Unsaturated polyesters based on bis(2-hydroxyethyl)terephthalate

A series of unsaturated polyesters based on bis(2-hydroxyethyl)terephthalate, ethylene glycol, propylene glycol, diethylene glycol, maleic anhydride and styrene were prepared. Properties of these castings were investigated and compared with those analogues based on dimethyl terephthalate or polyester oligomers formed by depolymerization of poly(ethylene terephthalate). It is found that properties of castings based on bis(2-hydroxyethyl)terephthalate are superior to those based on polyester oligomer. When compared with those based on dimethyl phthalate, the castings have higher hardness and heat distortion temperature, but lower tensile strength and elongation; other properties are very similar.     

Thermally reactive phenylethynyl-terminated bis(benzylester) and bis(amide) monomers based on semi-enzymatically produced 6-phenylethynyl picolinic acid

The synthesis and isolation of 6-phenylethynyl picolinic acid (PEPCA; IUPAC name: 6-(2-phenylethynyl)pyridine-2-carboxylic acid) was first demonstrated when Acinetobacter sp. strain F4 was used to biotransform diphenylacetylene to the ring-fission product that underwent facile ring closure to form PEPCA in the presence of ammonium ions. Here, the structure and properties of PEPCA were confirmed by comparison with those of PEPCA that was chemically synthesized. In the chemical route, commercially available 6-bromopicolinic acid was first converted to methyl 6-bromopicolinate using methyl iodide and 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU). The resulting methylester was coupled with phenylacetylene by the palladium-catalyzed reaction to yield methyl 6-phenylethynyl picolinate, which was then hydrolyzed by sodium carbonate to afford PEPCA. Both enzymatically and chemically synthesized PEPCA were used to prepare its thermally reactive bis(benzylester) and bis(amide) derivatives. Thus, three phenylethynyl-terminated bis(amide) derivatives were synthesized by treating PEPCA with 1,3-phenylenediamine, 4,4′-oxydianiline or 4,4′-(hexafluoroisopropylidene)dianiline via dicyclohexylcarbodiimide (DCC)-mediated amidation. The bis(benzylester) derivative was prepared from PEPCA and α,α′-dibromo-p-xylene. All the intermediates and final products were characterized by FT-IR, NMR, MS and elemental analysis. The thermal properties of PEPCA and the reactive derivatives were characterized by DSC and TGA. The exothermic peaks of three bis(amide) derivatives were at least 20-40 °C lower than typically reported for the phenylethynyl compounds. Lowered reaction temperatures observed for the thermally-induced free radical polymerization of phenylethynyl groups were attributed to the strong electron-withdrawing capability of the pyridine moiety. Bis(amide) derivatives exhibited excellent thermal stability after previously cured at 300 °C for 30 min and 350 °C for 30 min.     

Syntheses and properties of polyimides based on bis(p-aminophenoxy)biphenyls

Three biphenyl unit-containing diamines,4,4-bis(p-aminophenoxy)biphenyl (III_a), 2,2-bis(p-aminophenoxy)biphenyl (III_b), and 3,3,5,5-tetramethyl-4,4-bis(p-aminophenoxy)biphenyl (III_c), were prepared by the chlorodisplacement ofp-chloronitrobenzene with 4,4-biphenol (I_a), 2,2-biphenol (I_b), and 3,3,5,5-tetramethyl-4,4-biphenol (I_c), respectively, giving the corresponding bis(nitrophenoxy) compounds II_a-c, followed by catalytic reduction with palladium (Pd) and hydrazine. Three series of polyimidesp-PI,o-PI, and Me-PI were prepared from diamines III_a-c and aromatic tetracarboxylic dianhydrides via a two-stage procedure that included ring-opening polyaddition to give poly(amic acid)s followed by thermal cyclodehydration to polyimides. The resultant three series of poly(amic acid)s had inherent viscosities of 1.09–2.83, 0.78–1.93, and 1.55–3.09 dL/g, respectively. Almost all the poly(amic acid)s could be solution-cast and thermally converted into transparent, flexible, and tough polyimide films. All the polyimides were characterized by solubility, tensile test, wide-angle X-ray scattering measurements, differential scanning calorimetry (DSC), and thermogravimetric analysis (TGA). Effects of the structures of aromatic diamines and dianhydrides on the properties of polyimides were investigated.     

