Bibenzoic Acid Research Articles

Versatile monometallic coordination polymers constructed from 4,4′-thiobis(methylene)bibenzoic acid and 1,10-phenanthroline. Synthesis, structure, magnetic and luminescence properties

Four novel mononuclear coordination polymers [Co(tmba)(phen)(H2O)0.5]n (1), [Mn(tmba)(phen)]n (2), [Zn(tmba)(phen)]n (3) and [Cd(tmba)(phen)(H2O)]n (4), H2tmba = 4,4′-thiobis(methylene)bibenzoic acid, phen = 1,10-phenanthroline, were synthesized under hydrothermal conditions and characterized by single crystal X-ray diffraction, powder X-ray diffraction, infrared spectroscopy, and thermogravimetric analysis. Single crystal X-ray diffraction showed that compounds 1, 3 and 4 build 1D chains whereas complex 2 displays a 2D layer configuration. Magnetic susceptibility measurements indicate that compound 1 exhibits the coexistence of spin–orbit coupling and antiferromagnetic interaction in the binuclear Co(II) center. Compound 2 manifests an antiferromagnetic interaction within the Mn(II)-carboxyl chain. Moreover, based on the solid state emission spectra of compounds 3 and 4, and of H2tmba and phen, relevant fluorescence properties have been investigated.

Relationship between Sequence Length and Thermal Properties of Poly(ethylene Terephthalate-Co-4, 4’-Bibenzoate) (PETBB)

Poly(ethylene terephthalate-co-4,4’-bibenzoate)s (PETBBs) with 0-25mol% bibenzoate unit were prepared from terephthalic acid (PTA), 4,4'- bibenzoic acid (BBA) and ethylene glycol (EG). The chemical composition and number-average sequence length of the resultant PETBBs were investigated by 13C-NMR. It was improved that the chemical composition of PETBBs is identical with the feed ratio, and the number-average sequence length of PET segment (LPET) becomes reduced with increasing BBA unit. The molecular weights of PETBBs reaches the high level for practical use. DSC analysis explains that the glass transition temperature (Tg) increases almost linearly and the crystallization becomes difficulty with increasing content of BBA unit. X-ray diffraction also illustrates that both crystallinity and crystal size reduced as more BBA unit is incorporated. Moreover, the relationship between the number-average sequence length and the melting temperature was investigated. The linear correlation between the number-average sequence length (LPET) and the melting temperature was observed.

Supramolecular main-chain liquid crystalline polymers and networks with competitive hydrogen bonding: a study of flexible bis-acids and a mixture of rigid and flexible polypyridyls

A series of novel liquid crystalline supramolecular networks formed through hydrogen bonds have been synthesised. These networks are based on flexible bi-benzoic acid and two types of pyridyl species – a small rigid bipyridyl capable of forming liquid crystalline phases and polyfunctional non-mesogenic pyridyl species that can compete for available hydrogen bond donor molecules. It was found that the networks display monotropic nematic character at high concentrations of disrupting net points – up to 50% for tetrapyridyls, 40% for tripyridyls and 35% for bipyridyls. Weak smectic phases were observed in all systems in loadings up to 10% of each disrupting unit. It is believed that the reversibility of the hydrogen bond allows for the formation of the ordered mesophases in the presence of the non-liquid crystalline groups.

Biphenyl-2,2'-diyl 구조를 함유하는 Copolyterephthalamides의 합성과 성질

디아민으로서 p-phenylene diamine, 4,4'-oxydianiline, 1,4-bis(4-aminophenoxy)benzene에 대해 이염기산으로서 terephthalic acid와 2,2'-bibenzoic acid를 혼합 사용하여, 주쇄에 Biphenyl-2,2'-diyl 구조를 갖는 copolyterephthalamide를 직접중축합법에 의해 합성하였다. 얻어진 공중합체는 <TEX>$0.46{\sim}0.93dL/g$</TEX>의 본성점도를 나타내었으며, 이들 대부분은 N,N-dimethylacetamide와 N-methyl-2-pyrrolidone과 같은 범용 유기용매에 용해하였고, 유리전이온도는 <TEX>$239^{\circ}C$</TEX>와 <TEX>$326^{\circ}C$</TEX> 사이의 값을 나타냈으며, 질소기류하 10% 열분해 온도는 <TEX>$410{\sim}485^{\circ}C$</TEX>였다. Three series of copolyterephthalamides having biphenyl-2,2'-diyl structure in the main chain, were synthesized from p-phenylene-containing diamines such as p-phenylene diamine, 4,4'-oxydianiline or 1,4-bis(4-aminophenoxy)benzene, with mixed diacids of terephthalic acid and 2,2'-bibenzoic acid by the direct polycondensation method. The resulting copolymers had inherent viscosities ranging from 0.46 to 0.93dL/g, and most of them could be readily dissolved in polar aprotic solvents including N,N-dimethyl acetamide and N-methyl-2-pyrrolidone. These copolymers had glass transition temperatures between 239 and <TEX>$326^{\circ}C$</TEX>, and their 10% weight loss temperatures were recorded in the range of <TEX>$410{\sim}485^{\circ}C$</TEX> in nitrogen atmosphere.

