Synthesis and thermal properties of side‐chain liquid crystalline polyethers with racemic and chiral backbone

Taton, Daniel; Borgne, Alain Le; Spassky, Nicolas; Friedrich, Claude; Noël, Claudine

doi:10.1002/pat.1994.220050401

Cited by 14 publications

(14 citation statements)

References 35 publications

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“…More recently, several authors have reported a set of racemic and chiral glycidylic compounds leading to polymers with 4‐cyanobiphenyl and 4‐alkoxybiphenyl mesogenic groups 20–22. These monomers were polymerized by using cationic (BF 3 ·Et 2 O),20 anionic (CsOH and t ‐BuOK/DMSO),23, 24 and ionic coordinative (Et 3 Al/AcAc/H 2 O)24 initiators. The low‐molecular‐weight materials obtained show nematic, smectic, or cholesteric mesophases, but again, polymerization with (Et 3 Al/AcAc/H 2 O) failed to yield soluble materials because of the high molecular weight and tacticity of the samples.…”

Section: Introductionmentioning

confidence: 99%

Studies on the modification of poly(ω‐bromoalkyl‐1‐glycidylether)s with 4′‐methoxybiphenyl‐4‐oxy mesogenic groups

Montornés¹,

Reina²,

Ronda³

2005

J. Polym. Sci. A Polym. Chem.

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A series of poly[ω‐(4′‐methoxy‐biphenyl‐4‐oxy)alkyl‐1‐glycidylether]s were synthesized by chemically modifying the corresponding poly(ω‐bromoalkyl‐1‐glycidylether)s with the sodium salt of 4‐hydroxy‐4′‐methoxybiphenyl. New high‐molecular‐weight side‐chain liquid‐crystalline polymers were obtained with excellent yields and almost quantitative degrees of modification. They were all insoluble in THF and other common solvents. Characterization by 13C NMR confirmed that all the polymers had the expected structure. The liquid crystalline behavior of the polymers was analyzed by DSC and polarized optical microscopy, and mesophase assignments were confirmed by X‐ray diffraction studies. Polymers that had alkyl spacers with n = 2 and 4 were smectic C, those that had spacers with n = 6 and 8 were nematic cybotactic, and those that had longer spacers (n = 10 and 12) were smectic C again. © 2005 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 43: 5998–6006, 2005

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Section: Introductionmentioning

confidence: 99%

Studies on the modification of poly(ω‐bromoalkyl‐1‐glycidylether)s with 4′‐methoxybiphenyl‐4‐oxy mesogenic groups

Montornés¹,

Reina²,

Ronda³

2005

J. Polym. Sci. A Polym. Chem.

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“…The ring opening polymerization of glycidyl derivatives was tested with three different initiator systems: a cationic one, trityl hexafluorophosphate,28 and two anionic ones, potassium t ‐butoxide29 and the system polyiminophosphazene base t ‐Bu‐P 4 in combination with 3,5‐di‐ t ‐butylphenol 23. In the case of trityl hexafluorophosphate, two different solvents and temperatures were tested: dichloromethane at 40 °C and THF at 60 °C.…”

Section: Resultsmentioning

confidence: 99%

Vinyl‐terminated side‐chain liquid‐crystalline polyethers containing mesogenic benzylideneaniline moieties

