Microstructure of alkoxy and alkyl substituted isocyanate copolymers determined by desorption chemical ionization mass spectrometry

Copolymers comprised of 3-(2-(2-methoxy)ethoxy)propyl isocyanate (monomer G) with 1-isocyanato-4,4,5,5,6,6,7,7,8,8,9,9,9-tridecafluorononane (monomer F) as well as copolymers of monomer G and n-hexylisocyanate (monomer H) were examined by desorption chemical ionization mass spectrometry (DCI-MS) to obtain information on the monomer distributions in the copolymers. The monomer distributions were deduced from the abundances of various protonated and ammoniated trimers in the ammonia DCI mass spectra using zero-order Markovian statistics. Both copolymers comprised of monomers G and F as well as monomers G and H were found to have random monomer distributions. This behavior is in contrast to copolymers comprised of monomers F and H whose dissimilar side chains resulted in non-random distributions.