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Molar Mass Analysis of Hydrophobically Modified Hyaluronic Acid by SEC‐MALLS: Facing the Challenges of Amphiphilic Biomacromolecules
Author(s) -
Botha Carlo,
Kuntz JeanFrançois,
Moire Claudine,
Farcet Céline,
Pfukwa Helen,
Pasch Harald
Publication year - 2018
Publication title -
macromolecular chemistry and physics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.57
H-Index - 112
eISSN - 1521-3935
pISSN - 1022-1352
DOI - 10.1002/macp.201800233
Subject(s) - molar mass , polymer , polymer chemistry , chemistry , acrylate , amphiphile , copolymer , acrylic acid , hydrolysis , thermal stability , size exclusion chromatography , multiangle light scattering , chemical engineering , light scattering , organic chemistry , scattering , physics , optics , enzyme , engineering
A size exclusion chromatography–multiangle laser light scattering (SEC‐MALLS) method is developed for determining the molar masses of amphiphilic hyaluronan (HA), consisting of a hydrophilic polymer backbone modified to varying extents with hydrophobic, polymerizable acrylate groups. The polymers are prepared via the base‐catalyzed esterification of HA with acrylic anhydride. Various parameters are investigated including mobile phase composition, temperature, pH, salt type, and concentration in order to find the most suitable conditions for completely dissolving the modified polymers irrespective of the degree of substitution (DS), and for suppressing secondary polymer interactions. The hydrolytic and the thermal stability of the different materials at various experimental conditions are also extensively investigated. HAs with DS varying from 0 to 3.4 are subsequently analyzed at the optimized experimental conditions for the mobile phase being DMSO/H 2 O 60/40(v/v) with 0.05 M LiBr and an operating temperature of 40 °C. The refractive index increments (dn/dc) of the HAs are determined and the results show a dependence of dn/dc on DS.