Synthesis and phase transition of liquid crystalline homopoly(ester–imide) and copoly(ester–imide)s with different lengths of methylene spacers

Kim, S.O; Jeon, Byoung Ho; Chung, In Jae

doi:10.1016/s0032-3861(00)00540-1

Cited by 4 publications

(14 citation statements)

References 42 publications

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“…There are various approaches for increasing of the solubility and processability of polyimides without sacrificing their high thermal sta-bility1 for example, attachment of bulky substituents or pendent groups to the rigid polyimide backbone and/or introduction of flexible bridge groups like ether, ester, sulfone, in the polymer chain. The net result is often a lowering of the processing temperature and improvement in the flow property at the expense of the thermal stability [11]. Another approach involves the synthesis of copolyimides such as poly(ester-imide)s (PEI)s and poly(amide-imide)s (PAI)s by incorporating amide or ester functionality at regular intervals in the polyimide chain.…”

Section: S Mallakpour and S Meratianmentioning

confidence: 99%

Synthesis and Characterization of Organosoluble Optically Active Poly(ester-imide)s Derived from Trimellitic Anhydride, L-Methionine and Bisphenols

Mallakpour

Meratian

2007

High Performance Polymers

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The reaction of thionyl chloride in pyridine as a condensing agent was used for the direct polycondensation of N-trimellitylimido-L-methionine (4) with various aromatic diols such as bisphenol A (5a), phenolphthalein (5b), 1,5-naphthalendiol (5c), 2,6-dihydroxytoluene (5d), hydroquinone (5e), biphenyl-2,2'-diol (5f), 1,4-dihydroxyanthraquinone (5g). This reaction leads to the formation of novel optically active poly(ester-imide)s (PEI)s. The resulting PEIs were obtained in good yields and exhibited low to moderate inherent viscosities ranging from 0.15 to 0.40 dL g-1. All of the PEIs showed good solubility and readily dissolved in solvents such as N-methyl-2-pyrrolidinone (NMP), N,N-dimethylacetamide (DMAc), N,N-dimethylformamide (DMF), pyridine and tetrahydrofuran. Thermogravimetric analysis showed that PEI 6b was stable, with 10% weight loss recorded above 370 oC in nitrogen. All of the above polymers were characterized by FTIR, specific rotation, and representative PEIs were also characterized by 1 H NMR, elemental analysis, and thermogravimetric analysis. The structural characterization and physical properties of these new optically active PEIs are reported.

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Section: S Mallakpour and S Meratianmentioning

confidence: 99%

Synthesis and Characterization of Organosoluble Optically Active Poly(ester-imide)s Derived from Trimellitic Anhydride, L-Methionine and Bisphenols

Mallakpour

Meratian

2007

High Performance Polymers

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“…They showed that the Avrami exponent value for crystallization in smectic phase is two, whereas the value in isotropic phase is three, and the wide-angle X-ray diffraction (WAXD) patterns of the crystal formed in monotropic smectic phase and isotropic phase were different for the poly(ester−imide)s with odd number of methylene spacers. In our previous articles, we synthesized liquid crystalline poly(ester−imide)s and characterized their monotropic phase transition behaviors with rheological methods. , The Avrami exponent value for crystallization was four in both isotropic and nematic phases, and the WAXD patterns of the crystallized samples are the same regardless of the precursor phase. The crystal formed from nematic phase showed the higher melting temperature than that from isotropic melt.…”

Section: Introductionmentioning

confidence: 99%

“…The crystal formed from nematic phase showed the higher melting temperature than that from isotropic melt. From the previous crystallization studies on monotropic liquid crystalline polymers, the most significant conclusion is that the crystallization accelerates in the presence of liquid crystalline ordering. ,,,6a,c,− However, the mechanism for the acceleration of crystallization has been unknown.…”