Oxygen‐transport properties of liquid‐crystalline polyesters based on 4,4′‐bibenzoic acid

AbstractThis study examined the oxygen‐transport properties of aromatic liquid‐crystalline (LC) polyesters of 4,4′‐bibenzoic acid (BB) and an aliphatic diol. The effect of the spacer length was probed by the number of methylene groups in the diol being increased from 3 to 6. Parallel studies were performed on polymers in which the LC character was reduced or removed by copolymerization with 30 mol % nonmesogenic isophthalic acid (BB‐30I) or by the replacement of BB with 4,4′‐oxybis(benzoic acid) (OBB). The oxygen‐transport properties were interpreted in terms of the solid‐state structure as revealed by the thermal behavior and wide‐angle X‐ray diffraction. The strong odd–even effect of the spacer length that characterized the thermal transitions of the BB polyesters was weak or absent from the oxygen‐transport properties when the effect of crystallinity was considered. Permeability and diffusivity tended to increase with the spacer length. The lower oxygen permeability of all the BB polyesters compared with that of the BB‐30I copolyesters and the OBB polyesters was due primarily to lower oxygen solubility. The low solubility of the noncrystalline LC phase was ascribed to a smaller free‐volume hole size and possibly to a lower free‐volume hole density in comparison with an amorphous glass. The solubility of oxygen in the noncrystalline regions of the BB‐30I copolyesters and in the amorphous OBB polyesters conformed to the relationship between the solubility and the glass‐transition temperature previously established for amorphous and glassy aromatic polyesters. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 105: 30–37, 2007

Future directions for the research and development of polyesters: From high-performance to environmentally friendly

Abstract We discuss the future directions for the research and development of polyester-based materials. In the discussion of polyesters as industrial materials, one direction is the development of high-performance materials. Poly(ethylene terephthalate) (PET), known as one of the most important polyesters, was developed early in the 1940s. We discuss two approaches to the development of high-performance materials suitable for injection-molding applications using PET units. The first approach is development of high-performance materials by copolymerization with bibenzoic acid (BB), which has a rigid structure, and the second approach is development of liquid-crystal polyesters (LCPs) with superior thermal resistance and excellent flowability using PET units. The other future direction for research and development is the targeting of environmentally friendly materials. Poly(lactic acid) (PLA), derived from bio-based materials, is a very important material because it can realize the carbon neutral cycles. Nevertheless, the practical properties of PLA itself are unsatisfactory compared to other plastics derived from fossil resources. We have developed PLA-based polymer alloys with various practical properties by utilizing a newly developed nanoalloy technology.

Synthesis and properties of copolyesters of p,p′‐bibenzoic acid, dimer acid, and alkylene glycol

AbstractCopolyesters of p,p′‐bibenzoic acid, dimer acid, and an alkylene glycol are prepared by melt polycondensation of of dimethyl p,p′‐bibenzoate, dimer acid, and an alkylene glycol. The copolyesters are characterized by the inherent viscosity, FTIR, proton NMR, DSC, polarized microscopy, and X‐ray diffraction. The polymer composition and sequence distribution of the copolyesters can be seen from the NMR spectra. The copolyesters exhibit a degree of randomness of about 1, indicating that they are random copolymers. The glass‐transition temperature (Tg) and the melting point (Tm) of the copolyesters are found from the DSC heating curves. When the content of the flexible dimer acid unit increases, the Tg of the copolyesters decreases significantly. The copolymerization effect decreases the crystallinity and the Tm of the copolyesters. It can be seen from the DSC, polarized microscopy, and X‐ray diffraction data that some copolyesters derived from 1,6‐hexanediol and 1,5‐pentanediol exhibit a monotropic smectic phase. As the molar content of the dimer acid unit increases, the isotropic–mectic transition temperature and the smectic order decreases significantly. The liquid crystallinity is completely destroyed at certain molar contents of the dimer acid unit. The smectic order of the copolyesters derived from 1,6‐hexanediol is significantly higher than that of the copolyesters derived from 1,5‐pentanediol, and it is described as an odd–even effect. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 88: 750–758, 2003

