In:
Journal of Polymer Science: Polymer Chemistry Edition, Wiley, Vol. 16, No. 8 ( 1978-08), p. 2001-2017
Abstract:
A number of multi‐ N ϵ ‐poly(γ‐benzyl‐ L ‐glutamyl)copoly( L ‐lysine γ‐methyl‐ L ‐glutamate)s with branches having various degrees of polymerization and with various intervals of the grafting sites in the core molecule were prepared in N , N ‐dimethylformamide containing dimethyl sulfoxide by the reaction of N ‐carboxy anhydride of γ‐benzyl L ‐glutamate with random copoly( L ‐lysine γ‐methyl‐ L ‐glutamate)s of different composition with various anhydride‐initiator ratios. The relationship between the intrinsic viscosity measured in a coil solvent, dichloroacetic acid (DCA), and the number‐average molecular weight determined by osmometry was found to be expressed by the Mark–Houwink–Sakurada equation for the multichain copoly(α‐amino acid)s which were made from the same polymeric initiator. The observed α values of the multichain copoly(α‐amino acid)s in the equation were lower than that of linear poly(γ‐benzyl‐ L ‐glutamate). The solvent induced helix–coil transition of the multichain copolymer was investigated in the chloroform‒DCA system by the ORD technique. Two kinds of transition regions were clearly distinguished: The α‐helices of the core molecules underwent the transition at lower DCA concentration and those of the branch chains at higher DCA concentration. The reduced viscosity of the multichain copoly‐(α‐amino acid) increased slightly between the two transition regions, in contrast to the large decrease in the reduced viscosity of linear poly(γ‐benzyl‐ L ‐glutamate) during the helix–coil transition.
Type of Medium:
Online Resource
ISSN:
0360-6376
,
1542-9369
DOI:
10.1002/pol.17.v16:8
DOI:
10.1002/pol.1978.170160817
Language:
English
Publisher:
Wiley
Publication Date:
1978
detail.hit.zdb_id:
3004641-5
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