Condensation polymerization of ARB type monomers in CSTRs wherein the monomer is R times more reactive than other homologues

Abstract

Molecular weight distributions (MWDs) and their moments for the polycondensations of ARB-type monomers which do not obey the equal reactivity hypothesis, in ideal continuous-flow stirred tank reactors (CSTRs), have been studied. The model assumes that monomers react with monomers and higher homologues at a rate which is R times that of all other reactions in the system. It is found that the polydispersity indices are much higher than for the batch reactor. The MWD has been found to split into two curves, one for even-ordered homologues and one for odd-ordered ones. For R < 1, these curves merge for higher homologues, whereas for R > 1, firstly there is a fall in the mass fraction from monomer to the dimer, then a rise to a broad maxima after which they decay slowly. Results are also compared with those for a different kinetic scheme in which the monomer reacts only with a monomer at a rate R times that characterizing all other species.