Since the introduction of poly(ethy1ene terephthalate) (PET) and polyamide 6, many attempts have been made to synthesize other polymers with a large variety of properties. One of the polymers which has been studied extensively is polypivalolactone (PPVL), formed by ring-opening polymerization of pivalolactone (PVL). PPVL is a highly crystalline aliphatic polyester (≥75% crystallinity) with mechanical properties comparable with those of PET and polyamide 6. Although the technology and expertise to prepare PPVL on a commercial scale was already available in the early 1970s, most of the projects concerning PPVL, especially in fiber applications, were discontinued on the basis of economic considerations.