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High Optical Transparency (high + optical_transparency)
Selected AbstractsFlexible nanocrystalline-titania/polyimide hybrids with high refractive index and excellent thermal dimensional stabilityJOURNAL OF POLYMER SCIENCE (IN TWO SECTIONS), Issue 6 2010Guey-Sheng Liou Abstract In this study, a novel synthetic route was developed to prepare polyimide,nanocrystalline,titania hybrid optical films with a relatively high titania content (up to 50 wt %) and thickness (20,30 ,m) from soluble polyimides containing hydroxyl groups. Two series of newly soluble polyimides were synthesized from the hydroxy-substituted diamines with various commercial tetracarboxylic dianhydrides. The hydroxyl groups on the backbone of the polyimides could provide the organic,inorganic bonding and resulted in homogeneous hybrid solutions by controlling the mole ratio of titanium butoxide/hydroxyl group. AFM, SEM, TEM, and XRD results indicated the formation of well-dispersed nanocrystalline-titania. The flexible hybrid films could be successfully obtained and revealed relatively good surface planarity, thermal dimensional stability, tunable refractive index, and high optical transparency. A three-layer antireflection coating based on the hybrid films was prepared and showed a reflectance of less than 0.5% in the visible range indicated its potential optical applications. © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 48: 1433,1440, 2010 [source] Novel amorphous perfluorocopolymeric system: Copolymers of perfluoro-2-methylene-1,3-dioxolane derivativesJOURNAL OF POLYMER SCIENCE (IN TWO SECTIONS), Issue 5 2006Yu Yang Abstract Perfluorotetrahydro-2-methylene-furo[3,4- d][1,3]dioxole (monomer I) and perfluoro-2-methylene-4-methoxymethyl-1,3-dioxolane (monomer II) are soluble in perfluorinated or partially fluorinated solvents and readily polymerize in solution or in bulk when initiated by a free-radical initiator, perfluorodibenzoyl peroxide. The copolymerization parameters have been determined with in situ19F NMR measurements. The copolymerization reactivity ratios are rI = 1.80 and rII = 0.80 in 1,1,2-trichlorotrifluoroethane at 41 °C and rI = 0.97 and rII = 0.85 for the bulk polymerization. These data show that this copolymerization pair has a good copolymerization tendency and yields nearly ideal random copolymers. The copolymers have only one glass-transition temperature from 101 to 168 °C, depending on the copolymer compositions. Melting endotherms have not been observed in their differential scanning calorimetry traces, and this indicates that all the copolymers with different compositions are completely amorphous. These copolymers are thermally stable (the initial decomposition temperatures are higher than 350 °C under an N2 atmosphere) and have low refractive indices and high optical transparency from UV to near-infrared. Copolymer films prepared by casting were flexible and tough. These properties make the copolymers ideal candidates as optical and electrical materials. © 2006 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 44: 1613,1618, 2006 [source] Synthesis and characterization of aromatic/cycloaliphatic poly(amide- imide-imide)s from bis(4-amino- 3,5-dimethylphenyl) cycloalkane derivativesPOLYMER INTERNATIONAL, Issue 8 2007Bhuvana Sowrirajalu Abstract A series of novel aromatic diamines containing cycloaliphatic moieties was synthesized by the reaction of cycloalkanones like cyclohexanone and cycloheptanone with 2,6-dimethylaniline. The tetrimide diacid was synthesized using the prepared diamine with 3,3,,4,4,-benzophenonetetracarboxylic acid dianhydride/pyromellitic dianhydride and p -aminobenzoic acid. The polymers were prepared by treating the tetrimide diacid with different aromatic diamines. The structures of the monomers and polymers were identified using elemental analysis and Fourier transform infrared, 1H NMR and 13C NMR spectroscopy. The polymers show excellent solubility. The polymers are amorphous and have high optical transparency. They also show good thermal stability and their Tg value is found to be in the range 268,305 °C. Copyright © 2007 Society of Chemical Industry [source] Novel Soluble Polyimide Containing 4- tert- Butyltoluene Moiety: Synthesis and CharacterizationCHINESE JOURNAL OF CHEMISTRY, Issue 11 2009Chenyi Wang Abstract Based on the synthesis of a rigid aromatic diamine, ,,, -bis(4-aminophenyl)-4-(t- butyl)toluene (1), a novel polyimide (PI) 3 was prepared from this diamine monomer and 4,4,-oxydiphthalic dianhydride via a one-step high-temperature polycondensation. FT-IR, 1H NMR and elemental analysis were used to investigate the chemical structures of 1 and 3. The results confirmed that they agreed with the proposed structures for both 1 and 3 completely. The obtained PI 3 showed excellent solubility in most common solvents such as N -methyl-2-pyrrolidinone, N,N -dimethylacetamide, N,N -dimethylformamide, chloroform, dichloromethane and tetrahydrofuran. The resulting strong and flexible film exhibited high thermal stability with the glass transition temperature at 317°C and the temperature at 10% weight loss beyond 519°C in both air and nitrogen atmospheres. Moreover, the film also showed high optical transparency, low dielectric constant (3.13 at 1 MHz), low water absorption (0.40%) and hydrophobic character. [source] | ||||||||||