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Polymethyl methacrylate (PMMA)/Congo Red (CR) and polyvinyl chloride (PVC)/CR composite films were prepared on optical glass by the drop method for optical measurements and also prepared as tablets under pressure for dielectrical measurements. The optical transmission spectra measurements for PMMA and PVC film doped with CR showed a highly absorption in the ultraviolet-visible (UV-Vis) optical range (at 353 nm and 518 nm) and considerably blocking in broad visible range (190 nm–640 nm). PMMA/CR and PVC/CR composite films containing congo red at a concentration of 1 wt% showed maximum absorption bands at 290 nm and 416 nm, but their transmittance percentages were reasonably reduced compared to those of pure PMMA and PVC. Both of composites indicated high transmittances between 640 nm and 800 nm. The optical constants of the PMMA/CR and PVC/CR composite films such as optical band energy gaps (Eg) estimated using Tauc's model, refractive index and reflectance (%) were calculated. UV–Vis, Fourier transform infrared spectroscopy (FTIR) and Thermogravimetry Analysis (TGA) measurements were used to confirm the breakdown of the -N = N- azo group bonds attached to the aromatic ring as a result of thermal decomposition of CR at 500 °C, and it was suggested that N2 gas was eliminated from the CR above 360 °C. The dielectric plots showed that the dielectric constant increased when the CR is doped up to 70 wt% in the polymer matrices. A further increase in the doping concentration of CR resulted in an increase of the dielectric constant. The dielectric constant decreased with an increase in the frequency for all of the samples. The ac (alternating current) conductivity values of PMMA and PVC showed an increase with increasing CR dopant in the polymer composites, while the ac conductivity values were found to be values between those of the pure polymers and CR. [ABSTRACT FROM AUTHOR]

The copolymer precursor, poly [4-(4-vinylbenzyl)oxy)phthalonitrile]-co-methyl methacrylate (poly (VBOPN-co-MMA)), was synthesized through copolymerization of VBOPN and MMA at a temperature of 110°C. Subsequently, a single-chain polymer complex of cobalt phthalocyanine (SCP-CoPc) was formed at 150°C by intramolecular macrocyclization between the cobalt and the phthalonitrile group in poly (VBOPN-co-MMA), using excess cyclohexanol. The formation of the SCP-CoPc complex was confirmed through various spectroscopic techniques such as UV/Vis, FT-IR, 1H-NMR, and 13C-NMR. In particular, the disappearance of -CN band at 2232 cm−1 from FT-IR indicated the formation of the SCP-CoPc complex, while the presence of specific absorption bands in the UV/Vis spectrum further confirmed its creation. The electrical, dielectric, optical, and thermal properties of the SCP-CoPc complex and SCP-CoPc/ZnO 5% composites were investigated. The SCP-CoPc/ZnO 5 wt% nanocomposite exhibited improved dielectric and DC conductivity with increasing temperature. The activation energy (Ea) was found to be 0.35 eV for SCP-CoPc and 0.25 eV for SCP-CoPc/ZnO 5 wt% nanocomposite, indicating that the electrical conductivity followed the Arrhenius equation. The optical properties, including band gap, dielectric constant, and refractive index, were calculated for the SCP-CoPc/ZnO 5 wt% nanocomposite. The SCP-CoPc complex possessed a band gap of 2.89 eV, while the SCP-CoPc/ZnO 5 wt% nanocomposite had a slightly reduced band gap of 2.36 eV. The refractive indices of SCP-CoPc and SCP-CoPc/ZnO 5 wt% were also determined. [ABSTRACT FROM AUTHOR]