Section: Introductionmentioning

confidence: 99%

Phase Behavior, Crystallization Kinetics, and Morphology of Monotropic Liquid Crystalline Poly(ester−imide)s with a Decamethylene Spacer

et al. 2001

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The phase transition, crystallization kinetics, and morphology of monotropic liquid crystalline poly(ester-imide)s are investigated by synchrotron X-ray diffraction, differential scanning calorimetry (DSC), polarized light microscopy (PLM), and transmission electron microscopy (TEM). Synchrotron X-ray diffraction and DSC results show that the poly(ester-imide) with methyl side pendant group (10M) exhibits monotropic nematic and smectic A phases upon cooling from the isotropic melt, followed by a crystalline phase (crystal E structure). The results of isothermal crystallization kinetics show that the crystallization rate is faster in the smectic phase than in the nematic phase and the slowest in the isotropic phase. It is found that the crystallization in the nematic phase leads to lamellar decorated disclination structures upon TEM observation, indicating that the enhancement of nucleation dominates the acceleration of crystallization. Poly(ester-imide) without side pendant group (10H) forms only a crystalline phase upon cooling. However, the air-quenched sample shows a threadlike texture. TEM observation further reveals the trace of nematic disclination structures, confirming that the crystallization proceeds through nematic phase. In contrast, the sample, cooled with a slow cooling rate of 5 °C/min, exhibits the spherulite structure. The morphological variation of the poly(ester-imide) is discussed on the basis of competition between primary nucleation and crystal growth.

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“…Study on phase transitions in main chain liquid crystalline polymers is a very interesting subject, and enormous efforts on understanding these transitions have been made. − As the majority of liquid crystalline polymers are polyesters or copolyesters based on 4-hydroxybenzoic acid (HBA), systematic investigation on the phase behavior of liquid crystalline polyimides is still lacking due to the very rare availability of liquid crystalline polyimide samples. Pardey et al − studied the liquid crystal transition, ordered structure, and crystallization kinetics in a series of thermotropic poly(ester imide)s synthesized from N -[4-(chloroformyl)phenyl]-4-(chloroformyl) phthalimide and the respective diols with the number of methylene groups ( n ) varying from 4 to 12.…”

Section: Introductionmentioning

confidence: 99%

“…Pardey et al − studied the liquid crystal transition, ordered structure, and crystallization kinetics in a series of thermotropic poly(ester imide)s synthesized from N -[4-(chloroformyl)phenyl]-4-(chloroformyl) phthalimide and the respective diols with the number of methylene groups ( n ) varying from 4 to 12. Kim et al − synthesized and characterized a series of liquid crystalline poly(ester−imide)s derived from N -(ω-carboxyalkylene) trimellitic imides. However, most of these poly(ester−imide)s are monotropic, and their mesophase could only be achieved during cooling.…”

Section: Introductionmentioning

confidence: 99%

Phase Transition and Transition Kinetics of a Thermotropic Poly(amide−imide) Derived from 70 Pyromellitic Dianhydride, 30 Terephthaloyl Chloride, and 1,3-Bis[4-(4‘-aminophenoxy)cumyl]benzene

Liu¹,

Chung²,

Geng³

et al. 2001

Macromolecules

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The phase transition and transition kinetics of a liquid crystalline copoly(amide−imide) (PAI37), which was synthesized from 70 mol % pyromellitic dianhydride, 30 mol % terephthaloyl chloride, and 1,3-bis[4-(4‘-aminophenoxy)cumyl]benzene, was characterized by differential scanning calorimetry, polarized light microscopy, X-ray diffraction, and rheology. PAI37 exhibits a glass transition temperature at 182 °C followed by multiple phase transitions. The crystalline phase starts to melt at ∼220 °C and forms smectic C (SC) phase. The SC phase transforms into smectic A (SA) phase when the temperature is above 237 °C. The SC to SA transition spans a broad temperature range in which the SA phase vanishes and forms isotropic melt. The WAXD fiber pattern of PAI37 pulled from the anisotropic melt revealed an anomalous chain orientation, which was characterized by its layer normal perpendicular to the fiber direction. The transition kinetics for the mesophase and crystalline phase formation was also studied.

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Synthesis and phase transition of liquid crystalline homopoly(ester–imide) and copoly(ester–imide)s with different lengths of methylene spacers

Cited by 4 publications

References 42 publications

Synthesis and Characterization of Organosoluble Optically Active Poly(ester-imide)s Derived from Trimellitic Anhydride, L-Methionine and Bisphenols

Synthesis and Characterization of Organosoluble Optically Active Poly(ester-imide)s Derived from Trimellitic Anhydride, L-Methionine and Bisphenols

Phase Behavior, Crystallization Kinetics, and Morphology of Monotropic Liquid Crystalline Poly(ester−imide)s with a Decamethylene Spacer

Phase Transition and Transition Kinetics of a Thermotropic Poly(amide−imide) Derived from 70 Pyromellitic Dianhydride, 30 Terephthaloyl Chloride, and 1,3-Bis[4-(4‘-aminophenoxy)cumyl]benzene

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