Synthesis and characterization of azo–bisbenzylidene‐based polymers for second order nonlinear optics

Main chain polymers containing azo and bisbenzylidene moiety were synthesized by polycondensation method. The successful polymerization reaction was characterized by UV–vis absorption, FT‐IR and NMR spectroscopy. The resulting polymers were soluble in polar solvents like dimethyl formamide (DMF) and showed good thermal stability up to 250 °C. These polymers were blended with poly methyl methacrylate (PMMA) and corona poled for characterizing second harmonic generation (SHG) property. Temperature stability study of SHG intensity of poled polymer showed that it is stable up to 80 °C. To improve temperature stability further the crosslinking of polymer under UV light is proposed. © 2013 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2013, 51, 4317–4324     

Synthesis of linseed oil based biodegradable homo and copolymers: role as multifunctional greener additives in lube oil

Abstract

Homopolymer of linseed oil and its four copolymers with styrene, 1-decene, isodecyl acrylate and octyl acrylate, respectively, have been synthesized in this present context. The prepared polymers are characterized by NMR and FTIR spectroscopy. The molecular weights have been measured by gel permeation chromatography. Their effectiveness as pour point depressant (PPD), viscosity index improver (VII) and their shear stability in terms of permanent shear stability index have been evaluated in lube oil. The copolymers acted as better PPDs than the homopolymer whereas the homopolymer of linseed oil excelled as VII. Further it was observed that all the prepared polymers were stable enough under severe mechanical shear.     

9位芳香基取代超支化聚芴的合成与表征

以2,7-二溴芴酮为起始原料,在芴的9位引入芳香取代基代替传统的烷基取代基,增加9位的稳定性,并用AB+AB2的方法,用新单体合成了不同支化度的超支化聚合物,新合成的超支化聚合物具有良好的热稳定性和发光稳定性.聚合物的热分解温度都在400℃以上;聚合物的薄膜在空气中于200℃加热2 h后没有出现绿光发射带,发光稳定性和烷基聚芴相比得到明显的提高.DSC结果显示,线性聚合物在170℃时有玻璃化转变,超支化聚合物在300℃以内没有明显的相转变,保持一种稳定的无定形态,更有利于提高材料的发光效率.     

New benzimidazole-2-yl-substituted polybenzimidazoles: Synthesis, properties, and hydrodynamic characteristics

The synthesis of novel benzimidazole-2-yl-substited polybenzimidazoles and initial compounds has been described. The polymers are studied by FTIR spectroscopy, TGA, and TMA. The hydrodynamic properties of macromolecules are investigated by translational diffusion and viscometry in 96% H₂SO₄; the molecular characteristics of the polymers are determined. Positive temperature dependences for intrinsic viscosities of the polymers are obtained. The polymers under study possess high hydrolytic stability with respect to sulfuric acid solutions up to 150°C and high thermal stability in the bulk. The TGA data correlate with the chemical structure of the polymers. The new polybenzimidazoles may be used as materials for the production of medium-temperature proton-conducting membranes.     

Synthesis and characterization of benzocyclobuten-4-yl acrylate monomer and its radical polymerization

<正>A benzocyclobuten-4-yl acrylate(1) monomer was prepared by esterification of 4-hydroxybenzocyclobutene with acryloyl chloride.The radical homopolymerization of 1 and copolymerization of 1 with styrene or n-butyl acrylate were carried out to produce linear polymers 2a,2b and 2c.Heating of these linear polymers under thermal initiation gave corresponding cross-linked polymers 3a,3b and 3c.The ring-opening reaction in the cross-linking process was confirmed by on-line infrared spectra.Differential scanning calorimetry showed that the glass transition temperatures of linear polymers 2a and 2b were 83.2℃and 68.1℃,respectively.Thermogravimetric analysis of the cross-linked polymers showed that they all exhibited good thermal stability.     

