Quantitative studies of interaction between complementary polymers and oligomers in solutions

A theoretical model for interpolymer reaction of the type: matrix + oligomer ? polycomplex has been considered. Matrix and oligomer are complementary macromolecules with the matrix chain length substantially greater than that of the oligomer chain. Theoretical relations connecting the conversion degree in the interpolymer reaction with temperature, oligomer length and oligomer concentration are developed. The limits for application of the considered theoretical model are indicated. High selectivity of the interpolymer reaction with respect to the oligomer chain length is predicted theoretically. The validity of the theoretical relations is demonstrated by the reactions between polycarboxylic acids and polyethylene glycol in aqueous and water-methanol media. The selectivity of the interpolymer reactions with respect to chain length is experimentally proved for the example of fractionated relatively low molecular poly-N-vinyl pyrrolidone complexing with polyacrylic acid.