Synthesis and comparative physicochemical investigation of partly aromatic cardo copolyesters

Copolyesters were synthesized through the condensation of 0.0025 mol of 1,1′‐bis(3‐methyl‐4‐hydroxyphenyl)cyclohexane, 0.0025 mol of ethylene glycol/propylene glycol/1,4‐butanediol/1,6‐hexane diol, and 0.005 mol of terephthaloyl chloride with water/chloroform (4:1 v/v) as an interphase, 0.0125 mol of sodium hydroxide as an acid acceptor, and 50 mg of cetyl trimethyl ammonium bromide as an emulsifier. The reaction time and temperature were 2 h and 0°C, respectively. The yields of the copolyesters were 81–96%. The structures of the copolyesters were supported by Fourier transform infrared and ¹H‐NMR spectral data and were characterized with the solution viscosity and density by a floatation method (1.1011–1.2697 g/cm³). Both the intrinsic viscosity and density of the copolyesters decreased with the nature and alkyl chain length of the diol. The copolyesters possessed fairly good hydrolytic stability against water and 10% solutions of acids, alkalis, and salts at room temperature. The copolyesters possessed moderate‐to‐good tensile strength (11–37.5 MPa), good‐to‐excellent electric strength (19–45.6 kV/mm), excellent volume resistivity (3.8 × 10¹⁵ to 2.56 × 10¹⁷ Ω cm), and high glass‐transition temperatures (148–195°C) and were thermally stable up to about 408–427°C in a nitrogen atmosphere; they followed single‐step degradation kinetics involving 38–58% weight losses and 34–59% residues. The copolyesters followed 2.6–2.9‐order degradation kinetics. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2007     

Thermotropic liquid crystalline copolyesters. I. Synthesis and thermal characterization of the copolyesters of terephthaloyl chloride,hydroquinone, and 1,4-butane diol

A new series of random thermotropic liquid crystalline polyesters (LCPs) was synthesized from terephthaloyl chloride, hydroquinone, and 1,4-butane diol. The copolyester composition was varied by changing the relative mole ratio of hydroquinone and 1, 4-butane diol in the feed. All the copolyesters displayed thermotropic liquid crystallinity at relatively low temperatures. Liquid crystalline behavior of the copolyesters has been characterized by polarizing light microscopy and by differential scanning calorimetry (DSC). The effect of co-polyester composition on the temperature and thermodynamic parameters related to liquid crystalline transition is discussed. © 1993 John Wiley & Sons, Inc.     

Aliphatic-aromatic copolyesters containing phosphorous cyclic bulky groups

A series of phosphorus-containing copolyesters was prepared by polycondensation of 2-(6-oxido-6H-dibenz<c,e><1,2>oxaphosphorin-6-yl)-1,4-naphthalene diol, 1, or of an equimolecular amount of 1 and different aliphatic diols 2, such as ethylene glycol, 1,3-propanediol, 1,4-butanediol, 1,6-hexanediol and 1,12-dodecanediol, with an aromatic diacid chloride containing two preformed ester groups 3, namely terephthaloyl-bis-(4-oxybenzoyl-chloride). The copolyesters exhibited good thermal stability having the decomposition temperature above 375 °C. The glass transition temperature was in the range of 96-146 °C. The polymers exhibited thermotropic liquid crystalline behavior, as was observed with polarized optical microscopy. DSC and X-ray experiments were also found in concordance with mesophase formation.     

Preparation and characterizations of thermotropic copolyesters of p-hydroxybenzoic acid,sebacic acid,and hydroquinone

A series of copolyesters of p-hydroxybenzoic acid (HBA), sebacic acid and hydroquinone were prepared by melt polycondensation of p-acetoxybenzoic acid, sebacic acid and p-phenylene diacetate. The copolyesters were characterized by IR, NMR, DSC, polarized microscopy, and X-ray diffraction. It was found that the copolyesters exhibited liquid crystallinity when the HBA content was 25–67 mol %. The copolyesters with an HBA content of 25–43 mol % showed a nematic phase and a biphasic range, and the isotropization temperature increased as the HBA content increased. The copolyesters with an HBA content of 54–67 mol % showed a nematic phase up to above 400°C. The liquid crystalline order increased as the HBA content increased due to the increased of the average length of the rigid moieties. © 1995 John Wiley & Sons, Inc.     