Polymers containing anthraquinone units: Benzimidazole and benzothiazole polymers

In an attempt to synthesize soluble polymers, diphenyl 1,5-anthraquinonedicarboxylate was treated with 3,3′-dimercaptobenzidine and 3,3′-diaminobenzidine under various conditions. Although the ester reacted readily, side reactions prevented the formation of high molecular weight compounds. It was thought that at the elevated temperatures required for reaction, the quinone group was involved in a type of Schiff's base formation. The thermal stability of the polymers was evaluated. Model compounds were prepared and their absorption spectra were compared with those of the polymers. It was observed that 1,5-anthraquinonebibenzimidazole-2 formed a stable product with acetic acid. Some of the polymers could be solubilized by reduction with sodium dithionite in alkali, but no useful fibers were produced from these solutions.     

Synthesis and characterization of poly(benzobisthiazole)s derived from halogenated phthalic acid and isophthalic acid

Poly(benzobisthiazole)s containing tetrafluorophenyl and bromophenyl moieties were synthesized via the polycondensation of 2,5‐diamino‐1,4‐benzenedithiol dihydrochloride with tetrafluorophthalic acid and 4‐bromoisophthalic acid under a nitrogen atmosphere. The polymers were characterized by X‐ray diffraction, spectroscopy (infrared and solid‐state ¹³C NMR), and thermal analysis, including differential scanning calorimetry and thermogravimetric analysis. The thermogravimetric analysis showed that the thermal stability of the polymers was 490–515 °C under a nitrogen atmosphere. The synthesized polymers showed good solubility in organic solvents. © 2002 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 40: 3959–3966, 2002     

Synthesis and Properties of Highly Photoluminescent and Electrochemically Active Polymers Containing 2‐Pyrazoline Units in the Main Chain

Summary: Two new polymers containing 2‐pyrazoline units in the main chain were synthesized for the first time by a Suzuki polycondensation between a 2‐pyrazoline monomer and aryl diboronic esters. The polymers showed high photoluminescence (PL) in both the solution and the solid state; quantum yields of PL in toluene were higher than 76%. Thermogravimetric analysis and cyclic voltammetry showed that the polymers had high thermal stability and good reversibility under electrochemical oxidation.

New polymers ( 2 and 3 ) with strong photoluminescence and good reversibility under electrochemical oxidation were synthesized here.     

Thermal Analysis of Some Environmentally Degradable Polymers

The thermal characteristics of a series of degradable polymers have been investigated using thermogravimetry and differential scanning calorimetry. While the results of the thermogravimetry experiments suggest that the thermal stability of the polymers should not pose any problems at the temperatures that can be expected in a commercial composting process (60°C), phase changes associated with some of the polymers investigated may cause problems in the interpretation of data from composting degradation studies. Several biodegradable polymers were observed to have melt transitions at temperatures similar to those found in a composting environment. Consequently, under the controlled composting conditions used to evaluate biodegradable polymers, degradation of a polymer may be inferred, while actually the polymer has merely undergone a phase change. This revised version was published online in July 2006 with corrections to the Cover Date.     

芳香族二胺聚合物的合成及其性能

<正> 在导电性有机固体研究领域中导电聚合物的研究占有不可忽视的地位,特别是70年代以来聚苯胺及其掺杂物导电性的发现更加引起了人们对有机导体的极大兴趣,人们从聚合物的合成到性能的表征展开了广泛研究,主要工作集中在聚苯胺、聚吡咯等各种合成方法及电性能表征方面。有关芳香族多胺聚合物的合成及表征却很少见文献报道,Tsuchida等人曾报道了在铁盐与含氮化合物形成的络合物存在下对苯二胺及对苯二酚氧化聚合得到具有顺磁性、电导率为10~(-10)Scm~(-1)的聚合物。80年代末期Torrance报道了在较缓和的条件下均苯三胺聚合可以得到铁磁性聚合物,本文对三种苯二胺聚合物的合成及其电性能、热稳定性能等做了初步研究。     