Crystallization kinetics and crystalline morphology of poly(ethylene naphthalate) and poly(ethylene terephthalate‐co‐bibenzoate)

AbstractCopolymers of ethylene glycol with 4,4′‐bibenzoic acid and terephthalic acid are known to crystallize rapidly to surprisingly high levels of crystallinity. To understand this unusual behavior, the isothermal crystallization of poly(ethylene bibenzoate‐co‐terephthalate) in the molar ratio 55:45 (PETBB55) was studied. Poly(ethylene naphthalate) (PEN) was included in the study for comparison. The kinetics of isothermal crystallization from the melt and from the amorphous glass was determined using differential thermal analysis. The results were correlated with the crystalline morphology as observed with atomic force microscopy (AFM). Crystallization of PEN exhibited similar kinetics and spherulitic morphology regardless of whether it was cooled from the melt or heated from the glass to the crystallization temperature. The Avrami coefficient was close to 3 for heterogeneous nucleation with 3‐dimensional crystal growth. The copolymer PETBB55 crystallized much faster than did PEN and demonstrated different crystallization habits from the melt and from the glass. From the melt, PETBB55 crystallized in the “normal” way with spherulitic growth and an Avrami coefficient of 3. However, crystallization from the glass produced a granular crystalline morphology with an Avrami coefficient of 2. A quasi‐ordered melt state, close to liquid crystalline but lacking the order of a recognizable mesophase, was proposed to explain the unusual crystallization characteristics of PETBB55. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 86: 98–115, 2002

Thermotropic Polyesters with Flexible Spacers Bearing Ether Bonds in Asymmetric Position

The synthesis of several polyesters from p,p‘-bibenzoic acid and diols bearing ether bonds in asymmetric positions is described. The polyesters develop smectic mesophases, the type of which depends on the chemical structure of the spacer. The ether groups and the asymmetry of the spacers stabilize the liquid crystalline order in these polymers. Glass transition and isotropization temperatures, enthalpies, and entropies of the thermotropic polyesters are reported. Comparison of the melting entropies with the conformational entropies of the chains suggests a great disorder in the mesophases of thermotropic polyesters. For some polyesters, the stretched polymer chains do not follow the direction of the fiber axis, an unusual phenomenon that has already been described for some polybibenzoates with aliphatic separators. The influence of the strain rate on the anomalous flow is discussed.

The Oxidative Coupling of Methyl Benzoate

The reaction of methyl benzoate (MBA) with pressurized (50 atm) artificial air (50 mol% O2–N2 mixture) at 150–200°C over a soluble palladium catalyst [PdLL2′] (L=phen, bipy, dppe; L′=OAc, TFA) afforded isomeric dimethyl bibenzoic acid esters (DMBBA). Different factors affect the reactivity and regioselectivity of the process. The reactivity is enhanced by trifluoromethanesulfonic acid, arguably by activating the C–H bond of the aromatic ring by its protonation. The increase of temperature not only increases the reaction rate (EA=5.5 kcal/mol) but also favors a formation of an ortho-coupled product. Ligands with strong trans influence (L=phen, bipy, or dppe) direct the oxidative coupling away from 2,X′-isomers (X=2, 3, or 4). Overall, electronic properties of a palladium catalyst are more important than steric restriction of the same catalyst for altering the activity and regioselectivity for MBA coupling.

Synchrotron X-ray Study of the Phase Transitions in Liquid Crystal Polyesters Derived from p,p‘-Bibenzoic Acid and racemic- and (R)-3-Methyl-1,6-hexanediol

The phase transitions in two liquid crystalline polyesters have been studied by diffraction techniques employing synchrotron radiation. The two polyesters, derived from p,p‘-bibenzoic acid and 3-methyl-1,6-hexanediol, only differ on the optical activity of the chiral spacer: both the active and racemic polymers have been investigated. Time-resolved experiments at variable temperature were performed, analyzing the cooling from the isotropic melt and the subsequent melting. The analysis of the different diffraction profiles (covering WAXS, MAXS, and SAXS regions) shows important differences in the phase behavior of the two polyesters, more important than those anticipated from the analysis of the DSC curves. Nevertheless, a common feature is the obtention of SC mesophases in both polymers, characterized by a continuous increase of the tilting angle as the temperature is decreased (before the appearance of high-order mesophases).

