High‐thermally stable and high‐bandwidth graded index plastic optical fiber for vehicle networks

Radial refractive index profiles within the graded index plastic optical fiber (GI‐POF) is formed by adding a dopant to a polymer. This addition of the dopant significantly decreased the T_g of the polymer due to the plasticization. This disadvantage made the installation of the GI‐POF difficult, especially in vehicle networks in which high thermal stability is required. We have suggested 9‐bromophenanthrene (BPT) as a novel dopant induced less plasticization for poly(methyl methacrylate) (PMMA) than the conventional dopants. However, although the fabricated GI‐POF using BPT had high enough thermal stability for vehicle networks, the attenuation was 800 dB/km and it could not be used. This high attenuation was caused by contaminant in the fabrication process of fibers. In this study, we succeeded to fabricate a GI‐POF with low‐attenuation and high‐thermal stability using highly pure BPT. Its attenuation was improved to 240 dB/km at 650 nm, which was enough transparency for vehicle networks. The T_g of the GIPOF was improved to 107 °C from 90 °C. The thermal stability of the GI‐POF below 85 °C/dry and 75 °C/85%RH was demonstrated to be as high as that of the commercially available step index POF. The bandwidth of the GI‐POF could be estimated over 4.0 GHz for the 50‐m fiber. These results demonstrated that our GI‐POF should qualify to be used in vehicle network. © 2011 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 49: 1464–1469, 2011     

梯度折射率塑料光纤的研究进展

论述了梯度折射率塑料光纤的研究背景。并对当前梯度折射率塑料光纤的制备方法,梯度折率塑料光纤的折射率梯度的形成机理的研究,及功能梯度折射率塑料光纤的研究状况进行综述。同时展望了梯度折射塑料光纤的发展趋势。     

Photoluminescent,liquid‐crystalline,and electrochemical properties of para‐phenylene‐based alternating conjugated copolymers

Novel liquid‐crystalline alternating conjugated copolymers [ P(P(6)CN‐alt‐Cz) and P(P(6)CN‐alt‐MeP) ] with phenylene and carbazolylene or phenylene with methyl substitution onto the main chain have been synthesized through palladium‐catalyzed Suzuki coupling reactions. The influence of the incorporation of carbazolylene and the substituted phenylene into the main chain on the thermal, mesomorphic, and luminescent properties has been investigated by Fourier transform infrared spectroscopy, thermogravimetry, differential scanning calorimetry, polarized optical microscopy, ultraviolet–visible spectroscopy, photoluminescence (PL), and cyclic voltammetry. These polymers show highly thermal stability, losing little of their weights when heated to 360 °C. The conjugated copolymers exhibit liquid crystallinity at elevated temperature. The existence of the chromophoric terphenyl core endows the copolymers with high PL and the polymer P(P(6)CN‐alt‐Cz containing carbazolylene unit can emit more pure blue light. All the copolymer films with low band gaps about 2.3–2.4 eV undergo reversible oxidation and reduction processes, significantly lower than the band gap of poly(p‐phenylene). © 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 48: 434–442, 2010     

Correction of Refractive-Index Distribution Model in Graded-Index Polymer Optical Fiber Rod

The theoretical and experimental validation was made to Lorenz function model of refractive index distribution in graded index polymer optical fiber (GI POF) by experimental data. It was found that simulating error is great when molecule bulk ratio is larger than one. According to calculating results, exponent parameter of the molecule bulk ratio in the model was corrected to 1.1, so the simulating error was remarkably reduced from ≤65% to <20%. It showed that influence of the molecule bulk ratio on refractive index distribution in GI POF is great.     

Stimulated emission and ultrafast optical switching in a ter(9,9′‐spirobifluorene)‐co‐methylmethacrylate copolymer

A methacrylate‐functionalized 9,9′‐spirobifluorene trimer is copolymerized with methylmethacrylate (MMA). The photophysical characterization of this copolymer using pump‐probe studies, in solution, as films and in plastic optical fibers (POFs) demonstrates that it shows interesting photonic properties for data communication such as high‐stimulated emission cross section (σ_SE = 2.5 × 10^?16 cm²), good thermal, and optical stability, the ability to perform all‐optical ultrafast switching, and low attenuation when doped into POFs. In addition, the material shows interesting optically induced conformational control in solution and the studies demonstrate the surprising result that intrachain polaron pairs can be generated even in well‐isolated 3‐unit oligomers. Although the material is not yet soluble enough in MMA to create highly efficient photonic devices and the gain spectrum is not optimized to overlap with the region of low attenuation in polymethylmethacrylate POFs, these studies are a good starting point to further optimize copolymers for incorporation into POF networks. © 2010 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys, 2010     