Structure of liquid crystalline copolyesters from two acetoxybenzoic acids and polyethylene terephthalate

The molecular and supermolecular structures of thermotropic liquid crystalline copolyesters from p-acetoxybenzoic acid (B), polyethylene terephthalate (E), and m-acetoxybenzoic acid (M) were studied by Fourier transform infrared spectrometer, 200-MHz ¹H-nuclear magnetic resonance (NMR), and wide-angle X-ray diffraction methods. The assignments of resonance peaks in NMR spectra are given and the effect of B/E/M molar ratio on the NMR spectra and number-average degree of polymerization of the copolyesters are discussed. The equatorial, meridional, and azimuthal scans, and their dependency on monomer mole ratio for the copolymers, are elaborated. The persistence length and orientation of the copolymer ribbons were found to increase with an increase in p-oxybenzoate unit content from 60 to 75 mol % at a fixed m-oxybenzoate unit content of 5 mol %. © 1999 John Wiley & Sons, Inc. J Appl Polym Sci 73: 2921–2925, 1999     

Synthesis and properties of new aromatic copolyesters containing phosphorous cyclic bulky groups

A series of phosphorus‐containing copolyesters was prepared by polycondensation of 2‐(6‐oxido‐6H‐dibenz<c,e><1,2>oxaphosphorin‐6‐yl)‐1,4‐naphthalene diol, 1 , or of an equimolecular amount of 1 and different bisphenols 2 , such as 4,4′‐isopropylidenediphenol, 4,4′‐(hexafluoroisopropylidene)diphenol and 2,7‐dihydroxynaphthalene, with an aromatic diacid chloride containing two preformed ester groups 3 , namely, terephthaloyl‐bis‐(4‐oxybenzoyl‐chloride). The copolyesters exhibited good thermal stability having the temperature of 5% weight loss above 380°C and char yield at 700°C in the range of 20–31.2%. The glass transition temperature was in the range of 136–147°C. The polymers exhibited thermotropic liquid crystalline behavior, as was observed with polarized optical microscopy, differential scanning calorimetry, and X‐ray experiments. POLYM. ENG. SCI., 2010. © 2010 Society of Plastics Engineers     

Sequence distribution and thermal properties of poly(butylene naphthalate terephthalate)

Poly(butylene naphthalate terephthalate) (PBNT) copolyesters were synthesized from bis(4-hydroxybutyl) terephthalate (BHBT) and bis(4-hydroxybutyl) naphthalate (BHBN) as starting materials. BHBT and BHBN were either homopolymerized or copolymerized at 260∼270 °C in the presence of titanium tetrabutoxide (TBT) as a catalyst to provide PBNT with various compositions. The copolyesters were characterized using inherent viscosity, X-ray, d.s.c., t.g.a. and ¹H NMR. The composition and sequence distribution of the copolyesters was determined from ¹H NMR spectra. The copolyesters exhibited a degree of randomness of about 1, indicating that the reactivity of BHBT and BHBN was almost the same. X-ray and d.s.c. showed PBNT copolyesters to be crystalline polymers. T.g.a. kinetics showed PBNT copolyesters to exhibit higher degradation activation energy, that is, better thermal stability, than PBTs.     

Synthesis of cyanoethyl konjac glucomannan and its liquid crystalline behavior in an ionic liquid

Cyanoethyl konjac glucomannan (CKGM) products with various degree of substitution (DS) were synthesized, and their chemical structure was characterized by infrared spectroscopy and ¹H and ¹³C NMR spectroscopy. Direct evidence of the formation of liquid crystalline phase of cyanoethyl KGM (DS = 2.10) solution in 1-allyl-3-methylimidazolium chloride (AMIMCl), a room temperature ionic liquid, was confirmed by using polarized optical microscopy (POM). The mesophase and anisotropic phase of cyanoethyl KGM solutions and the phase transition boundaries were investigated by steady shear and dynamic sweep measurements. The crystalline state of the cyanoethyl KGM powder and solution were studied by wide X-ray diffraction.     

