1 features a three-dimensional 6-connected rob topological net. Complex 2 shows a two-dimensional 6-connected hxl topological net. The structural differences between 1 and 2 demonstrate that the different imidazole-containing ligands play critical roles in the formation of the resulting frameworks. The photoluminescent properties of 1 and 2 have also been investigated.     

New soluble π-conjugated polymers containing 2-diisopropylamino-1,3,5-triazine unit: synthesis,characterization and optical properties

A new type of π-conjugated polymers containing 2-diisopropylamino-1,3,5-triazine were prepared via Sonogashira or Suzuki coupling reaction. The structures of the polymers were performed by FT-IR, ¹H-NMR, UV–vis spectroscopy, photoluminescence spectroscopy, gel permeation chromatography, thermal analysis and X-ray diffraction analysis. These derived polymers were soluble in common organic solvents such as tetrahydrofuran, chloroform, toluene, and showed good thermal stability. Polymers containing 1,4-diethynyl-2,5-bis(dialkoxy)benzene unit in polymer main chain emitted blue-green light in solution phase under UV light irradiation except with polymer containing 9,9-dioctylfluorene(blue light). Acidochromic behaviors of polymers were studied in CHCl₃-CF₃COOH mixtures. 9,9-Dioctylfluorene-containing polymer displayed better acidochromic property and linear relationship between absorbance and concentration with the concentration of CF₃COOH from 5.384?×?10^?4 to 26.92?×?10^?4 mol/L. Electrochemical behaviors of polymers depicted p-doping and some hole-transporting properties. XRD results showed that polymers exhibited certain crystallinity.     

Phase relationships of rigid rod polymer/flexible coil polymer/solvent ternary systems

Phase diagrams of two types of rigid rod polymer/flexible coil polymer/methanesulfonic acid (MSA) ternary systems were determined by polarized optical microscopy at ambient conditions. The rigid rod polymer is a wholly aromatic high temperature resistant (no measurable T_g) poly (p-phenylenebenzobisthiazole) (PPBT). One of the flexible coil polymers is a wholly aromatic high temperature resistant poly (2,5′(6′) benzimidazole) (ABPBI), the other is a thermoplastic poly[2,2′ -(1–4-phenylene)-6,6′ -bis (3-phenyl-quinoxaline)] (PPQ) with T_g of 359°C. The solvent is methane-sulfonic acid (MSA). The experimentally determined critical concentration points, C_cr, are in excellent agreement with Flory's recent theory. Total phase segregation between the polymer pair in ternary solution was predicted and observed at C > C_cr. Different decomposition mechanisms of phase separation were observed as a function of concentration.     

Copolyesters developed from bio-based 2,5-furandicarboxylic acid: Synthesis,sequence distribution,mechanical, and barrier properties of poly(propylene-co-1,4-cyclohexanedimethylene 2,5-furandicarboxylate)s

A series of poly(propylene-co-1,4-cyclohexanedimethylene 2,5-furandicarboxylate)s (PPCFs) with different compositions were synthesized from bio-based aromatic monomer 2,5-furandicarboxylic acid and 1,3-propanediol (PDO), along with 1,4-cyclohexanedimethylene (CHDM). The chemical structure, composition, and sequence distribution of PPCFs were determined by nuclear magnetic resonance (¹H NMR and ¹³C NMR). Results showed that the compositions of copolyesters depended on the feed molar ratio of PDO and CHDM, and all the obtained PPCFs copolyesters had triad component in a random sequential structure. With the addition of CHDM, the gas barrier properties of poly(propylene 2,5-furandicarboxylate) (PPF) deteriorated. However, when the content of CHDM reached 79%, PPCF79 still showed the CO₂ and O₂ barrier improvement factor of 4.5 and 3.25, respectively, which were better than those of poly(ethylene naphthalate), a well-known polymer with barrier property. Besides, PPCF79 showed good performance on tensile modulus, tensile strength, elongation at break, and the crystallization enthalpy was improved from 3.2 J g⁻¹ for PPF to 30.7 J g⁻¹ for PPCF79. It has the potential to serve as a promising bio-based polymer with excellent comprehensive performance. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019 , 136, 47291.