梯度型聚合物光纤中折射率分布的洛仑兹函数模型应用

利用洛仑兹函数对梯度型聚合物光纤(棒)中折射率分布曲线进行模拟,建立折射率分布的洛仑兹函数模型.该模型只需掺杂物的初始浓度、分子体积和聚合温度3个基本参数.利用该模型对各种高折射率的掺杂物掺杂聚甲基丙烯酸甲酯(PMMA)制备的梯度型聚合物光纤中的折射率分布进行了预测,发现掺杂物的折射率比分子体积对折射率梯度的影响更大;惰性掺杂物中二苯硫(DPS)掺杂效率最高;共聚掺杂物中苯甲酸乙烯酯(VB)掺杂效率最高.     

Status and dreams of photonics polymer for IT

We have proposed a low-loss, high-bandwidth and large-core graded-index plastic optical fiber (GI POF) in data-corn, area. The GI POF enables us to eliminate the “modal noise” problem which is observed in medium-core silica fibers. Therefore, stable high-speed data transmission can be realized by the GI POF rather than medium-core silica fibers. Furthermore, advent of perfluorinated (PF) polymer based GI POF network can support higher transmission than silica fibers network because of the small material dispersion of PF polymer compared with silica. In addition, we proposed a “highly scattering optical transmission (HSOT) polymer” and applied it to a light guide plate of a liquid crystal display backlight. The HSOT polymer backlight that was designed using the HSOT designing simulator demonstrated twice the brightness of the conventional taransparent backlight with sufficient color uniformity. Furthermore, we proposed the two types of zero-birefringence polymers synthesized by the random copolymerization method and the anisotropic molecule dopant method. Both of the polymers exhibited no orientational birefringence for any orientation of polymer chains.     

A novel photobleachable polysilane copolymer for optical waveguide fabrication

Poly(methylphenylsilane)‐poly(benzylmethacrylate) (PMPS‐PBzMA) block copolymer was prepared by photopolymerization of benzylmethacrylate (BzMA) monomer using PMPS as a macromolecular photo‐radical initiator. Its application as a photobleachable polymer material for optical waveguide fabrication was investigated. By changing weight ratios of BzMA to PMPS during polymerization, the obtained PMPS‐PBzMA showed different photo‐induced refractive changes. PMPS‐PBzMA proved to have good photosensitivity, optical properties, and thermal stability. A multimode PMPS‐PBzMA optical waveguide was achieved, with a propagation loss of 1.0 dB/cm at 1310 nm. Copyright © 2009 John Wiley & Sons, Ltd.     

Resist polymers: Part IX—Thermolysis of chlorine-containing acrylate polymers

The thermal degradation of poly(chloroethyl methacrylate) (PCEMA), poly(trichloroethyl methacrylate) (PTCEMA), poly(methyl-α-chloroacrylate) (PMCA) and their copolymers with methyl methacrylate (MMA) has been investigated. Both ester decomposition and main chain scission occur for the chloroalkyl methacrylate polymers with the former playing the dominant role. In contradistinction, HCl elimination and aromatization prevail over other processes for PMCA. The thermolysis results are compared with radiolysis results.     

Synthesis and properties of copolymers of methyl methacrylate with 2,3,4,5,6‐pentafluoro and 4‐trifluoromethyl 2,3,5,6‐tetrafluoro styrenes: An intrachain interaction between methyl ester and fluoro aromatic moieties

