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Poly(ethylene terephthalate), recycled from soft-drink bottle
wastes, is depolymerized by glycolysis in excess ethylene
glycol (EG) at 190 .degree.C in the presence of zinc acetate
catalyst. The glycolyzed products are reacted with adipic acid
through polycondensation to give polyester polyols. By varying
the ratio of hydroxyl to carbonyl group, polyester polyols with
different molecular weights are obtained. A series of polyure-
thanes with different isocyanate to hydroxyl ratios are
synthesized by reacting the polyester polyol with diisocyan-
ate. These cast polyurethanes obtained are characterized by DSC
and TGA.
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