Preparation of polymide-imides by direct polycondensation with triphenyl phosphite. V. Aliphatic-aromatic polyamide-imides based on N,N′-bis(ω-carboxyalkyl) benzophenone-3,3′,4,4′-tetracarboxylic diimides

Five diimide-dicarboxylic acids were prepared from benzophenone-3,3′,4,4′-tetracarboxylic dianhydride and glycine, β-analine, 4-aminobutyric acid, 6-aminocaproic acid, and 11-aminoundecanoic acid. New aromatic-aliphatic polyamide-imides were prepared by the direct polycondensation of these diacids with aromatic diamines using triphenyl phosphite in N-methyl-2-pyrrolidone (NMP)–Pyridine solution in the presence of calcium chloride. The resulting polymers were characterized by inherent viscosity, infrared spectra, elemental analyses, solubility, differential scanning calorimetry (DSC), thermogravimetry, and wideangle x-ray diffraction measurements.     

Preparation and properties of aromatic polyamides from 5-t-butylisophthalic acid and various aromatic diamines

Aromatic polyamides (aramids) having pendant t-butyl group were synthesized by the direct polycondensation of 5-t-butylisophthalic acid with various aromatic diamines in N-methyl-2-pyrrolidone (NMP) using triphenyl phosphite and pyridine as condensing agents. The aramids having inherent viscosities of 0.6–2.4 dL/g were obtained in quantitative yields. These polymers were readily soluble in various solvents such as NMP,N,N-dimethylacetamide, dimethyl sulfoxide, and pyridine, and gave transparent, tough and flexible films by casting from the NMP solutions. The aramids had glass transition temperatures between 250 and 330°C, and started to lose weight around 350°C, with 10% weight loss being recorded at about 450°C in air.     

Preparation and properties of polyarylates from 5-t-butylisophthaloyl chloride and various bisphenols

Polyarylates containing a t-butyl pendant group were prepared from 5-t-butylisophthaloyl chloride and various bisphenols through the phase-transfer catalyzed two-phase polycondensation. The polyarylates having inherent viscosities up to 3.1 dL/g were obtained quantitatively. They were readily soluble in various solvents such as chloroform, m-cresol, and pyridine. Coloreless, transparent, and flexible films could be cast from the chloroform solutions of the polymers. The polyarylates had glass transition temperatures between 210 and 320°C, and did not lose weight below 350°C, with 10% weight loss being recorded at 395–450°C in air.     

Synthesis and properties of novel poly(amide-imide)s containing pendent diphenylamino groups

A new dicarboxylic acid, 2,4-bis(N-trimellitoyl)triphenylamine, bearing two preformed imide rings was synthesized from the condensation of 2,4-diaminotriphenylamine and trimellitic anhydride at 1:2 molar ratio. A series of poly(amide-imide)s (PAIs) with inherent viscosities of 0.38-0.66 dl/g were prepared by triphenyl phosphite-activated polycondensation from the diimide-dicarboxylic acid with various aromatic diamines. All the resulting PAIs were readily soluble in a variety of organic solvents and formed strong and tough films via solution casting. These PAIs have useful levels of thermal stability associated with moderately high glass-transition temperatures (259-314 °C) and 10% weight loss temperatures in excess of 530 °C in nitrogen or in air.     

Syntheses and properties of 4-hydroxy-3,5-dibromobenzyl phosphonates and their flame-retarding effects on ABS copolymer

4-Hydroxy-3,5-dibromobenzyl phosphonates (HDBBP) were synthesized by reacting phosphites with 4-hydroxy-3,5-dibromobenzyl bromide (HDBBB) which was prepared in advance by photobromination of 2,6-dibromo-p-cresol (DBPC) produced by bromination of p-cresol. In the reactions between HDBBB and phosphites, the rate of formation of dimethyl 4-hydroxy-3,5-dibromobenzyl phosphonate (HDBBP_m) was greater than that of diphenyl 4-hydroxy-3,5-dibromobenzyl phosphonate (HDBBP_P); however, quantitative yields for both products were obtainable. The addition of HDBBP as bromine and phosphorus containing flame-retardants to ABS copolymer showed better results than the addition of the same amount of brominated compound, or mixtures of both two compounds. It was also proved that compound containing both bromine and phosphorus exhibited more apparent synergistic effects on flame retardancy than the mixtures of brominated compound and phosphorous containing compound     

Applications of the finite difference mode solution method to photonic crystal structures

The finite difference waveguide mode solution method, which has been popularly employed in the study of waveguide modes on various optical and dielectric waveguides, is utilized to calculate the modal characteristics of photonic crystal fibers (PCFs) and planar photonic crystal waveguides and the band diagrams of two-dimensional photonic crystals. Vector guided modes on both PCFs based on the total internal reflection guiding mechanism ('holey fibers') and those resulting from photonic band gap effect are accurately computed, with their effective indexes and field distributions compared with other methods. Calculated dispersion of a single-core holey fiber and coupled-power behavior of a two-core holey fiber are found to agree with measured results. For applications to band diagram calculation and planar photonic crystal waveguide analysis, the finite difference scheme is modified simply by imposing suitable periodic boundary condition. Numerical results for air-column crystals and dielectric-rod crystals are both found to agree well with calculations using other methods.     