2,3,4,5,6‐Pentafluoro and 4‐trifluoromethyl 2,3,5,6‐tetrafluoro styrenes were readily copolymerized with methyl methacrylate (MMA) by a free radical initiator. The copolymers were soluble in tetrahydrofuran and acetone. The films obtained were transparent and flexible. The glass transition temperatures (T_gs) of the copolymers were found positively deviated from the Gordon–Taylor equation. The positive deviation could be accounted for by dipole–dipole intrachain interaction between the methyl ester group of MMA and the highly fluorinated aromatic moiety, which resulted in a decrease in the segmental mobility of the polymer chains and the enhanced T_g values of the copolymers. The water absorption of PMMA was greatly decreased by copolymerization of MMA with the highly fluorinated styrenes. With as little as 10 mol % of pentafluoro styrene content in the copolymer, the water absorption was decreased to one‐third of that for pure PMMA. The fluorinated styrenes‐MMA copolymers were thermally stable up to 420 °C under air and nitrogen atmospheres. With 50 mol % of MMA in the copolymer, the copolymer was still stable up to 350 °C. Since these copolymers contain a large number of fluorine atoms, the light absorption in the region of the visible to near infrared is decreased in comparison with nonfluorinated polymers. Thus, these copolymers may be suitable for application in optical devices, such as optical fibers and waveguides. © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2010     

Models for adhesion at weak polymer interfaces

The weak interfaces between immiscible polymer pairs typically fail through chain scission. The critical facture toughness for such interfaces is closely related to the density of intermolecular entanglements at the interface. From scaling analysis, a simple correlation between facture toughness and chain entanglement was developed. It predicts well the interfacial adhesion for many immiscible polymer pairs found in the literature. For an interface with block copolymer reinforcement, its critical fracture toughness comes from both intermolecular entanglements of homopolymers and copolymer bridges. In the chain scission regime (low copolymer coverage), the block copolymer contribution is found proportional to copolymer interfacial coverage, with the coefficient being the energy to stretch and break a copolymer chain. The chain‐breaking energy for different copolymers was evaluated and compared to literature data. © 2009 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 47: 2313–2319, 2009     

Aliphatic-aromatic copolycarbonates derived from 2,2,4,4-tetramethyl-1,3-cyclobutanediol

The synthesis of copolycarbonates with high aliphatic contents for possible applications as optical plastics is described. Copolymers of 2,2,4,4-tetramethyl-1,3-cyclobutanediol (TMCBD) with a series of 14 bisphenol derivatives were prepared and characterized. The refractive index of these materials varies from 1.49 for the 2,2-hexafluoropropane substituted copolymer to 1.57 for the 9,9-fluorene substituted copolymer; thus, all of the copolymers exhibit lower refractive indices than the bisphenol A homopolycarbonate. The glass tran-sition temperatures of the copolymers vary from 110 to 210°C; the beta transition tem-peratures vary from -70 to 0°C when measured at 10 Hz by dynamic mechanical analysis. The copolymers exhibited good thermal stability (0–3% weight loss) when heated above the glass transition temperature, and only undergo extensive decomposition (80–90%) at 300–360°C. © 1995 John Wiley & Sons, Inc.     

Synthesis and properties of gradient copolymers based on 2‐phenyl‐2‐oxazoline and 2‐nonyl‐2‐oxazoline

In this study, the structure–property relationships for a series of statistical 2‐nonyl‐2‐oxazoline (NonOx) and 2‐phenyl‐2‐oxazoline (PhOx) copolymers were investigated for the first time. The copolymerization kinetics were studied and the reactivity ratios were calculated to be r_NonOx = 7.1 ± 1.4 and r_PhOx = 0.02 ± 0.1 revealing the formation of gradient copolymers. The synthesis of a systematical series of NonOx–PhOx copolymers is described, whereby the amount of NonOx was increased in steps of 10 mol %. The thermal and surface properties were investigated for this series of well‐defined copolymers. The thermal properties revealed a linear decrease in glass transition temperature for copolymers containing up to 39 wt % NonOx. Furthermore, the melting temperature of the copolymers containing 0 to 55 wt % PhOx linearly decreased most likely due to disturbance of the NonOx crystalline domains by incorporation of PhOx in the NonOx part of the copolymer. The surface energies of spincoated polymer films revealed a strong decrease in surface energy upon incorporation of NonOx in the copolymers due to strong phase separation between NonOx and PhOx allowing the NonOx chains to orient to the surface. © 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 47: 6433–6440, 2009     

Synthesis and characterization of new low bandgap polyfluorene copolymers for bulk heterojunction solar cells

Two new low bandgap alternating polyfluorene copolymers based on dioctylfluorene and donor‐acceptor‐donor monomers have been synthesized via a Suzuki polymerization reaction. The resulting copolymers have low optical bandgaps at 1.99–1.98 eV. The bulk heterojunction polymer solar cells were fabricated with the conjugated polymers as the electron donor and 6.6‐phenyl C₆₁‐butyric acid methyl ester as the electron acceptor. The power conversion efficiencies of the solar cells based on copolymers 1 and 2 are 0.37 and 0.42%, respectively, under the illumination of AM 1.5, 100 mW/cm². The results indicate that the two copolymers are promising conjugated polymers for polymer solar cells. © 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 47: 5336–5343, 2009     