Poly[4‐((4‐vinylbenzyl)oxy) phthalonitrile‐co‐methyl methacrylate] [P(VBOPN10.7%‐co‐MMA)] was prepared by atom transfer radical polymerization (ATRP) method at 110°C. Green colored single chain polymer molecule via intramolecular formation of zinc phthalocyanine (SCP‐ZnPc) on polymer chain was synthesized using VBOPN as a precursor copolymer under conditions of dilute cyclohexanol and at 140–150°C. The successful formation of zinc phthalocyanine on a single chain molecule was confirmed using Fourier‐transform infrared spectroscopy (FT‐IR) and UV/Vis spectroscopy techniques. Nanogaphene‐based SCP‐ZnPc composite was prepared to employ 6 weight (wt)% of total weight and were investigated its thermal, electrical, dielectric and optical properties. The dielectric and DC electrical conductivity of SCP‐ZnPc/NG 6 wt% nanocomposite were found to increase depending upon temperature. And the conduction obeyed the Arrhenius relationship with the activation energy, Ea values for I. and II. regions were 0.345 eV and 0.275 eV, respectively. The optical constants (refractive index, real value of optical dielectric constant) and the optical band gap of SCP‐ZnPc/NG 6 wt% were estimated. The direct band gap and refractive index of SCP‐ZnPc/NG 6 wt% were estimated, and its direct band gap was estimated as 2.7 eV. [ABSTRACT FROM AUTHOR]

Atom transfer radical polymerization (ATRP) of three-armed polystyrene[PS] and poly(styrene-b-isobutyl methacrylate)[PS-b-PiBμMA] were accomplished using an initiator with tri-active C-Br end group function and cuprous (I) bromide/2,2'-bipyridyne catalytic system. The characterization obtained by FT-IR, [.sup.1]H-NMR, and GPC techniques. The average molecular weight and polydis-persity of PS and PS-b-PiBμMA were determined as 19,800, 29,300 and as 1.37 and 1.15, respectively, which indicates that the constant concentration of growing chains are present throughout the polymerization. The refractive index and extinction coefficient of the samples were determined in the visible range as a function of wavelength. The refractive index dispersion curves of the thin films were fitted by the Cauchy-Sellmeier model. The width of localized states ([E.sub.u]) values changed inversely with optical band gaps ([E.sub.g]) of the films. While the calculated [E.sub.u] values of films for initiator, PS and PS-b-PiBμMA were determined as 2.72, 2.98, and 2.94 eV, the [E.sub.g] values were determined as 3.43; 3.11, and 3.16 eV, respectively. The dispersion parameters of thin films were determined. These parameters changed in the investigated wavelength ranges. POLYM. ENG. SCI., 50:268-277, 2010. [C] 2009 Society of Plastics Engineers, INTRODUCTION Optical plastics (1) are an important article of commerce and are used widely to make substrates for optical storage devices, such as compact discs and digital video discs, optical [...]

Poly(2-hydroxyethyl methacrylate) (PHEMA) and TiO2 nanoparticles (NPs) containing polymeric nanocomposites (PNCs) in different mass ratios of TiO2 (3, 5 and 7%) with respect to PHEMA were synthesized by using the in-situ polymerization/hydrothermal method. The prepared composite materials were characterized by SEM, FTIR, UV–Vis, TGA and XRD techniques. The results of the characterization experiments showed that the composite successfully synthesized and TiO2 in the polymer matrix is well distributed, especially for the lowest TiO2 contained composite (3% TiO2). The thermal activation energies (Ea) of the PNCs were estimated by the Ozawa, Kissinger, and Kissinger–Akahira–Sunose methods by using non-isothermal TGA experiments. By increasing the amount of TiO2 nanoparticles, the thermal stability and glass transition temperature (Tg) of PHEMA was increased. The water holding capacity of PNCs was determined by swelling experiments. As the amount of TiO2 in the PNCs increased, the degree of swelling decreased. In addition, the swelling values ​​of both PHEMA and PNCs increased with increasing the temperature. The dielectric constant (Ɛ′), the dielectric loss factor (Ɛ′′) and ac conductivity of neat PHEMA and PNCs were also measured for the frequency range of 100 Hz to 2 kHz and for the temperatures of 30 and 180 °C. It was obtained that the frequency dependence of the dielectric constant and dielectric loss factor decreased with increasing frequency. Finally, the biological activities of PNCs against gram-positive (S. aureus) and gram-negative (E. coli) bacteria were also tested and it was observed that this effect increased with the amount of TiO2. [ABSTRACT FROM AUTHOR]

