| STRUCTURE |
The composition and the sequence of the comonomers in p(SA:FA) can be estimated from the 'H-NMR spectrum. The ratio between fumaric acid and sebacic acid comonomers is determined from the ratio of the olefinic protons at 6.9 (2H, fumaric acid) and aliphatic protons at 1.34 (8H, sebacic acid). For example, for a prepolymer originally having a calculated 50:50 molar ratio, the ratio determined from .sup.1 H-NMR is 46:56 and for a polymer having an intended ratio of 15:85, the prepolymer showed a ratio of 17:81 by .sup.1 H-NMR. The sequence of the polymers was estimated as follows: the aliphatic protons (2CH.sub.2) of the methylenes conjugated with the anhydride bond of sebacic acid split into two triplets, one at .delta.=2.447 ppm (j=7.5 Hz) and one at .delta.=2.545 ppm (j=7.5 Hz). The olefinic protons (2H) are split into two singlets, at .delta.=6.97 and .delta.=2.447 ppm. Both split peaks show 1:1 integration ratios. These splittings are presumably due to the type of anhydride bonds in the polymer: anhydride bonds of sebacic acid-fumaric acid ( .delta.=2.545 ppm), anhydride bonds of sebacic acid-sebacic acid ( .delta.=2.447 ppm), anhydride bonds of fumaric acid-sebacic acid ( .delta.=6.91 ppm) and anhydride bonds of fumaric acid-fumaric acid ( .delta.=6.97). .sup.13 C NMR spectra of copolymers of sebacic and fumaric acid have characteristic peaks (ppm): carboxylic carbons at 160-170, olefinic carbons at 132-136, and aliphatic carbons at 24-35
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