Facile access to enantiomerically pure bis(sulfoxide) chelates of late transition metals

Herein contains a report detailing the synthesis and characterization of six, chiral, late-transition metal complexes all chelated using R_S,R_S-bis(p-tolylsulfinyl)ethane, R_S,R_S-BTSE. All complexes revealed S-ligation to the metal with an expected contraction of the sulfinyl-oxygen bond length when compared to free sulfoxide. The presented data serve to illustrate three attractive, yet unexplored, aspects of the bis(sulfoxide) bidentate ligand: (i) bidentate sulfoxide ligands, when chelated to a metal, give rise to complexes that are pseudo-C₂ symmetric in terms of both sterics and electronics, (ii) the sulfoxides, unlike typical N-, P-, and O-based ligands, present the coordination sphere with a significant amount of steric and electronic mismatch, and (iii) the data support the fact that sulfoxides are moderate σ-donors and good-to-excellent π-acceptors – an aspect that should afford such metal chelates with a wide degree of reactivity. Finally, X-ray crystallographic experiments, coupled with an extensive CCDC search, provide an opportunity to establish the following ligand-ranking scheme for bidentate ligands spanned by an ethylene bridge, R₂N–<RS(O)–<RS–<R₂P–, based on the trans influence of chloride salts of Pt(II).     

Epoxy–imide resins based on bis (carboxyphthalimide)s

Epoxy–imide resins have been obtained through the reaction of Araldite GY 250 (diglycidylether of bisphenol-A and epichlorohydrin; difunctional) and Araldite EPN 1138 (Novolac-epoxy resin; polyfunctional) with bis(carboxyphthalimide)s derived from 4,4′-diaminodiphenylsulfone, 3,3′-diaminodiphenylsulfone, 4,4′-diaminodiphenylmethane and 4,4′-diaminodiphenylmethane and trimellitic anhydride. For each epoxy-imide resin system, epoxy equivalent to carboxy equivalent ratio has been optimised to obtain the maximum tensile lap shear adhesive strength on stainless steel substrates at room temperature. The lap shear strength at 100, 150, and 175°C has been determined for the optimum ratio. Araldite EPN-1138-based systems give the lap shear strength of 141–182 kg/cm² at room temperature for the optimum compositions and retain about 84–100% of the lap shear strength at 150°C. Araldite GY-250-based systems have lap shear strength of 183–193 kg/cm² and retain 76–84% of the lap shear strength at 150°C except for the one cured with bis (carboxyphthalimide) prepared from 4,4′-diaminodiphenylmethane, which retains only 17% of the lap shear strength. Among the systems studied, Araldite GY 250 cured with bis (carboxyphalimide) synthesized from 3,3′-diaminodiphenylsulfone appears to be the best, retaining 75% (138 kg/cm²) of the lap shear strength at 175°C.     

Synthesis and characterization of polyimides based on isopropylidene-containing bis(ether anhydride)s