硒化镉发光量子点的制备及其在有机发光器件中的应用

硒化镉量子点具有随粒径尺寸改变,而产生发光波长调变的特性,目前已被广泛研究。本研究是由化学溶胶法合成不同粒径尺寸的核壳型CdSe／ZnS硒化镉量子点,其表面包覆十六烷基胺,避免分子团聚现象。在由硒化镉成核温度的控制,成功地制备一系列具有各种尺寸粒径的核壳型硒化镉量子点(2—6nm)。本研究也合成了含有纳米金粒子于核壳型硒化镉量子点,实验结果发现：硒化镉发光效率明显的提高。在有机发光器件的应用方面,将发光波长为505nm核壳型CdSe／ZnS量子点掺入溶有发光波长为570nm铱化合物的氯仿溶液时,其溶液的光致发光光谱表明,原量子点的发光特性消失,只有铱化合物的发光依然存在,且其发光强度呈现明显增强趋势,我们推测此现象源自于量子点到铱化合物能量转移的机制。我们也以含有核壳型硒化镉量子点的铱化合物与PVK混合材料为发光层,成功的制作发光二极管器件,器件的发光效率因核壳型硒化镉的掺杂,明显提高2倍多。     

New poly(amide-lmide)s syntheses. XV. Preparation and properties of poly(amide-imide)s derived from 9, 9-bis[4-(4-aminophenoxy) phenyl]fluorene and various bis(trimellitimide)s

Fifteen bis(phenoxy) fluorene-containing poly(amide-imide)s III were synthesized by the direct polycondensation of 9,9-bis[4-(4-aminophenoxy)phenyl]fluorene (BAPPF) with var-ious aromatic bis(trimellitimide)s II in N-methyl-2-pyrrolidone (NMP) using triphenyl phosphite and pyridine as condensing agents. Poly(amide-imide)s III having inherent vis-cosities up to 1.45 dL/g were obtained in quantitative yields. Most of the resulting polymers showed an amorphous nature and were readily soluble in polar solvents such as NMP and N,N-dimethylacetamide. All the soluble poly(amide-imide)s afforded transparent, flexible, and tough films. The glass transition temperatures of these polymers were in the range of 263–315°C and the 10% weight loss temperatures were above 510°C in nitrogen. Some properties of poly(amide-imide)s III were compared with those of the corresponding isomeric poly(amide-imide)s III ′ prepared from 9,9-[4-(4-trimellitimidophenoxy)phenyl]fluorene and various aromatic diamines. © 1995 John Wiley & Sons, Inc.     

Syntheses and properties of aromatic polyamides and polyimides derived from 9,9-bis[4-(p-aminophenoxy)phenyl]fluorene

9,9-Bis[4-(p-aminophenoxy)phenyl]fluorene ( II ) was used as a monomer with various aromatic dicarboxylic acids and tetracarboxylic dianhydrides to synthesize polyamides and polyimides, respectively. The diamine II was derived by a nucleophilic substitution of 9,9-bis(4-hydroxyphenyl)fluorene with p-chloronitrobenzene in the presence of K₂CO₃ and then hydro-reduced. Polyamides IV _a-g having inherent viscosities of 0.73–1.39 dL/g were prepared by the direct polycondensation of the diamine II with various aromatic diacids using triphenyl phosphite and pyridine as condensing agents. All the aromatic polyamides were amorphous and readily soluble in various polar solvents such as N,N-dimethylacetamide, N,N-dimethylformamide, dimethylsulfoxide, and N-methyl-2-pyrrolidone. Transparent and flexible films of these polymers could be cast from the DMAc solutions. These aromatic polyamides had glass transition temperatures in the range of 283–309°C and 10% weight loss occurred up to 460°C. The polyimides were synthesized from diamine II and various aromatic dianhydrides via the two-stage procedure that included ring-opening poly-addition in DMAc to give poly(amic acid)s, followed by thermal or chemical conversion to polyimides. The poly(amic acid)s had inherent viscosities of 0.62–1.78 dL/g, depending on the dianhydrides. Most of the aromatic polyimides obtained by chemical cyclization were found to be soluble in NMP. These polyimides showed almost no weight loss up to 500°C in air or nitrogen atmosphere. © 1993 John Wiley & Sons, Inc.     

13C-NMR Spectra of 2- and 3-Phthalimido-3(2)-Benzimidazolylpropanoic Acid and 2- and 3-Phthalimidobenzimidazopyrrolone,Reaction Products of Phthaloylaspartic Anhydride with Ortho-Phenylenediamine

Two pairs of isomers of 3- and 2-phthalimido-3(2)benzimidazolylpropanoic acid (V and VI) and 2- and 3-phthalimidobenzimidazopyrrolone (VII and VIII) were produced from the reaction of phthaloylaspartic anhydride (I) with o-phenylenediamine (II). The ¹³C-NMR spectra of V and VI both showed 11 carbon signals indicating that the structures of their benzimidazole groups were symmetric. Isomers V and VI were easily distinguished from each other by the chemical-shift-differences (Δδ) of the methylene carbon and the methine carbon. Compounds VII and VIII displayed 14 carbon signals and no longer showed the symmetric structure of the benzimidazole moity, The chemical-shift-differences (Δδ) between methylene carbon and methine carbon in pyrrolones of VII and VIII can also be used to distinguish VII from VIII. The Δδ of compound VII is less than that of compound VIII.