Synthesis and Thermal Analysis of Fourteen Homologous Mesogenic Monoesters of Biphenyl-4,4'-dicarboxylic Acid

Cohen, Sanford N.; Diuguid, C. A. Risinger; Poirier, Jacques C.; Swadesh, Joel K.

doi:10.1080/00268948108082152

Cited by 10 publications

(10 citation statements)

References 8 publications

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“…Schlieren textures are observed for smectic A, C and F However, miscibility studies supported by X-ray investigations have identified the second smectic phase as smectic F and the high temperature phase as smectic C, consistent with Ref. 3. Clear differences between both phases are observable in a Goniometer plot of the substance with n = 11 at temperatures of 210°C and 150°C (see Fig.…”

Section: Properties Of Biphenyl Dicarboxylic Acidsupporting

confidence: 78%

Phase Structure and Polymorphism of n-Alkyl Monoesters of Biphenyl-4,4′-dicarboxylic Acid

Swadesh¹,

Fischer²

1996

Molecular Crystals and Liquid Crystals Science and Technology.

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The phase structure of the n-alkyl monoesters of biphenyl-4,4-dicarboxylic acid has been investigated using optical microscopy and X-ray diffraction techniques. A polymorphism N, S,, S, and crystal B has been found which is understandable because of the essentially 2-d correlated smectic F phase with only a small interlayer correlation and the extensive 3-d correlation of the smectic B phase. The formation of dimers via H-bridges and an intercalation of the dimers which is active within the first 4 to 5 CH, groups of the tail groups of the dimers in both ends have been proven by X-ray diffraction.

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Section: Properties Of Biphenyl Dicarboxylic Acidsupporting

confidence: 78%

Phase Structure and Polymorphism of n-Alkyl Monoesters of Biphenyl-4,4′-dicarboxylic Acid

Swadesh¹,

Fischer²

1996

Molecular Crystals and Liquid Crystals Science and Technology.

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“…[5][6][7][8][9][10][11][12][13][14][15] In contrast, low molecular weight dialkyl 4,4′-bibenzoates do not exhibit liquid crystallinity. 16 Several papers describe the application of BB to improve the properties of PET. 3,4,[17][18][19][20][21][22] Knopka reported that the modulus of a fiber spun from a 50:50 copolymer, poly(ethylene terephthalate-co-4,4′-bibenzoate) (PETBB50), was as high as 191 g/den (∼20 GPa).…”

Section: Introductionmentioning

confidence: 99%

“…16 Several papers describe the application of BB to improve the properties of PET. 3,4,[17][18][19][20][21][22] Knopka reported that the modulus of a fiber spun from a 50:50 copolymer, poly(ethylene terephthalate-co-4,4′-bibenzoate) (PETBB50), was as high as 191 g/den (∼20 GPa). 4 Modification of PET by BB resulted in improved T g , strength, modulus, and gas barrier properties.…”

Section: Introductionmentioning

confidence: 99%

“…The 4,4‘-biphenyl moiety has been incorporated as a rigid structure unit both as diol and diacid in wholly aromatic as well as in semiflexible polyesters. , Homopolymers prepared by condensation of 4,4‘-bibenzoic acid (BB) and α,ω-alkanediols, HO(CH 2 ) n OH, in which the number of repeating methylene groups ranges from 4 to 10, are all smectic. − In contrast, low molecular weight dialkyl 4,4‘-bibenzoates do not exhibit liquid crystallinity …”

Section: Introductionmentioning

confidence: 99%

“…Several papers describe the application of BB to improve the properties of PET. ,,− Knopka reported that the modulus of a fiber spun from a 50:50 copolymer, poly(ethylene terephthalate- co -4,4‘-bibenzoate) (PETBB50), was as high as 191 g/den (∼20 GPa) .…”

Section: Introductionmentioning

confidence: 99%

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Fiber Spinning, Structure, and Properties of Poly(ethylene terephthalate-co-4,4‘-bibenzoate) Copolyesters

Hibbs

Collard

et al. 2002

Macromolecules

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Thermal, rheological, and fiber spinning behavior of poly(ethylene terephthalate-co-4,4‘-bibenzoate) random copolymers containing 5−65 mol % bibenzoate (BB) units have been studied. Copolymer randomness was determined by 13C solution NMR. Copolymers with >40 mol % BB units spin like thermotropic liquid crystals and have mechanical properties approaching those of liquid crystals; however, no evidence of liquid crystallinity was observed in these fibers based on thermal, optical, and rheological studies. Thus, we believe these polymers are frustrated liquid crystalline polymers. The α-relaxation attributed to the glass transition temperature is completely suppressed in the fully drawn and heat-treated PETBB55 fibers. Structure development during fiber spinning as well as fiber mechanical properties have been studied. Fibers containing more than 40 mol % bibenzoate show the development of a new crystal structure and exhibit much higher tensile modulus than the copolymers containing a lower bibenzoate percentage. Copolymers containing more than 40 mol % bibenzoate also exhibit high melt relaxation times compared to the lower bibenzoate copolymers.

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Effect of methyl groups on the thermal properties of polyesters from methyl substituted 1,4‐butanediols and 4,4′‐biphenyldicarboxylic acid

Loman¹,

Does²,

Bantjes³

et al. 1995

J. Polym. Sci. A Polym. Chem.

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SYNOPSISResults are reported on the effect of lateral methyl groups on the thermal properties of a series of polyesters prepared from diethyl 4,4'-biphenyldicarboxylate and various methyl substituted 1,4-butanediols. The diols were 1,4-butanediol; 2-methyl-1,4-butanediok 2,2-dimethyl-1,4-butanediol; 2,3-dimethyl-1,4-butanediol; 2,2,3-trimethyl-1,4-butanediol; and 2,2,3,3-tetramethyl-1,4-butanediol. Apart from the tetramethyl derivative, the transition temperatures of the methyl substituted polyesters were lower with respect to the unsubstituted polyester. On the basis of polarized photomicrographs, a smectic A mesophase was found for the unsubstituted polyester, whereas a nematic mesophase was observed for the 2-methyl substituted polyester. The 2,2-dimethyl, 2,3-dimethyl, and the 2,2,3-trimethyl substituted polyesters showed no liquid crystalline behavior. The 2,2,3,3-tetramethyl derivative displayed a birefringent melt phase although the DSC measurements were not unambiguous. A copolyester based on diethyl 4,4'-biphenyldicarboxylate, 1,4-butanediol, and 2,2,3,3-tetramethyl-1,4-butanediol showed a broad nematic mesophase. Further evidence for the nematic mesophase of this copolyester and the 2-methyl substituted polyester was provided by dynamic rheological experiments. Based on thermogravimetric analysis, it was concluded that the thermal stability was affected only when four methyl side groups were present in the spacer. 0 1995 John Wiley & Sons, Inc.

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Synthesis and Thermal Analysis of Fourteen Homologous Mesogenic Monoesters of Biphenyl-4,4'-dicarboxylic Acid

Cited by 10 publications

References 8 publications

Phase Structure and Polymorphism of n-Alkyl Monoesters of Biphenyl-4,4′-dicarboxylic Acid

Phase Structure and Polymorphism of n-Alkyl Monoesters of Biphenyl-4,4′-dicarboxylic Acid

Fiber Spinning, Structure, and Properties of Poly(ethylene terephthalate-co-4,4‘-bibenzoate) Copolyesters

Effect of methyl groups on the thermal properties of polyesters from methyl substituted 1,4‐butanediols and 4,4′‐biphenyldicarboxylic acid

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