Two bis(ether anhydride)s, 4,4′-[1,4-phenylenebis(isopropylidene-1,4-phenyleneoxy)]-diphthalic anhydride (IV _a) and 4,4′-[isopropylidenebis(1,4-phenylene)dioxy]diphthalic anhydride (IV _b), were prepared in three steps starting from the nucleophilic nitrodisplacement reaction of 4-nitrophthalonitrile with α,α ′-bis(4-hydroxyphenyl)-1,4-diisopropylbenzene (I _a) and 4,4′-isopropylidenediphenol (I _b) in N,N-dimethylformamide (DMF) in the presence of potassium carbonate. The bis(ether anhydride)s IV _a and IV _b were polymerized with various aromatic diamines to obtain two series of poly(ether amic acid)s VI _a–g and VII _a–g with inherent viscosities in the range of 0.30∼0.74 and 0.29∼1.01 dL/g, respectively. The poly(ether amic acid)s were converted to poly(ether imide)s VIII _a–g and IX _a–g by thermal cyclodehydration. Most of the poly(ether imide)s could afford flexible and tough films, and they showed high solubility in polar solvents such as N-methyl-2-pyrrolidone (NMP), N,N-dimethylacetamide, and m-cresol. The obtained poly(ether imide) films had tensile strengths of 45∼83 MPa, elongations-to-break of 6∼27%, and initial modulus of 0.6∼1.7 GPa. The T_gs of poly(ether imide)s VIII _a–g and IX _a–g were in the range of 194∼210 and 204∼243 °C, respectively. Thermogravimetric analysis (TG) showed that 10% weight loss temperatures of all the polymers were above 500 °C in both air and nitrogen atomspheres.     

Photosensitive poly(benzoxazole) based on precursor from diphenyl isophthalate and bis(o-aminophenol)

A new synthetic method for the preparation of poly(benzoxazole) (PBO) precursor, poly(o-hydroxyamide) (7) from bis(o-aminophenol) (5) and diphenyl isophthalate (6) has been developed. Polymer 7 was prepared by the polycondensation of 5 and 6 in 1-methyl-2-pyrrolidinone (NMP) at 185-205 °C. Model reactions were carried out in detail to elucidate appropriate conditions for the formation of 2-hydroxybenzanilide (3) from o-aminophenol (1) and phenyl benzoate (2). The photosensitive (PBO) precursor based on polymer 7 containing a 22% of benzoxazole unit and 30 wt% 1-{1,1-bis[4-(2-diazo-1-(2H)naphthalenone-5-sulfonyloxy)phenyl]ethyl}-4-{1-[4-(2-diazo-1(2H)naphthalenone-5-sulfonyloxy)phenyl]methylethyl}benzene (S-DNQ) showed a sensitivity of 110 mJ cm⁻² and a contrast of 5.0 when it was exposed to 436 nm light followed by developing with a 2.38 wt% aqueous tetramethylammonium hydroxide solution at room temperature. A fine positive image featuring 8 μm line and space patterns was observed on the film of the photoresist exposed to 200 mJ cm⁻² of UV-light at 436 nm by the contact mode.     

Ionic liquids and plastic crystals based on tertiary sulfonium and bis(fluorosulfonyl)imide

A new series of low-melting, low-viscosity, hydrophobic ionic liquids based on relatively small tertiary sulfonium cations ([R¹R²R³S]⁺, wherein R¹, R², R³ = CH₃ or C₂H₅, R³ = CH₂CH₂OCH₃, CH₂CH₂COOCH₃, CH₂CH₂CN) and bis(fluorosulfonyl)imide (FSI⁻) anion have been prepared and characterized. The important physicochemical and electrochemical properties of these salts, such as melting point, glass transition, viscosity, density, ionic conductivity, thermal and electrochemical stability, have been determined. The influence of structure variation in the tertiary sulfonium cations on the above physicochemical properties is discussed. Among these new salts, some of them show the desirable properties including low-melting points, low viscosities, and high conductivities, to be selected as potential candidates as electrolytes in energy devices, and two salts are ionic plastic crystals.     