Pressure-Induced Crystal Polymorph of Thermotropic Polyesters Composed of p,p‘-Bibenzoic Acid and Penta- and Hexamethylene Diols

Pressure-Induced Crystal Polymorph of Thermotropic Polyesters Composed of <i>p,p</i>‘-Bibenzoic Acid and Penta- and Hexamethylene Diols

Synthesis and phase behaviour of liquid crystalline polyesters derived from p, p′-bibenzoic acid and meso and R-3-methylhexanediol

The synthesis and thermal properties of two new liquid crystalline polyesters derived from bibenzoic acid and (R,S)- or (R)-3-methyl-1,6-hexanediol are reported. The phase behaviour was investigated by means of differential scanning calorimetry, X-ray diffraction and polarizing microscopy. The effect of the asymmetry introduced by the branched methyl group and that of the stereoisomerism on the type and stability of the mesophases formed are analysed. Both polymers exhibited smectic mesophases of different types depending on thermal history. The presence of an optically active pure diol along the chain gives rise to a more regular structure in comparison with the polymer synthesized from the racemic mixture.

Dynamic mechanical relaxations of liquid crystalline copolyesters derived from bibenzoic acid

Viscoelastic relaxations have been studied in thermotropic copolyesters synthesized by transesterification of diethyl p,p′ -bibenzoate and different ratios of triethylene glycol (TEG) and 1,8-octanediol. A liquid crystal glass is obtained in these copolymers by fast quenching from the isotropic melt, as revealed by d.s.c. and X-ray measurements. Three relaxations, α, β and γ in order of decreasing temperature, appear in all the samples. The α relaxation is identified as the glass transition of the mesophase, and the results are compared with those obtained from d.s.c. measurements. The glass transition temperature of the mesophase of these copolymers shows a relationship with the composition similar to that for amorphous copolymers. The shape, intensity and temperature location of the α relaxation are very much dependent on the composition. More intense and sharper α peaks, shifted to lower temperatures, are obtained when the TEG content increases. The β relaxation, associated with the carboxyl group, is also affected by the structure of the flexible oxyalkylene spacer. Finally, the γ relaxation shifts to slightly lower temperatures when the TEG content increases.

Thermotropic liquid crystal polyesters derived from 4,4′‐biphenyldicarboxylic acid and oxyalkylene spacers

AbstractSeveral polyesters derived from bibenzoic acid and oxyalkylene glycols have been prepared and the ability of formation of mesophases was studied. The phase behaviour was investigated by means of differential scanning calorimetry, wide‐angle X‐ray diffraction and real‐time variable‐temperature small‐angle X‐ray diffraction. A common feature of all the studied polyesters, with ether groups in the spacer, is the inhibited ability for developing three‐dimensional structures, in contrast to the polymers with all‐methylene spacers. Moreover, the latter polymers show a monotropic mesophase behaviour but the former exhibit an enantiotropic transformation. Smectic structures of different types have been detected: The polyester derived from 3,3'‐oxybis(1‐propanol) produces a smectic SA structure, while the polyester from triethylene glycol leads to a smectic SC mesophase. The influence of the spacers on the dynamic mechanical relaxations of these polybibenzoates has been studied and discussed.

Fully aromatic thermotropic liquid crystalline polyesters of 3,4′‐dihydroxybenzophenone

AbstractA series of fully aromatic, thermotropic polyesters, derived from 3,4′‐dihydroxybenzophenone and various aromatic dicarboxylic acids, was prepared by the high‐temperature solution polycondensation method and examined for thermotropic behavior by a variety of experimental techniques. The aromatic dicarboxylic acids used in this study were 2,6‐naphthalenedicarboxylic acid, 4,4′‐bibenzoic acid, and terephthalic acid.The two homopolymers of 3,4′‐DHB with either 2,6‐NDA or 4,4′‐BBA formed nematic LC phases at 285°C and 255°C and also exhibited isotropization transitions (Ti) at 317°C and 339°C, respectively. The copolymer of 3,4′‐DHB with 50% TA and 50% 2,6‐NDA also formed a nematic LC phase and had a broader range of LC phase than that of its respective homopolymers. Two other copolymers of 3,4′‐DHB, both containing 50% 4,4′‐BBA, also formed nematic LC phases at low Tf values. All of the thermotropic polyesters had high thermal stabilities. © 1994 John Wiley &amp; Sons, Inc.

