CHARACTERIZATION OF NONIONIC AND CATIONIC AMINE-FUNCTIONAL POLYMERS BY AQUEOUS SEC-MALLS

Molecular weight, root-mean-square radius, and conformational informat ion obtained from aqueous size exclusion chromatography (SEC) and mult iangle laser light-scattering (MALLS) detection are examined for amine -functional polymers. These include homopolymers and copolymers of pol y(ethenylformamide) and cationic poly(vinylamine). Light-scattering st udies for poly(ethenylformamide) employing 15 angles of detection are used to calculate molecular weights as high as 700,000 daltons with a root-mean-square radius of nearly 50 nm. Calculated conformational coe fficients indicate a random-coil configuration at low molecular weight s and a more compacted conformation at high molecular weights. Molecul ar weights and root-mean-square radius values for cationic poly(vinyla mine) are determined using a three-angle MALLS detector. Root-mean-squ are radius is strongly dependent on the ionic strength of the mobile p hase. Cationic poly(vinylamine) exhibits a rod-like conformation at bo th low and high ionic strength. Explanations are proposed for this beh avior. (C) 1996 John Wiley & Sons, Inc.