Callau

Giamberini

Reina

et al. 2006

J. Polym. Sci. A Polym. Chem.

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The synthesis of two vinyl‐terminated side‐chain liquid‐crystalline polyethers containing benzylideneaniline moieties as mesogenic cores was approached in two different ways: by chemically modifying poly(epichlorohydrin) with suitable mesogenic acids or by polymerizing analogous glycidyl ester or glycidyl ether derivatives. In all the conditions tested, the first approach led to materials in which the imine group was hydrolyzed. The second approach led to the desired polymers PG2a and PG2b, but only from the glycidyl ether derivatives and when the initiator was the system that combined polyiminophosphazene base t‐Bu‐P4 and 3,5‐di‐t‐butylphenol. These polymers were chemically characterized by IR and 1H and 13C NMR spectroscopies. The estimated degrees of polymerization ranged from 30 to 36. The liquid crystalline behavior of the synthesized polymers was studied by differential scanning calorimetry, polarized optical microscopy (POM) and X‐ray diffraction. Both polymers behave like liquid crystals and exhibited a single mesophase, which was recognized as a smectic C mesophase, probably with a bilayer arrangement, i.e., a smectic C2 mesophase. The crosslinking of both polymers was performed with dicumyl peroxide as initiator, which led to liquid crystalline thermosets. POM and X‐ray diffraction confirmed that the mesophase organization mantained on the crosslinked materials. © 2006 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 44: 1877–1889, 2006

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“…Enantiomorphic site control would have influence on the ratio of the different triads, but there would not be a relation with the molecular weight. In addition, for the homopolymerization of mesogenic epoxides in the work of Taton et al 21,22) , there was no indication of such phenomena. Chain end control might be a good explanation if we realize that the various fractions have different carbonate contents.…”

Section: Stereochemistrymentioning

confidence: 87%

“…Unfractionated sample marked by filled triangle. Theoretical curves plotted as a reference this is illustrated by the fact that Taton et al 21,22) could recently prepare cholesteric SC-LC polyethers, whereas racemic epoxides gave nematic mesophases.…”

Section: Nmr Analysismentioning

confidence: 98%

Synthesis and characterization of novel side-chain liquid crystalline polycarbonates, 4. Synthesis of side-chain liquid crystalline polycarbonates with mesogenic groups having tails of different lengths

Jansen¹,

Addink

Nijenhuis

et al. 1999

Macromol. Chem. Phys.

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SUMMARY: Side-chain liquid crystalline polycarbonates with alkoxyphenylbenzoate side groups, having a short spacer and tails ranging from 1 to 8 C-atoms, were synthesized. The polymers were prepared by an organo-zinc catalysed copolymerization of carbon dioxide and mesogenic 4-alkoxyphenyl 4-(2,3-epoxypropoxy)benzoates. Model polycarbonates were prepared by copolymerization of glycidyl phenyl ether (GPE) and carbon dioxide and by terpolymerization of GPE, propylene oxide and CO 2 . The copolymerizations of LC monomers were carried out at 70 8C in an autoclave at 60 atm CO 2 pressure in dioxane as the solvent. Catalysts based on diethylzinc and water or diethylzinc and resorcinol were used. High catalyst concentrations (up to 20 mol-% on the basis of diethylzinc with respect to epoxide) and long reaction times (72 h) were found to be necessary for acceptable yields and reasonable molar masses. The resulting polymers had a high polydispersity and the maximum yield was about 30%. A major side product, formed directly from CO 2 and epoxide, as well as indirectly by depolymerization, was the corresponding five-membered cyclic carbonate. The polymers on average contained about 30 mol-% of ether units and 70 mol-% of carbonate units due to a weak tendency of the epoxides to undergo homopolymerization. 1 H and 13 C NMR analysis revealed detailed information about the overall ether content and the distribution of the ether and carbonate groups in the chain, as well as the tacticity of the polymers. Surprisingly, the monomer distribution and the tacticity were molecular weight dependent. Some possible explanations for these phenomena are suggested.

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Synthesis and thermal properties of side‐chain liquid crystalline polyethers with racemic and chiral backbone

Cited by 14 publications

References 35 publications

Studies on the modification of poly(ω‐bromoalkyl‐1‐glycidylether)s with 4′‐methoxybiphenyl‐4‐oxy mesogenic groups

Studies on the modification of poly(ω‐bromoalkyl‐1‐glycidylether)s with 4′‐methoxybiphenyl‐4‐oxy mesogenic groups

Vinyl‐terminated side‐chain liquid‐crystalline polyethers containing mesogenic benzylideneaniline moieties

Synthesis and characterization of novel side-chain liquid crystalline polycarbonates, 4. Synthesis of side-chain liquid crystalline polycarbonates with mesogenic groups having tails of different lengths

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