Improvement of Processability of PCL and PBS Blend by Irradiation and its Biodegradability

Poly(ε-caprolactone) (PCL) was blended with poly(butylene succinate) (PBS), (PCL/PBS = 30/70) to improve the heat stability of PCL. The processability of the blended samples (PHB02) was improved due to enhancing of melt strength by γ-rays irradiation in the dose range between 10 and 50 kGy. High speed production of a thin film and production of foam have been achieved by this process. The soil degradation test showed that PHB02 film buried in the soil was almost degraded (97%) after two months and completely degraded after two and a half months. On the contrary, the sample on the surface degraded to only 3.5% after four months. From these findings it was confirmed that microorganisms contribute to degradation in the soil. In the case of PHB02 foam samples, 65% degradation was achieved after four months. The PHB02 sample used as garbage bags was well degraded (almost 50%) after a two months burial test. The enzymatic degradation test showed that after treatment for 24 h, the weight loss of PHB02 irradiated with 30 kGy and unirradiated samples were 80% and 90%, respectively. Enzymatic degradation for PHB02 films led to the suggestion that the biodegradation process proceeds from the surface to the inside of the sample by erosion.