The processes in the polycondensations of adipic acid (AD) /trimethylolpropane (TMP) / 1, 6 -hexanediol (1, 6 -HD), isophthalic acid (iPA) /TMP/ 1, 6 -HD and AD/iPA/TMP/ 1, 6 -HD without a catalyst were studied by
13C NMR spectroscopy.
13C NMR spectroscopy enable the quantitative determination of the conversion of 1, 6 -HD and TMP, and the polycondensation mechanism. The following are results we obtained : (1) TMP was found to be less reactive than 1, 6 -HD. (2) The ratio of TMP forms (free, monoesterified, diesterified, and triesterified) in the final product did not agree with that calculated from the ratio of the monomer in the recipe. However, the ratio agreed with that calculated on the basis of the conversion of TMP into the polyester. From the results above we can presume that in spite of the same reactivity of free, monoesterified, and diesterified TMPs, TMP is less reactive than 1, 6 -HD in the polycondensation.
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