Synthesis and solution properties of some polysulfobetaines.

摘要

The reaction of diallylamine with 1,3-propanesultone led to the synthesis of the zwitterionic monomer 3-(N,N-diallylammonio) propanesulfonate. The sulfobetaine was cyclopolymerized in water in the presence of sodium chloride using t-butylhydroperoxide as an initiator to afford a polysulfobetaine (PSB) in very good yield. The PSB, upon treatment with sodium hydroxide, was converted into an anionic polyelectrolyte (APE). While the APE was found to be readily soluble in salt-free water, the PSB needed the presence of low molecular weight salts (e.g., NaCl, KI etc, in the range 0.135--1.04 N) for its dissolution. The solution properties of the PSB and APE were studied in some detail by potentiometric and viscometric techniques. Basicity constant of the amine is found to be apparent and as such follow the modified Henderson-Hasselbalch equation; as the degree of protonation of the whole macromolecule increases, the protonation of the amine nitrogens becomes increasingly more difficult. The composition and phase diagram of the aqueous two-phase systems of APE/PSB and poly(ethylene glycol) (PEG) were studied.; A special monomer, sodium N-(3-sulfopropyl)-3-( N,N diallyl amino) propane sulfonate, containing the electrolytic as well as zwitterionic feature incorporated within same molecule, was synthesized. The monomer underwent free radical polymerization in aqueous medium using t-butylhydroperoxide as an initiator to give the corresponding homopolymer, poly(electrolyte-zwitterions) (PEZ). The copolymer of this electrolytezwitterionic monomer with sulfur dioxide was synthesized in dimethyl sulfoxide (DMSO) using azo-bis-isobutyronitile (AIBN) as an initiator. The solution properties of these polymers were discussed in detail. Both the homo and copolymer were found to be readily soluble in water; thus demonstrating the electrolytic behaviour of the PEZs. The PEZs showed polyelectrolytic viscosity behaviour; the intrinsic viscosity values decreased by increasing the ionic strength of its aqueous solutions.