ABSTRACT:The nylon4 portion in the blend films composed of nylon4 and nylon6 was degraded and completely disappeared within 4 months in two kinds of composted soils gathered from different university farms as well as pure nylon4 film reported previously, while the nylon6 portion remained even after the burial test for 15 months. Nylon4 powder was also degraded to carbon dioxide in the degradation test in an activated sludge obtained from a sewage disposal institution in Kogakuin University. Three species of microoganisms (i.e., ascomytous fungi) were isolated through the inoculation from the nylon4 film partially degraded in the soil on a medium containing nylon4 powder as a carbon source.

Different novel copolymers, ABA-type block copolymers composed of polyamide4 as outer segments and polyoxyethylene as an inner segment and AB-and ABAtype block copolyamides containing polyamide4 and another hydrophilic polyamide derived from a bicyclic lactam, were synthesized by the anionic ring-opening polymerization of 2-pyrrolidone using the corresponding acyllactamtype macromolecular activators. The degradation rate of both block copolymers containing polyamide4 segments in a composted soil was found to decrease with increasing content of the second segments, although they were also hydrophilic and/or biodegradable.