Preparation of Functional Long-Subchain Hyperbranched Polystyrenes via Post-polymerization Modification: Study on the Critical Role of Chemical Stability of Branching Linkage

Post-polymerization modification (PPM) is one of the most powerful strategy for preparing polymers with functional groups that cannot be synthesized by direct polymerization. So far, numerous experimental efforts have been devoted to the stability issue of monomer structures during the PPM process, but little attention was paid to chemical linkages. However, for hyperbranched polymers, a minor change of linkage unit could lead to a significant influence on the overall stability and performance of polymer materials. In this work, we investigated the chemical stability of long-subchain hyperbranched polystyrenes with ester, aryl ether, and carbon-carbon bonds as branching linkages under a few most popular PPM conditions, including NaOH hydrolysis reaction, TFA-promoted hydrolysis reaction, BBr₃-catalyzed methoxy-hydroxyl conversion reaction, and LiAlH₄ carbonyl reduction reaction. Related results are summarized into a synthetic route map that can provide practical and intuitive guidance for preparing functional long-subchain hyperbranched polystyrenes and other type of polymers by PPM for future applications.     

Construction of optical active metallo-supramolecular polymers from enantiopure bis-pybox ligands

Two types of optical active metallo-supramolecular polymers were successfully constructed from the complexation of two enantiopure bis-pyridine-dioxazole (bis-pybox) ligands and 3d transition metal ions such as Zn²⁺ and Fe²⁺ in organic solution. The self-assembly process was investigated via UV–vis and fluorescent titration. The chiral characteristic of polymers was detected by circular dichroism. It was revealed that the phenyl-substituted polymers showed higher stability than the benzyl-substituted ones. Temperature-dependent circular dichroism spectra demonstrated the dynamic structure of this type polymer under the variation of temperature. This work highlights the opportunity in designing and constructing of the optical active metallo-supramolecular polymers from the organic privilege ligands in the field of asymmetric catalysis.     

Novel fluorinated poly(aryl ether ketone)s

Two novel fluorinated monomers were prepared and polymerized with biphenols to produce amorphous, thermally stable poly(aryl ether ketone)s. The properties of the fluorinated polymers are compared to those of unfluorinated, amorphous poly(aryl ether ketone)s. The presence of fluorine in the polymers was found to cause a decrease in glass transition temperature and Young's moduli, however, no increase in thermal stability was observed. The fluorinated polymers are soluble in common organic solvents such as chloroform and methylene chloride at room temperature, and also show solubility in solvents containing a ketonic moiety, such as acetone. Evidence of polymer branching through fluorines considered to be unreactive under the polymerization conditions was found. Efforts were made to evaluate the reactivity of fluorine atoms under the polymerization conditions using both molecular modeling and ¹⁹F-NMR to ascertain if such branching could be avoided. © 1995 John Wiley & Sons, Inc.     

Synthesis and characterization of mono‐ and di‐methoxy substituted acrylate polymers containing photocrosslinkable pendant chalcone moiety

Two acrylate monomers – 4‐(2′‐methoxycinnamoyl)phenyl acrylate, and 4‐(2′,5′‐dimethoxycinnamoyl)phenyl acrylate – comprising photocrosslinkable pendant chalcone moiety and a free radical polymerizable group were synthesized. The monomers were polymerized in the presence of ethyl methyl ketone at 70°C using benzoyl peroxide as the initiator. The polymers were characterized by UV, FT‐IR, ¹H‐NMR, and ¹³C‐NMR spectra. The weight and number average molecular weights of the polymers were determined by gel permeation chromatography. The thermal stability of the polymers was studied by TGA under a nitrogen atmosphere. Glass transition temperatures of the polymers were studied by differential scanning calorimetry. The photoreactivity of the polymers was investigated for potential applications as photoresists in solution using various solvents. Copyright © 2008 John Wiley & Sons, Ltd.     

