replacing bifunctional calamitic cross-linker with bifunctional triphenylene-based
cross-linker in different loading concentrations (Disch et al. 1995). Table 14 summarizes the thermal transitions of these polymers.
Discotic Hyperbranched Polymers
Discotic Hyperbranched Polymers Based on Hexa-PeriHexabenzocoronene
Müllen and co-workers reported the synthesis of hexa-peri-hexabenzocoronene
(HBC) hyperbranched polymers (Brand et al. 2000). Hexasubstituted hexa-perihexabenzocoronene derivatives substituted with terminal acryloyl 79.1 and
methacryloyl 79.2 moieties were prepared via cobalt octacarbonyl catalyzed
cyclotrimerization of suitably substituted hexaphenylbenzenes followed by an oxidative cyclodehydrogenation with iron (III) chloride dissolved in nitromethane.
Hyperbranched polymers of HBC were achieved via thermal polymerization of
HBC derivatives 79.1 and 79.2 in liquid crystalline phase. Columnar superstructure
of liquid crystalline phase was preserved during and after polymerization and was
found to be stable between À100 to 300
C (Scheme 16).
Discotic Hyperbranched Polymers Based on Alkynylbenzene
Suzuki and Koide (2001) synthesized alkynylbenzene-based discotic hyperbranched
polymers. For this, the monomeric hexyne 80 having six terminal double-bond
containing biphenyl units was prepared. This monomer 80 was then photopolymerized to yield the polymer. The hyperbranched polymer showed glass transition at 51
C and exhibited liquid crystalline behavior above 230
C up to
decomposition due to high cross-linked network.
Scheme 16 Synthesis of discotic hyperbranched polymers based on hexa-peri-hexabenzocoronene: (i) LiAlH 4 in THF, (ii) N,N-dimethylaniline, 2,6-di-tertbutyl-p-cresol in THF,
acryloyl chloride, or methacryloyl chloride (redrawn from Brand et al. 2000)
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S. Setia et al.
cross-linker in different loading concentrations (Disch et al. 1995). Table 14 summarizes the thermal transitions of these polymers.
Discotic Hyperbranched Polymers
Discotic Hyperbranched Polymers Based on Hexa-PeriHexabenzocoronene
Müllen and co-workers reported the synthesis of hexa-peri-hexabenzocoronene
(HBC) hyperbranched polymers (Brand et al. 2000). Hexasubstituted hexa-perihexabenzocoronene derivatives substituted with terminal acryloyl 79.1 and
methacryloyl 79.2 moieties were prepared via cobalt octacarbonyl catalyzed
cyclotrimerization of suitably substituted hexaphenylbenzenes followed by an oxidative cyclodehydrogenation with iron (III) chloride dissolved in nitromethane.
Hyperbranched polymers of HBC were achieved via thermal polymerization of
HBC derivatives 79.1 and 79.2 in liquid crystalline phase. Columnar superstructure
of liquid crystalline phase was preserved during and after polymerization and was
found to be stable between À100 to 300
C (Scheme 16).
Discotic Hyperbranched Polymers Based on Alkynylbenzene
Suzuki and Koide (2001) synthesized alkynylbenzene-based discotic hyperbranched
polymers. For this, the monomeric hexyne 80 having six terminal double-bond
containing biphenyl units was prepared. This monomer 80 was then photopolymerized to yield the polymer. The hyperbranched polymer showed glass transition at 51
C and exhibited liquid crystalline behavior above 230
C up to
decomposition due to high cross-linked network.
Scheme 16 Synthesis of discotic hyperbranched polymers based on hexa-peri-hexabenzocoronene: (i) LiAlH 4 in THF, (ii) N,N-dimethylaniline, 2,6-di-tertbutyl-p-cresol in THF,
acryloyl chloride, or methacryloyl chloride (redrawn from Brand et al. 2000)
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S. Setia et al.