2-(Naphthalene-1-yl oxy)-2-oxoethyl methacrylate (NOEMA) was synthesized from reaction of naphthalene-1-yl 2-chloroacetate and sodium methacrylate and its homopolymer was prepared by free-radical polymerization method at 60°C. The glass transition temperature of pure poly(NOEMA) was estimated as 102°C by differential scanning calorimetry technique, whereas that of poly(NOEMA) containing 10 wt% nanographene was 83°C. While pure poly(NOEMA) from thermogravimetric analysis measurements was indicating a decomposition at 290°C, poly(NOEMA) composite containing 10 wt% nanographene showed thermal decomposition temperature at 261°C. Semiconducting composites of poly(NOEMA) have been prepared by adding nanographene particles to poly(NOEMA) for preparing nanocomposites with different weight percentages (2, 3, 4, 5, and 10 wt%). The dielectric constant, ∊ ′, and dielectric loss factor, ∊ ″, of pure poly(NOEMA) were 3.66 and 0.052, respectively, whereas those of poly(NOEMA) containing 10 wt% nanographene were 186 and 210,152, respectively. Alternating current (AC) conductivity of pure poly(NOEMA) was 2.03 × 10−9 S cm−1, whereas that of poly(NOEMA) containing 10 wt% nanographene was 0.00134 S cm−1. AC conductivity mechanism of poly(NOEMA)/10 wt% nanographene composite indicated the correlated barrier hopping model. Activation energy values of poly(NOEMA)/ x wt% nanographene composites was estimated to be between 4.783 eV and 0.209 eV. The polymer composite/p-Si thin-film heterojunction diode properties have been investigated from current–voltage at room temperature. The electrical parameters of the prepared diodes such as ideality factor (n), the barrier height (BH; Φ b), rectification ratio, and reverse saturation current (I o) were investigated at dark and room temperature. The ideality factor (n) value of the Al/poly(NOEMA)/ x wt% nanographene/p-Si/Al diode for dark was found to be between 5.147 and 7.504, respectively. The BH (Φ b) value of the Al/poly(NOEMA)/ x wt% nanographene/p-Si/Al diode at dark was found to be between 0.228 and 0.64. [ABSTRACT FROM AUTHOR]

Poly[Ɛ-CL-b-(MMA-comb-EMA)]comb-type polymers were synthesized by ATRP and Ɛ-caprolactone macroinitiator and macromonomer. Methyl methacrylate macromonomer was synthesized from acylation reaction of methacryloyl chloride with PMMA ended 7-hydroxy coumarin. The macroinitiator was prepared from the reaction of chlorine acetyl chloride P(Ɛ-CL). The synthesized polymers were characterized by FT-IR, 1H-NMR and 13C-NMR techniques. The average molecular weight and molecular weight distribution of polymers were measured by GPC method. Thermal properties of samples were studied by DSC/TGA techniques. Dielectric and Ac conductivity measurements were performed. Dielectric constant (ɛˈ), dielectric loss factor (ɛˈˈ) and conductivity behaviors of comb-type polymer were measured at room temperature between the frequency of 100–2000 Hz and over the temperature range 303–413 K at 1 kHz reported as compared with each other. Besides, their effects on the electrical properties by doping with EuCl3 for some of the comb copolymers were and were investigated. The activation energy (Ea) was calculated from conductivity. We reported it was determined that the (ɛˈ) and (ɛˈˈ) values decreased with increasing frequency. There are also many application areas for comb polymers for example; nanotechnology, medicine. The aim of this study is to synthesize comb-type copolymers in different compositions and to investigate their electrical properties. [ABSTRACT FROM AUTHOR]