Preparation of some new polybenzimidazoquinazolines

Several new types of polybenzimidazoquinazolines with a different recurring unit have been prepared by solution polycondensation in polyphosphoric acid followed by heating at elevated temperature under reduced pressure. The polymers thus obtained were light yellow to brown powdery materials hardly soluble in common organic solvents and soluble in concentrated sulfuric acid. The inherent viscosity of the polymers ranged from 0.1 to 0.58 and showed good thermal stability.     

含苯乙炔的可自交联高温高性能聚芳醚酮的合成与性能

将可交联的苯乙炔结构引入到热塑性聚芳醚酮链中, 并对其交联前后的性能进行了深入研究.     

Use of microperlite in direct polymerization of lactic acid

PLA is one of the most frequently used biodegradable polymers. In this work, PLA was synthesized by direct condensation polymerization of lactic acid in the presence of microperlite to obtain enhanced thermal stability of PLA polymer. Molecular weights of the synthesized polymers were determined by GPC. Chemical structure analyses was done by FTIR. The degree of crystallinity was evaluated by DSC and XRD. Thermal stability of polymers was investigated by DSC and TGA. It has been observed that the existence of perlite has significantly increased the crystallinity and degradation temperature, therefore, enhanced the thermal stability of the PLA.     

Synthesis of chromophore‐embedded polyurethanes for electrooptical materials

We carried out the polyaddition of dye‐embedded diols with diisocyanates to obtain novel nonlinear optical (NLO) polyurethanes, where the NLO units were embedded in the polymer backbone. The obtained polymers showed high glass‐transition temperatures (138–184 °C) and thermal stability (temperature of 10% weight loss under nitrogen = 227–287 °C). The λ maximum of the polymers was 521–556 nm. © 2001 John Wiley & Sons, Inc. J Polym Sci Part A: Polym Chem 39: 2620–2624, 2001     

Towards the development of multisensor for drugs of abuse based on molecular imprinted polymers

The synthetic receptors for cocaine, deoxyephedrine, methadone and morphine were computationally designed and produced using molecular imprinting. The structure and energy of the molecular complexes were analysed by computational techniques. The possible structures of the binding sites in the synthetic receptors have been compared with those of corresponding natural receptors. The composition of imprinted polymers was optimised to allow adequate performance under the same experimental conditions. All selected molecular imprinting polymers (MIPs) demonstrated stronger affinity in comparison with corresponding blank polymers resulting in imprinted factors (I) equal to 1.2 (cocaine), 2.5 (deoxyephedrine), 3.5 (methadone) and 3 (morphine) which suggested that the specific binding site for each molecule was successfully created. The polymers studied possessed good selectivity and affinity towards their templates and could be recommended for the integration with sensor devices. From a practical point of view, especially for multisensor requirements, the synthetic receptors based on imprinted polymers could be superior to natural receptors due to their stability, robustness and compatibility with automation processes required for sensor fabrication.     

Synthesis, characterization, thermal and optical properties of styrene derivatives having pendant p-substituted benzylic ether groups

The derivatives of styrene monomer, 4-chlorophenyl-4-vinylbenzyl ether (M1), 4-methoxyphenyl-4-vinylbenzyl ether (M2), 4-ethylphenyl-4-vinylbenzyl ether (M3) and 1-naphtylphenyl-4-vinylbenzyl ether (M4) were synthesized. The normal free radical polymerization of monomers in 1,4-dioxane were performed by using 2,2′-azobisisobutyronitrile as an initiator at 65 °C. The monomers and their homopolymers were characterized by FT-IR, NMR and elemental analyses measurements. The thermal stability of polymers was investigated by thermogravimetric and differential scanning calorimetric analysis. Thermal degradation activation energies of the polymers were calculated by the Ozawa and Kissinger methods. In addition, photo-stability tests of the polymers under near-UV irradiation were performed.