A high performance liquid chromatography method to determine monomer reactivity ratios in copolycondensation of bis(4-hydroxybutyl) terephthalate and bis(2-hydroxyethyl) terephthalate

Abstract The rate constants of cross reactions in the copolycondensation of bis(4-hydroxybutyl) terephthalate (BHBT) and bis(2-hydroxyethyl) terephthalate (BHET) as monomers, k 12 and k 21 , could be determined by using the results obtained from a high performance liquid chromatography (HPLC) analysis. BHBT and BHET were polymerized and copolymerized at 260, 270, and 280°C, in the presence of titanium tetrabutoxide as a catalyst. Applying 2nd order kinetics for polycondensation, the rate constants of polycondensation of BHBT and BHET, k 11 and k 22 , were calculated. It was found that the monomer reactivity ratios of BHBT were much larger than those of BHET and the differences between monomer reactivity ratios were decreased with increasing polycondensation temperature.