Development of hydrogenated ring‐opening metathesis polymers

New hydrogenated ring‐opening metathesis polymers with excellent thermal and optical properties were developed. These polymers were prepared by the ring‐opening metathesis polymerization of ester‐substituted tetracyclododecene monomers followed by the hydrogenation of the main‐chain double bond. The degree of hydrogenation was an important factor for the thermal stability of the polymers, and as complete hydrogenation as possible was necessary to obtain a thermally stable polymer. The completely hydrogenated ring‐opening polymer derived from 8‐methyl‐8‐methoxycarbonyl‐substituted monomer has a glass‐transition temperature of 171 °C and a 5% weight‐loss temperature of 446 °C. This polymer has excellent thermal and optical properties because of its bulky and unsymmetrical polycyclic structure in the main chain and is an alternative to glass or other transparent polymers such as poly(methyl methacrylate) and polycarbonate resin. This polymer has also been used in a wide variety of applications, such as optical lenses, optical disks, optical films, and optical fiber. © 2000 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 38: 4661–4668, 2000     

Synthesis and white electroluminescent properties of multicomponent copolymers containing polyfluorene,oligo(phenylenevinylene), and porphyrin derivatives

Two novel multicomponent copolymers ( P1 and P2 ) containing polyfluorene (PF), oligo(phenylenevinylene) ( OPV ), and porphyrin ( Por ) derivatives were synthesized according to the Suzuki polymerization method. The structures, optical, and electrochemical properties of the two model compounds ( OPV and Por ) and multicomponent copolymers were characterized by ¹H NMR, FTIR, elemental analysis, UV–vis spectroscopy, photoluminescence, and cyclic voltammetry, respectively. Both of the copolymers exhibit thermotropic liquid crystalline properties and represent the characteristic Schlieren textures in a wide temperature range. Electroluminescence spectra of these copolymers exhibit broadband emissions covering the entire visible region from 400 to 700 nm. The single layer polymer light emitting diodes device based on P2 with a configuration of indium tin oxide/poly(ethylenedioxythiophene):poly(styrenesulfonic acid)/polymers/Ca/Al emits white light with the Commission Internationale de l′Eclairage chromaticity coordinates of (0.29, 0.30), maximum brightness of 443 cd/m². The white‐light‐emitting devices based on the novel multicomponent copolymers exhibit low turn‐on voltage, and good color stability at different driving voltages as well. © 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 47: 5291–5303, 2009     

Sulfonated poly(meta‐phenylene isophthalamide)s as proton exchange membranes

Random and block sulfonated poly(meta‐phenylene isopthalamide)s as proton exchange membranes were synthesized through the Higashi‐Yamazaki phosphorylation method. Polymers with different degrees of sulfonation from 40 to 100 mol percent were prepared by adjusting the molar feed ratio of 5‐sulfoisophthalic acid sodium salt (SIPA) and isophthalic acid (IPA) in the reaction with meta‐phenylene diamine. Creasable polymer films were obtained by casting DMSO polymer solutions and the membrane films could be exchanged to the proton form in strong acid. ¹H NMR spectroscopy and titration confirmed the degree of sulfonation. Thermogravimetric analysis demonstrated good thermal stabilities with 5% weight loss greater than 380 °C. The copolymers with low degrees of sulfonation (DS = 40 mol %) exhibited low water uptake (water uptake < 17 wt %) at room temperature. A segmented multiblock copolymer prepared by preforming a sulfonated block showed lower water uptake at high temperatures than the random polymer with the same DS of 40 mol % and displayed stability in water up to 80 °C. Both random and block copolymers showed higher proton conductivities at high temperature than that of Nafion‐117 under 95% relative humidity. © 2016 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2016 , 54, 2582–2592     

Radiolysis of resist polymers. III. Copolymers of methyl-α-chloroacrylate and trihaloethylmethacrylates

