Degradable Polymers. I. Synthesis,Characterization, and Long-Term in Vitro Degradation of a 14C-Labeled Aliphatic Polyester

Poly(tetramethylene adipate) has been synthesized with and without ¹⁴C labeling at different molecular weights. Degradation tests of the labeled powder inoculated with microorganisms showed a decrease in molecular weight (GPC) and first an increase and later a decrease of crystallinity (DSC). These changes also occurred in the inoculated material, and the results indicate that the degradation process was abiotic hydrolysis which first takes place in the amorphous region. The radioactivity measurements showed that the microorganisms are able to degrade further the oligomers formed during the hydrolysis. The rate of degradation is related to the molecular weight. Unlabeled poly(tetramethylene adipate) was extruded and cold drawn to yield oriented fibers. These fibers retained more than 50% of the original tensile strength during 100 days of abiotic in vitro hydrolysis.