Novel tailor-made diols for polyurethane coatings using a combination of controlled radical polymerization,ring opening polymerization,and click chemistry

Novel dihydroxy functional 3-arm star polymers were synthesized using a combination of atom transfer radical polymerization, ring opening polymerization, and click chemistry. The diols were characterized using gel permeation chromatography, Fourier transform infrared spectroscopy, and ¹H NMR spectroscopy. The diols were incorporated into polyurethane coatings, which were characterized using differential scanning calorimetry, thermogravimetric analysis, pendulum hardness, water contact angle, and methyl ethyl ketone double rubs. The coatings showed an increase in the water contact angle values as the percentage of the polystyrene-based diol was increased. Similarly, the coatings with the poly(tert-butyl acrylate)-based diols showed a decrease in the glass transition temperature values with an increase in the diol content. It is expected that the use of controlled radical polymerization would allow for the synthesis of novel tailor-made functional polymers to achieve tunable coatings properties.     

Syntheses and characterization of poly(butylene terephthalate) copolyesters modified with p‐acetoxybenzoic acid

Poly(butylene terephthalate) (PBT) copolyesters modified with seven compositions of p‐acetoxybenzoic acid (PABA) ranging from 10 to 70 mol % were prepared. The X‐ray diffraction patterns, the polarizing microscopy behaviors, and thermal analysis showed that the modified PBT contained more PABA homopolymer units (PABA–PABA) than PBT–PABA units in the copolyesters. On increasing PABA mole percenage, PBT crystallinity decreased and thermal stability increased. It was found that although the PBT copolyesters did not exhibit a clear liquid crystalline texture like the copolyester of poly(ethylene terephthalate) modified with PABA did, the PBT copolyester containing 70 mol % of PABA exhibited the typical shear thinning behavior of a liquid crystalline polymer. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 80: 1085–1095, 2001     

Aromatic liquid crystalline copolyesters with low Tm and high Tg: Synthesis,characterization, and properties

In this study, a series of aromatic copolyesters P‐BPAx with lower melting temperature and higher glass transition temperature derived from hydroxybenzoic acid (HBA), 6‐hydroxy‐2‐naphthoic acid (HNA), bisphenol A (BPA) and terephthalic acid (TA) were synthesized via melt polymerization. The copolyesters were characterized by FTIR, solid state ¹³C NMR, DSC, TGA, polarized optical microscopy, X‐ray diffraction, and rheometry measurements. With addition of BPA, the resulting copolyester's melting temperature decreased from 260 to 221°C and its glass transition temperature increased from 70 to 135°C, compared with the parent copolyester P‐HBA70 (HBA/HNA copolymer). With exception of copolyester P‐BPA5.0 (225–280°C), the copolyesters could maintain liquid crystalline behavior in a broad temperature range from 230°C to higher than 410°C. The ability to form nematic liquid crystalline phase disappeared when BPA concentration became higher than 15 mol %. X‐ray diffraction analysis showed crystallinity decreased as the BPA content increased. A slightly distorted O" and a substantially distorted O′ orthorhombic phase was observed for P‐BPA2.5. Upon annealing at 220°C, the O" phase disappeared and the O′ phase became stronger gradually. Rheology study data showed the ability to process the copolyesters improved in those compositions containing <2.5 mol % BPA. Continuing to increase concentrations of BPA, they became intractable. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 40487.     

Synthesis and characterization of cholesteric thermotropic liquid crystalline polyesters

Cholesteric liquid crystalline polyesters were successfully synthesized from isosorbide, methyl hydroquinone, and isophthaloyl chloride. Homo/copolyesters were synthesized by the solution polycondensation method, for which a mild organic base such as pyridine was employed. Inherent viscosities of polyesters P‐3–P‐5 were in the range of 0.31–0.39 dL/g at 25°C in chloroform, and polyesters P‐1 and P‐2 were insoluble in chloroform. Homo/copolyesters based on isosorbide, methyl hydroquinone, and isophthalic acid had thermal stability at more than 300°C on the basis of 10% weight loss. The thermotropic liquid crystalline properties were examined by differential scanning calorimetry and polarizing optical microscopy. Wide‐angle X‐ray diffraction study demonstrated that polyesters P‐1, P‐2, and P‐3 were semicrystalline, whereas the degree of crystallinity of polyesters P‐4 and P‐5 was less than 5%. Copolyester P‐4 showed formation of a yellow iridescent streak at 209°C on heating and development of a Grandjean texture at 270°C on heating. These are typical textures of the cholesteric liquid crystalline phase. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 103: 1232–1237, 2007     