Ethylene polymerization with homogeneous and heterogeneous catalysts based on bis(4‐fluorophenyl)methyl‐substituted bis(imino)pyridyliron complexes

A series of bis(4‐fluorophenyl)methyl‐substituted bis(imino)pyridyliron chloride complexes were immobilized on oxide supports. The kinetics of ethylene polymerization by both homogeneous and heterogeneous systems was followed, the catalysts mostly demonstrating high activities. The effect of the ligands nature and reaction conditions on the catalytic activities and molecular weights of the resultant polyethylenes was examined. In contrast to homogeneous systems, the supported iron complexes were found to exhibit high and stable activity upon activation with triisobutyl aluminium, producing high‐molecular‐weight polyethylene with good morphology. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 42674.     

Soft matter electrolytes based on polymethylmetacrylate dispersions in lithium bis(trifluoromethanesulfonyl)imide/1-butyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide ionic liquids

Ion transport in a polymer-ionic liquid (IL) soft matter composite electrolyte is discussed here in detail in the context of polymer-ionic liquid interaction and glass transition temperature. The dispersion of polymethylmetacrylate (PMMA) in 1-butyl-3-methylimidazolium hexafluorophosphate (BMIPF₆) and 1-butyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide (BMITFSI) resulted in transparent composite electrolytes with a “jelly-like” consistency. The composite ionic conductivity measured over the range −30 °C to 60 °C was always lower than that of the neat BMITFSI/BMIPF₆ and LiTFSI-BMITFSI/LiTFSI-BMIPF₆ electrolytes but still very high (>1 mS/cm at 25 °C up to 50 wt% PMMA). While addition of LiTFSI to IL does not influence the glass T_g and T_m melting temperature significantly, dispersion of PMMA (especially at higher contents) resulted in increase in T_g and disappearance of T_m. In general, the profile of temperature-dependent ionic conductivity could be fitted to Vogel-Tamman-Fulcher (VTF) suggesting a solvent assisted ion transport. However, for higher PMMA concentration sharp demarcation of temperature regimes between thermally activated and solvent assisted ion transport were observed with the glass transition temperature acting as the reference point for transformation from one form of transport mechanism to the other. Because of the beneficial physico-chemical properties and interesting ion transport mechanism, we envisage the present soft matter electrolytes to be promising for application in electrochromic devices.     

Synthesis and identification of bis (diacylglycero) phosphoric acid and bis (monoacylglycero) phosphoric acid

Synthesis of bis-(diacylglycero)phosphoric acid fromsn-1,2-dipalmitoylglycerol and phenylphosphoryl dichloride according to Baer (1) was revised. New data are reported about identification of the intermediate and final products: (a) bis-phosphatidic acid phenyl ester is very slowly visualized by the Zinzade reagent and can escape notice; (b) large amounts of phosphatidic acid chloride phenyl ester are also formed; and (c) very little transacylation fromsn-1,2-dipalmitoyl-glycerol to the 1,3-isomer is observed. Hydrolysis of bis-phosphatidic acid to bis-lysophosphatidic acid is much easier using phospholipase A₂ from pig pancreas than from snake or bee venom.     

Processable and colorless fluorinated poly(ether imide)s based on an isopropylidene‐containing bis(ether anhydride) and various aromatic bis(ether amine)s bearing trifluoromethyl groups

A series of novel organosoluble and light‐colored fluorinated poly(ether imide)s (PEIs) ( IV ) having inherent viscosities of 0.43–0.59 dL/g were prepared from 4,4′‐[1,4‐phenylenbis(isopropylidene‐1,4‐phenyleneoxy)]diphthalic anhydride ( I ) and various trifluoromethyl‐substituted aromatic bis(ether amine)s by a standard two‐step process with thermal and chemical imidization of poly(amic acid) precursors. These PEIs showed excellent solubility in many organic solvents and could be solution‐cast into transparent and tough films. These films were essentially colorless, with an UV–visible absorption edge of 361–375 nm and a very low b* value (a yellowness index) of 15.3–17.0. They also showed good thermal stability with glass‐transition temperature of 191–248°C, 10% weight loss temperature in excess of 494°C, and char yields at 800°C in nitrogen more than 39%. The thermally cured PEI films showed good mechanical properties with tensile strengths of 83–96 MPa, elongations at break of 8–11%, and initial moduli of 1.7–2.0 GPa. They possessed lower dielectric constants of 3.25–3.72 (1 MHz). In comparison with the V series nonfluorinated PEIs, the IV series showed better solubility, lower color intensity, and lower dielectric constants. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 104: 620–628, 2007     

