Optical rotation of random copolyisocyanates of chiral and achiral monomers

Sergeant and soldier copolymers

Hong Gu, Yo Nakamura, Takahiro Sato, Akio Teramoto, Mark M. Green, Salil K. Jha, Christopher Andreola, Michael P. Reidy

Research output: Contribution to journalArticle

Abstract

Optical rotation (OR) of random copolymers of chiral 2,6-dimethylheptyl isocyanate (NIC) and achiral hexyl isocyanate (HIC) was measured as a function of mole fraction x of the chiral monomer, temperature, and molecular weight, with hexane, 1-chlorobutane, and dichloromethane as the solvents. The data as a function of molecular weight were analyzed by the statistical mechanical theory of copolymers developed (Gu, H.; et al. Polym. J. 1997, 29, 77-84), in which a polyisocyanate chain is modeled by an alternating sequence of left-handed and right-handed helices occasionally interrupted by helical reversals. The theory involves two parameters, the left-handed-right-handed free energy bias, 2ΔGh, and the helical reversal free energy, ΔGr. With appropriate values for these parameters, the experimental OR values were well described by the theory. When compared with poly((R)-i-deuterio-n-hexyl isocyanate (i = 1, 2), the values of ΔGr were nearly the same but those of |2ΔGh| were much larger: 71 ± 14 cal/mol for the terpene derived chiral unit vs 1∼2 cal/mol for the deuterated chiral monomer units. These free energy values are reasonable considering the chemical structures of the respective chiral monomer units.

Original languageEnglish (US)
Pages (from-to)6362-6368
Number of pages7
JournalMacromolecules
Volume31
Issue number18
StatePublished - Sep 8 1998

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Optical rotation
Isocyanates
Free energy
Copolymers
Monomers
Molecular weight
Terpenes
Polyurethanes
Methylene Chloride
Dichloromethane
Hexanes
Hexane
Temperature

ASJC Scopus subject areas

  • Materials Chemistry

Cite this

Gu, H., Nakamura, Y., Sato, T., Teramoto, A., Green, M. M., Jha, S. K., ... Reidy, M. P. (1998). Optical rotation of random copolyisocyanates of chiral and achiral monomers: Sergeant and soldier copolymers. Macromolecules, 31(18), 6362-6368.

Optical rotation of random copolyisocyanates of chiral and achiral monomers : Sergeant and soldier copolymers. / Gu, Hong; Nakamura, Yo; Sato, Takahiro; Teramoto, Akio; Green, Mark M.; Jha, Salil K.; Andreola, Christopher; Reidy, Michael P.

In: Macromolecules, Vol. 31, No. 18, 08.09.1998, p. 6362-6368.

Research output: Contribution to journalArticle

Gu, H, Nakamura, Y, Sato, T, Teramoto, A, Green, MM, Jha, SK, Andreola, C & Reidy, MP 1998, 'Optical rotation of random copolyisocyanates of chiral and achiral monomers: Sergeant and soldier copolymers', Macromolecules, vol. 31, no. 18, pp. 6362-6368.
Gu H, Nakamura Y, Sato T, Teramoto A, Green MM, Jha SK et al. Optical rotation of random copolyisocyanates of chiral and achiral monomers: Sergeant and soldier copolymers. Macromolecules. 1998 Sep 8;31(18):6362-6368.
Gu, Hong ; Nakamura, Yo ; Sato, Takahiro ; Teramoto, Akio ; Green, Mark M. ; Jha, Salil K. ; Andreola, Christopher ; Reidy, Michael P. / Optical rotation of random copolyisocyanates of chiral and achiral monomers : Sergeant and soldier copolymers. In: Macromolecules. 1998 ; Vol. 31, No. 18. pp. 6362-6368.
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