Polybutadiene/polyhedral oligomeric silsesquioxane nanohybrid: investigation of various reactants in polyesterification reaction

Nano‐sized polyhedral oligomeric silsesquioxane (POSS) diol or ethylene glycol (EG) as diol monomer was incorporated into hydroxyl‐terminated polybutadiene (HTPBD) chain in the presence of fumaryl or thionyl chloride as extenders. Using these polyesterification reactions, two fumarate‐based polyesters and two polyester sulfites were synthesized. Each couple of polyesters and polyester sulfites includes a linear (diol:EG) and a nanohybrid macromer (diol:POSS). Full structural characterization was performed using Fourier transform infrared, ¹H NMR and ¹³C NMR spectroscopies. Gel permeation chromatography was undertaken to study polyesterification mechanisms by deconvolution of the obtained traces. Finally, differential scanning calorimetry, thermogravimetric analysis and cell culture were performed to evaluate the structure–property relationship for the synthesized macromers in comparison with unreacted HTPBD. © 2016 Society of Chemical Industry     

Fast crystallization of liquid crystalline copolyesters based on poly(ethylene terephthalate)

Crystallization of a series of liquid crystalline copolyesters prepared from p‐hydroxybenzoic acid (HBA), hydroquinone (HQ), terephthalic acid (TA), and poly(ethylene terephthalate) (PET) was investigated by using differential scanning calorimetry (DSC). It was found that these copolyesters are more crystalline than copolyesters prepared from PET and HBA. Insertion of HQ–TA disrupts longer rigid‐rod sequences formed by HBA and thus enhances molecular motion and increases the crystallization rate. The effects of additives on the crystallization of the copolyesters were also studied. Sodium benzoate (SB) and sodium acetate (SA) increase the crystallization rate of the copolyesters at low temperature, but not at high temperature. It is most likely that liquid crystalline copolyesters do not need nucleating agents, and small aggregates of local‐oriented rodlike segments in nematic phase could act as primary nuclei. Chain scission of the copolyesters caused by the reaction with the nucleating agents was proved by the determination of intrinsic viscosity and by the IR spectra. Diphenylketone (DPK) was shown to effectively promote molecular motion of chains, leading to an increase in the crystallization rate at low temperature, but it decreased the crystallization rate at high temperature. © 2000 John Wiley & Sons, Inc. J Appl Polym Sci 79: 497–503, 2001     

Novel amine preaccelerators for polyester resins

The reactions between N,N‐dimethyl‐p‐phenylenediamine and ethylene or propylene oxide were carried out to obtain 3‐[p‐(N,N‐dimethylamino)phenyl]‐3‐azapentane‐1,5‐diol and 4‐[p‐(N,N‐dimethylamino)phenyl]‐4‐azaheptane‐2,6‐diol, respectively. The structures of the products were determined using elemental analysis, ¹H‐NMR and IR spectroscopy techniques. The diols were incorporated into unsaturated polyester resins. The time of gelation and stability of the resins was observed. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 89: 2973–2976, 2003     

Complexation of Titanium Alkoxides with Cis-2-butene-1,4-diol and Hydrolysis of Their Products

Reaction of Ti(OEt)₄ and Ti(OBu ⁿ )₄ with cis-2-butene-1,4-diol (B.diol-2H) in 1:1 molar ratio was studied at room temperature using the sol-gel process. ¹³C{¹H}- and ¹H-NMR data showed that all the B.diol-2H completely reacted with both titanium alkoxides. Each of the products was hydrolyzed by water. The new hydrolyzed products were characterized by ¹³C- and ¹H-NMR spectroscopy and Karl–Fischer Titration. Thermogravimetric and differential thermal analyses (TGA-DTA) of the hydrolyzed-products were also studied.     