Organosoluble poly(ether imide)s from phthalimidine based and trifluoromethyl substituted bis(ether amine)

A series of new organosoluble and optically transparent poly(ether imide)s (PEIs) were synthesized by the polycondensation of trifluoromethyl substituted and phthalimidine cardo group based bis(ether amine), 3,3‐bis‐[4‐{2′‐trifluoromethyl 4′‐(4″‐aminophenyl)phenoxy}phenyl]‐2‐phenyl‐2, 3‐dihydro‐isoindole‐1‐one with different fluorinated and non‐fluorinated aromatic dianhydrides (2a–e). All the PEIs were well characterized by elemental analysis, NMR, FTIR spectroscopy, and gel permeation chromatography (GPC). The synthesized PEIs showed moderate to high inherent viscosity 0.41–0.61 dL/g and excellent solubility at room temperature in different organic solvents. All the transparent yellow films showed cut‐off length upto 425 nm. They exhibited high tensile strengths upto 98 MPa, excellent thermostability upto 554°C for 5% weight loss, high glass transition temperature upto 327°C, and water uptake value less than 0.6%. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

Synthesis and characterization of bis (a-methyl-4-nitrobenzyl) peroxide and bis ( a-methyl-4-nitrobenzyl ) ether

以对硝基乙苯为原料,研究了合成标题化合物的方法,并对其进行了结构表征.在合成双-(α-甲基-4-硝基苄基)过氧化物的方法中,使用优选的T(p-OCH3) PPZn作为催化剂,原料的转化率可达16.2％,产物的选择性为44.0％,相应地收率达7.1％.其中以氧气作为氧化剂,使用金属卟啉为催化剂合成对硝基乙苯一步得到双-(α-甲基-4-硝基苄基)过氧化物的方法尚未见文献报道.     

Chemical synthesis of graphite bis(perfluoropinacolato)borate and graphite bis(hexafluorohydroxyisobutyrato)borate intercalation compounds

Graphite chelate borate intercalation compounds, C_xB[OC(CF₃)₂C(CF₃)₂O]₂ · δF and C_xB[OC(CF₃)₂C(O)O]₂ · δF, are prepared for the first time by chemical oxidation of flaky graphite with fluorine gas in the presence of a solution of the intercalate anion in anhydrous hydrofluoric acid. Powder XRD data indicate that products up to stage 1 with gallery heights, d_i = 1.43-1.45 nm are formed. The compositions of C_xB[OC(CF₃)₂C(CF₃)₂O]₂ · δF and C_xB[OC(CF₃)₂C(O)O]₂ · δF are determined using B and F elemental analyses. Thermogravimetric analyses indicate the graphene sheets begin to decompose before intercalate thermolysis is complete.     

Flame retardant epoxy resins based on diglycidyl ether of isobutyl bis(hydroxypropyl)phosphine oxide

Phosphorous‐containing epoxy resins were prepared from diglycidyl ether of isobutyl bis(hydroxypropyl)phosphine oxide (IHPOGly) and diglycidyl ether of bisphenol A (DGEBA) by crosslinking with 2,4‐diaminotoluene. Several IHPOGly/DGEBA molar ratios were used to obtain materials with different phosphorous content. Thermal, dynamomechanical, and flame retardant properties were evaluated and related with the phosphorous content. The weight loss rate of phosphorous‐containing resins is lower than that of the phosphorous‐free resin for the thermoxidative degradation. Char yields under nitrogen do not show significant differences among the phosphorous‐containing resins and the phosphorous‐free resin, while under air char yields increase with the phosphorous content. The presence of phosphorous increases the limiting oxygen index (LOI) values even when the phosphorous content is low, and no significant differences with the phosphorous content are observed. V‐0 materials were obtained when the resins were tested for ignition resistance with the UL‐94 test. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 99: 1367–1373, 2006     

