Multifunctional Captodative Monomers: Urea Containing Dehydroalanines and Their Polymers
Polymers and High Performance Materials
The synthesis and characterization of a new family of urea derivatives of dehydroalanines are described. Ten alkyl and seven aryl monomer and polymer urea derivatives of dehydroalanine methyl ester were synthesized. The radical chain end formed from these monomers during polymerization is assumed to be especially stabilized by the synergistic captodative effect involving electron-donating and -withdrawing substituents on the radical carbon. This is consistent with rapid formation of high molecular weight polymers as indicated by intrinsic viscosity values up to 1.7 dL/g. Viscosity values for THF-soluble polymers were consistent with SEC estimates for random coil polymers of several million molecular weight. FT-IR and C-13 NMR spectra confirmed compound structures. X-ray diffractograms showed side-chain crystallinity in the longer alkyl urea derivatives as exemplified by the n-octadecyl polymer. The availability of a wide range of isocyanate precursors to the monomers makes possible a variety of derivatives possessing intra- and inter-molecular hydrogen-bonding units in the polymers.
Kurz, D. W.,
Mathias, L. J.
(1991). Multifunctional Captodative Monomers: Urea Containing Dehydroalanines and Their Polymers. Macromolecules, 24(1), 35-41.
Available at: http://aquila.usm.edu/fac_pubs/6928