PET／60PABA 热致型液晶共聚酯的合成与表征

将对羟基苯甲酸（PHB）的乙酰化产物对乙酰氧基苯甲酸（PABA）引入聚酯（PET）分子主链结构中,成功制备出共聚酯 PET /60PABA,研究了聚合温度和催化剂浓度对共聚酯合成的影响。通过差示扫描量热（DSC）、X 射线衍射（XRD）、超导核磁共振（NMR）、凝胶渗透色谱（GPC）、偏光显微镜（POM）和毛细管流变仪等手段对共聚酯的分子结构与液晶形态进行表征,结果表明,共聚酯 PET /60PABA 几乎为完全无规共聚,熔融状态下具有向列型热致液晶聚合物的典型特征。     

Synthesis of copolyesters having tertiary amine groups or zwitterion moieties in the main chain

Copolyesters having tertiary amine groups or zwitterion moieties in the main chain were prepared from terephthaloyl chloride (TPC) and mixtures of bisphenol A and aliphatic diols such as N-ethyldiethanolamine (EDA), N,N-bis(2-hydroxyethyl)-2-aminoethanesulfonic acid (BES) and N,N-bis(2-hydroxyethyl)glycine (BHG) by a liquid/solid biphase polycondensation in trimethyl phosphate (TMP) as well as a water phase/organic phase interfacial polycondensation. The composition of copolymers obtained by the biphase polycondensation is close to that of the feeds. The nucleophilicity of hydroxyl groups of these aliphatic diols is increased in TMP and the solvent TMP participates in the reaction. In the water phase/organic phase interfacial polycondensation, the copolyester (P1) from EDA has a higher aliphatic diol residue content than P2 and P3 from BES and BHG, because the self-nucleophilic catalysis of the tertiary amine groups of the resulting polymer occurs in the organic phase. The copolyesters (P2 and P3) having pendant hydrophilic groups contain very few aliphatic diol residues because the self-nucleophilic catalysis of the tertiary amine groups takes place in the water phase and the extensive hydrolysis of the intermediate occurs, which results from TPC with the tertiary amine groups during the reaction.     

Sequential distribution of main chain phosphorus-containing copolyesters characterized by 1H NMR

A series of main chain phosphorus-containing copolyesters were synthesized by polycondensation of terephthalic acid (TPA), ethylene glycol (EG) and phenyl phosphonic acid (PPA). Chemical structures of these main chain phosphorus-containing copolyesters were characterized by ¹H NMR. Experimental results show that the resonance intensity of PPA aromatic protons increases with increase of the phosphorus content. The chemical shifts of the ethylene protons in the ethylene glycol units vary with different sequences. The resonance chemical shift of the ethylene protons of the T-E-T unit is higher than those of P-E-T (T-E-P) and P-E-P units. The monomer molar fraction, sequential distribution and degree of randomness of the phosphorus-containing copolyesters were determined through analyses of the ethylene protons in the ethylene glycol units. The molar fractions of the PPA comonomer determined by ¹H NMR analyses are close to the values determined by a UV method. The degree of randomness for the copolyesters was found to be in the range 0·66–0·83. © 1998 SCI.     

New polymer syntheses VIII. Synthesis,characterization and morphology of new unsaturated copolyesters based on dibenzylidenecycloalkanones

A new interesting class of linear, unsaturated copolyesters based on dibenzylidenecycloalkanones has been synthesized by interfacial polycondensation of isophthaloyl chloride or sebacoyl chloride with 2,5-bis(p-hydroxybenzylidene) cyclopentanone I, 2,6-bis(p-hydroxybenzylidene) cyclohexanone II, 2,6-divanillylidenecyclohexanone III or 2,7-bis(p-hydroxybenzylidene)cycloheptanone IV at ambient temperature. The resulting copolyesters were characterized by elemental analyses, IR spectroscopy, and solubility. Additionally, inherent viscosities of copolyesters in the range 0·53–0·98dlg⁻¹ were determined. The thermal properties of the polymers were evaluated by TGA and DSC measurements and correlated with their structural units. The crystallinity of some copolyesters was examined by X-ray analysis. In addition, the electrical properties of the copolyesters were tested and the morphology of selected examples of the copolyesters was examined by scanning electron microscopy. © 1998 Society of Chemical Industry