title: Molecular weight between entanglements for κ- and ι-carrageenans in an ionic liquid.
abstract: The molecular weight between entanglements (Me) for κ- and ι-carrageenans, sulfated galactans, was examined in concentrated solutions using an ionic liquid 1-butyl-3-methylimidazolium acetate as a solvent. The dynamic viscoelasticity data for the solutions measured at different temperatures were overlapped according to the time-temperature superposition principle, and the obtained master curves exhibited the flow and rubbery plateau zones, being typical of concentrated polymer solutions having entanglement coupling. The values of Me for κ- and ι-carrageenans in the solutions were determined from the plateau moduli. Then the values of Me in the molten state (Me,melt) estimated as a material constant to be 6.6×10(3) and 7.2×10(3), respectively. The close values of Me,melt for κ- and ι-carrageenans indicate that 4-sulfate group of ι-carrageenan are not so influential for the entanglement network. Compared with agarose, a non-sulfate galactan, carrageenans have larger values of average spacing between entanglements.
authors.affiliation: Department of Material Chemistry, Graduate School of Engineering, Kyoto University, Nishikyo, Kyoto 615-8510, Japan. Electronic address: horinaka.junichi.5c@kyoto-u.ac.jp.
authors.forename: Jun-ichi
authors.initials: J
authors.lastname: Horinaka
authors.affiliation: Department of Material Chemistry, Graduate School of Engineering, Kyoto University, Nishikyo, Kyoto 615-8510, Japan.
authors.forename: Yuhei
authors.initials: Y
authors.lastname: Urabayashi
authors.affiliation: Department of Material Chemistry, Graduate School of Engineering, Kyoto University, Nishikyo, Kyoto 615-8510, Japan.
authors.forename: Xiaochen
authors.initials: X
authors.lastname: Wang
authors.affiliation: Department of Material Chemistry, Graduate School of Engineering, Kyoto University, Nishikyo, Kyoto 615-8510, Japan.
authors.forename: Toshikazu
authors.initials: T
authors.lastname: Takigawa
mesh_terms: D002351:Carrageenan / Q000737:chemistry*; D007093:Imidazoles / Q000737:chemistry*; D052578:Ionic Liquids / Q000737:chemistry*; D008970:Molecular Weight
chemical_list: C525963:1-butyl-3-methylimidazolium; D007093:Imidazoles; D052578:Ionic Liquids; D002351:Carrageenan
keywords: Carrageenan; Ionic liquid; Molecular weight between entanglements