Homopolymers of 2,2,2-trifluoroethyl(methacrylate) (TFEMA) and 2,2,2-trichloroethyl-(methacrylate) (TCEMA) and copolymers with methyl-α-chloroacrylate (MCA) in a range of compositions were synthesized. The reactivity ratios were obtained; the two copolymerizations were close to ideal. Poly(MCA) showed G_s = 7.4 and G_s = 0.9 by γ-radiolysis. On the other hand, poly(TFEMA) and poly(TCEMA) and G_s values of 2.0 and 2.4, respectively, and G_x = 0. Radiolysis of copolymers was initiated to a large degree by dissociative electron capture by the halogen atoms in both comonomers, as revealed by the ESR spectra of radicals derived from them. Germinal recombinations in irradiated poly(TFEMA) suggested the presence of radicals in proximity. This process was absent in the copolymers. GC-MS analysis of volatile products and other supporting evidence showed that TFEMA monomers tended to depolymerize; the TCEMA monomers did not. The radiolysis yields varied monotonically with the comonomer composition for the MCA–TFEMA system but the yield–composition relationship was irregular in MCA–TCEMA copolymers. Four noncrosslinking systems are potential radiation resists arranged in increasing order of promise: poly(TFEMA) (G_s = 2.0, T_g = 70°); poly(TCEMA) (G_s = 2.7, T_g = 142°); poly(94MCA-co-6TCEMA) (G_s = 2.7, T_g = 142°); and poly(68MCA-co-32TFEMA) (G_s = 3.0, T_g = 112°). These materials merit further investigation for E-beam or x-ray lithographic applications. Mechanisms of radiolysis for these materials, based on ESR, GC-MS, and radiolysis yield data, were discussed.     

Poly(3‐hexyl thiophene)‐b‐poly(N‐isopropyl acrylamide): Synthesis and its composition dependent structural,solubility, thermoresponsive,electrochemical, and electronic properties

Conjugated block copolymers consisting of poly(3‐hexyl thiophene) (P3HT) and a thermoresponsive polymer poly(N‐isopropyl acrylamide) (PNIPAM) with varying composition have been synthesized by facile click reaction between alkyne terminated P3HT and azide terminated PNIPAM. The composition‐dependent solubility, thermoresponsive property in water, phase behavior, electrochemical, optical, and electronic properties of the block copolymers were systematically investigated. The block copolymers with higher volume fraction of PNIPAM form thermoresponsive spherical micelles with P3HT‐rich crystalline cores and PNIPAM coronas. Both X‐ray and atomic force microscopic studies indicated that the blocks copolymers showed well‐defined microphase separated nanostructures and the structure depended on the composition of the blocks. The electrochemical study of the block copolymers clearly demonstrated that the extent of charge transport through the block copolymer thin film was similar to P3HT homopolymer without any significant change in the band gap. The block copolymers showed improved or similar charge carrier mobility compared with the pure P3HT depending on the composition of the block copolymer. These P3HT‐b‐PNIPAM copolymers were interesting for fabrication of optoelectronic devices capable of thermal and moisture sensing as well as for studying the thermoresponsive colloidal structures of semiconductor amphiphilic systems. © 2016 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2016 , 54, 1785–1794     

Thermal and spectral stability of electroluminescent hyperbranched copolymers containing tetraphenylthiophene‐quinoline‐triphenylamine moieties

Fluorescent hyperbranched copolymers (HB‐x, x = 1–4) with inherent tetraphenylthiophene, triphenylamine (TPA) and quinoline (Qu) moieties were prepared to study the influence of the TPA branching point on the thermal and the spectral stability. All the HB‐x copolymers exhibited high glass transition temperatures (T_gs = 245–315 °C) with the detected values increasing with the increasing branching TPA content in the HB‐x. The solid HB‐x films possess high emission efficiency with the resulting quantum yields (?_Fs) in the ranges of 0.72–0.74. More importantly, the HB‐x copolymers and the derived light‐emitting devices exhibit high photoluminescence (PL) and electroluminescence (EL) stability towards thermal annealing at temperatures higher than 200 °C. After annealing at 200 °C (or 300 °C), no change was observed in the respective PL and EL spectra of HB‐1 (or HB‐4) copolymers. The spectral stability was found to correlate with T_g and with the highest branching density, HB‐4 copolymer possesses the highest thermal stability among all HB‐xs and show no EL spectral change after annealing at 300 °C for 4 h. The results indicate that all the branched HB‐x copolymers are promising candidates for the polymer light‐emitting diodes due to their high quantum yield and spectral stability. © 2011 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2012