Effect of copolycondensation temperature on the reactivity ratios of bis(4-hydroxybutyl) terephthalate and bis(2-hydroxyethyl) terephthalate

Summary The effect of copolycondensation temperature on the monomer reactivity ratios of bis(4-hydroxybutyl) terephthalate (BHBT) and bis(2-hydroxyethyl) terephthalate (BHET) was investigated at 260, 270, and 280 °C, in the presence of titanium tetrabutoxide as a catalyst. Adopting 2nd order kinetics to polycondensation, the rate constants of polycondensation of BHBT and BHET, k ₁₁ and k ₂₂, were calculated to be 2.58, 1.30; 3.87, 2.24; and 5.29, 4.06 min⁻¹. In addition, the rate constants k ₁₂ and k ₂₁ of cross reactions could be determined as 0.91, 3.00; 1.49, 4.42; and 2.13, 5.85 min⁻¹ from a proton nuclear magnetic resonance spectroscopic analysis. The monomer reactivity ratios of BHBT were much larger than those of BHET, indicating the block nature of the copolycondensation, but the differences between monomer reactivity ratios were decreased with increasing polycondensation temperature, indicating that a probability of randomization was increased. Received: 15 October 1998/Revised version: 3 December 1998/Accepted: 8 December 1998     

Organic sulfur compounds,III. Addition products of ethylene oxide to bis(2-hydroxyethyl)disulfide

The composition of products resulting from the reaction of bis(2-hydroxyethyl)disulfide with ethylene oxide in the presence of sodium methoxide, dimethyl cyclohexylamine and boron trifluoride etherate as catalysts was determined. The addition reactions were carried out at 80°C, under normal and increased pressure, using the reagents in molar ratios of 1:1. Under these conditions the degree of disulfide conversion varied within the 70–80% range. Oxyethylene derivatives of bis(2-hydroxyethyl)disulfide were the main products of the investigated reaction. Additionally, slight amounts of ethylene glycols (2–4%) and sulfides (2–4%) were found resulting from a reaction of ethylene oxide with the decomposition products of the starting disulfide.     

Kinetics of copolycondensation of bis(4-hydroxybutyl) terephthalate and bis(2-hydroxyethyl) terephthalate by ester-interchange reaction

The kinetics of polycondensation and copolycondensation reactions were investigated using bis(4-hydroxybutyl) terephthalate (BHBT) and bis (2-hydroxyethyl) terephthalate (BHET) as monomers. BHBT was prepared by ester interchange reaction of dimethyl terephthalate and 1,4-butanediol. BHBT and BHET were polymerized at 270°C in the presence of titanium tetrabutoxide (TBT) as a catalyst. Applying second-order kinetics for polycondensation, the rate constants of polycondensation of BHBT and BHET, k₁₁ and k₂₂, were calculated as 3.872 min⁻¹ and 2.238 min⁻¹, respectively. BHBT and BHET were also copolymerized at 270°C using TBT. The rate constants of crossreactions in the copolycondensation of BHBT and BHET, k₁₂ and k₂₁, were obtained by using the results obtained from a proton nuclear magnetic resonance (¹H-NMR) spectroscopy and a high-performance liquid chromatography (HPLC). It was found that the rate constants during the copolycondensation of BHBT and BHET at 270°C decreased in the order k₂₁ > k₁₁> k₂₂ > k₁₂ and the monomer reactivity ratio of BHBT was four or five times larger than that of BHET. In calculating the crossreactions, the method by the ¹H-NMR spectroscopy gave more accurate results than that by the HPLC. © 1996 John Wiley & Sons, Inc.