Abstract
Land-fill test of poly (L-lactic acid) blended with wheat bran (PLA/Bran blend) was carried out at two places, Kanazawa and Tsukuba (Japan). The test pieces were prepared by injection molding method. The mechanical properties in the blend sample considerably decreased with exposure time as compared with that of non-blended PLA. Further the molecular weight of PLA in the blended one decreased in one month. On the other hand, that of non-blended PLA hardly decreased under the same conditions. The number of microorganism on the surface of the blended test piece was from 100 to 10000 times as many as that on the non-blended one. The decrease of mechanical properties in the blend can be attributed to the effect of microorganism. Additionally, any clear difference was not observed in the results between Kanazawa and Tsukuba, though the humidity and the temperature of these places in the atmosphere were different from each other in winter.