Preparation and properties of aromatic polymides from 2,2′‐bibenzoic acid and aromatic diamines

AbstractAromatic polyamides having inherent viscosities up to 1.8 dL/g were synthesized either by the direct polycondensation of 2,2′‐bibenzoic acid with various aromatic diamines or by the low temperature solution polycondensation of 2,2′‐bibenzoyl chloride with aromatic diamines. All the aromatic polyamides were amorphous and soluble in a variety of organic solvents including N,N‐dimethylacetamide (DMAc), N‐methyl‐2‐pyrrolidone, dimethyl sulfoxide, m‐cresol, and pyridine. Transparent and flexible films of these polymers could be cast from the DMAc solutions. These aromatic polymides had glass transition temperatures in the range of 226‐306deg;C and began to lose weight around 350°C in air.

Thermotropic liquid crystals of polyesters having a mesogenic p,p'-bibenzoate unit. 1. Smectic A mesophase properties of polyesters composed of p,p'-bibenzoic acid and alkylene glycols

ADVERTISEMENT RETURN TO ISSUEPREVArticleThermotropic liquid crystals of polyesters having a mesogenic p,p'-bibenzoate unit. 1. Smectic A mesophase properties of polyesters composed of p,p'-bibenzoic acid and alkylene glycolsJunji Watanabe and Manabu HayashiCite this: Macromolecules 1988, 21, 1, 278–280Publication Date (Print):January 1, 1988Publication History Published online1 May 2002Published inissue 1 January 1988https://doi.org/10.1021/ma00179a059RIGHTS & PERMISSIONSArticle Views344Altmetric-Citations101LEARN ABOUT THESE METRICSArticle Views are the COUNTER-compliant sum of full text article downloads since November 2008 (both PDF and HTML) across all institutions and individuals. These metrics are regularly updated to reflect usage leading up to the last few days.Citations are the number of other articles citing this article, calculated by Crossref and updated daily. Find more information about Crossref citation counts.The Altmetric Attention Score is a quantitative measure of the attention that a research article has received online. Clicking on the donut icon will load a page at altmetric.com with additional details about the score and the social media presence for the given article. Find more information on the Altmetric Attention Score and how the score is calculated. Share Add toView InAdd Full Text with ReferenceAdd Description ExportRISCitationCitation and abstractCitation and referencesMore Options Share onFacebookTwitterWechatLinked InReddit PDF (1 MB) Get e-Alerts Get e-Alerts

Thermotropic homopolyesters: 5. Investigation of the smectic phase of polyesters based on p, p′-bibenzoic acid

We report a study of the mesophases of the homologous series of polymers prepared from p, p′-bibenzoic acid and the tetra-, hexa-, octa-, and decamethylene glycols. These polymers are designated BB n, where n is the number of methylene units in the diol. The BB4 and BB6 polymers form a thermotropic smectic phase which was independently identified as S A by mutual miscibility studies with a known low molecular weight mesogen, TBBA, and by X-ray diffraction studies of oriented samples. The enthalpy change for the smectic-isotropic transition is only 1.4 Kcal mol −1 a value consistent with a smectic phase of low order. The smectic layer spacing is shorter than the fully extended length of the repeating unit for both BB4 and BB6. Low molecular weight samples of BB6 exhibit three crystal modifications. The two higher temperature forms have the same c-axis spacing as the smectic layer spacing, 18.7 Å, while the polymorph stable at room temperature has a fibre repeat of 32 Å, indicating a still smaller distance per repeating unit, 16 Å. All of these values are smaller than the 20 Å length of the fully extended repeating unit. Shearing the smectic hase of BB6 polymers having η inh < 0.45 dL/g produces a highly oriented sample in which the repeating units are perpendicular to the direction of flow. Shear of the smectic phases of polymers having higher intrinsic viscosities breaks up the smectic structure, and leads to less perfect orientation of the molecules parallel to the shear direction.