Thermotropic homopolyesters—VI. A study of polymers based on 4′-hydroxyphenyl-4-hydroxybenzoate

Krigbaum, W. R.; Kotek, Richard; Ishikawa, Tomohiro; Hakemi, H.; Preston, J.

doi:10.1016/0014-3057(84)90042-9

Cited by 59 publications

(13 citation statements)

References 13 publications

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“…The similar observations, but for polyesters prepared by esterification were earlier reported by Krigbaum et a/. 20 As it is seen from Table II, the condensation of SEB and/or SUB with bisphenol modified with lateral CH 3 -substituent (DMeBP-2 or DMeBP-3) generally leads to polyesters of lower transition temperatures (both T m and T;) and broadened temperature range of liquid crystalline phase. However, depending on the position of substitution the various shifts of the temperature of appearance of nematic phase were observed.…”

supporting

confidence: 68%

Preparation and Properties of Thermotropic Mesogenic Polyesters

Makaruk¹,

Polanska²,

Ksiezakowska³

et al. 1985

Polym J

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ABSTRACT:The effect of the chemical structure and stereogeometry of mesogen on the liquid crystalline properties of thermotropic main-chain polyesters was studied by means of DSC and polarized microscopy for three series of polymers. The polyesters obtained from modified 4,4'-dihydroxybenzophenone (DHBP) and sebacoyl (SEB) or suberoyl (SUB) dichlorides did not exhibit the mesogenic properties. Modification of DHBP in this case consisted in replacement of ketone linkage by between two aromatic rings. The same bisphenol, however, when mixed with CC12 another (showing meso genic behaviour) enhanced the liquid crystalline properties of the copolyesters, namely increasing the temperature range of liquid crystalline phase. The condensation of SEB or SUB with DHBP modified by lateral substitution (at various positions) of one aromatic ring with CH3 group lead to polyesters of lower temperatures of the transition from crystal to nematic phase and mesophase to isotropic liquid, as compared to parent polymers (i.e., polyesters ofDHBP+SEB or SUB). Different shifts of those temperatures with the position of substitution have been observed and it was found less pronounced for 3-substituted than 2-substituted bisphenols. Temperature ranges of mesophases also depended on the structure of bisphenols and were broader for 3-substituted DHBP. Therefore, the stereogeometry of the polymer molecules and the bulkiness of their substituents are considered the most important parameters in controlling the mesogenic properties of thermotropic, rigid-flexible polyesters with mesogens incorporated in the main chain.

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supporting

confidence: 68%

Preparation and Properties of Thermotropic Mesogenic Polyesters

Makaruk¹,

Polanska²,

Ksiezakowska³

et al. 1985

Polym J

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“…Adipoyl chloride was synthesized by refluxing a mixture of adipic acid and thionyl chloride, followed by distillation under vacuum. Aliphatic diols (n) were distilled under vacuum (6,7) or recrystallized from methanol (8)(9)(10). Diphenyl ether was distilled under vacuum prior to use.…”

Section: Methodsmentioning

confidence: 99%

“…Moreover, an attempt to prepare such regular polyesters by esterexchange reactions with monomers containing ester bonds (CAC) does not necessarily contribute to the formation of polymers with a regular structure. [7] Thus, in this work, all polymers with a regular structure were prepared by a conventional high-temperature solution polycondensation in diphenyl ether from the diacyl chloride of 4,4 0 -(adipoyldioxy)dicinnamic acid and alkane diols of various methylene length or PEG with a widely varying molecular weight (M w ) according to Scheme 1. The liberated HCl was removed with a slow stream of nitrogen.…”

Section: Synthesis Of Polymersmentioning

confidence: 99%

Synthesis and Characterization of Photocrosslinkable Biodegradable Polymers Derived from 4‐Hydroxycinnamic Acid

Nagata

Hizakae

2003

Macromolecular Bioscience

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A novel series of photocrosslinkable biodegradable polymers was prepared by a high‐temperature solution polycondensation from a dichloride of 4,4′‐(adipoyldioxy)dicinnamic acid (CAC) and alkane diols of various methylene lengths (HO(CH2)nOH; n = 6–10) or poly(ethylene glycol)s (PEG) of various molecular weights $(\bar M = 200 - 8300)$. The CAC was synthesized by the condensation of adipoyl chloride and 4‐hydroxycinnamic acid. The chemical structures and properties of these polymers were characterized by elemental analysis, ultraviolet‐visible spectroscopy (UV‐VIS), Fourier transform infrared spectroscopy (FT‐IR), 1H NMR spectroscopy, differential scanning calorimertry (DSC), and thermogravimetry (TG). All polymers had a high molecular weight and good solubility in organic solvents. DSC showed that Tm values of CACn (134–180 °C) were much higher than those of CACEm (25–56 °C). The CACE200 degraded very rapidly in the buffer solutions (pH 7.2) of Ps. Cepacia or Rh. delemar lipase at 37 °C, while CACn resisted the hydrolysis by these lipases during the test period. The ultraviolet light irradiation (λ ≥ 280 nm) caused the photocrosslinking reaction by an intermolecular dimerization at ambient temperature without a photosensitizer, as examined by UV‐VIS, FT‐IR spectroscopy, and gel formation. The gels prepared from CACEm (m ≈ 1 000) were swollen in water and showed characteristic properties of a hydrogel. The irradiation time and the molecular weight of PEGs controlled the degree of swelling of these hydrogels. The CACE8 300 gel irradiated for 20 min showed the largest degree of swelling of 10.5.Weight loss of a CACE200 film as a function of time in a phosphate buffer solution containing no lipase (□), Ps. cepacia lipase (•), or Rh. delemar lipase (○) at 37 °C.magnified imageWeight loss of a CACE200 film as a function of time in a phosphate buffer solution containing no lipase (□), Ps. cepacia lipase (•), or Rh. delemar lipase (○) at 37 °C.

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“…Examination by optical microscopy did not reveal any liquid-crystalline (LC) phase. This negative result is an indication of the expected nearly random sequence, because blocks of the diphenol 26 and aliphatic dicarboxylic acids are known to form a LC-phase over a broad temperature range 36,37) .…”

Section: New Resultsmentioning

confidence: 99%

Ring-opening polycondensations

Kricheldorf¹

2000

Macromol. Rapid Commun.

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Thermotropic homopolyesters—VI. A study of polymers based on 4′-hydroxyphenyl-4-hydroxybenzoate

Cited by 59 publications

References 13 publications

Preparation and Properties of Thermotropic Mesogenic Polyesters

Preparation and Properties of Thermotropic Mesogenic Polyesters

Synthesis and Characterization of Photocrosslinkable Biodegradable Polymers Derived from 4‐Hydroxycinnamic Acid

Ring-opening polycondensations

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