Deterioration simulation system is proposed as a tool to realize service life prediction. Material properties can be expressed as an advanced Arrhenius' Model which includes suffering environmental degradation factors, elapsed time and shift factor for devitalization of stabilizers. The tiny degradation in every hourly time elements are integrated for whole outdoor exposed period referring hourly black panel temperature, solar UV radiation and wetting time estimated from meteorological factors observed around Japan. Material coefficients in the model were determined to be fitted with the results of artificial accelerating tests. Deterioration is simulated virtually on an Excel template referring the database of degradation factors and is shown on a chart of property versus elapsed time.
Composition gradient of the blend film of polyethylene terephthalate (PET) and polyethylene oxide (PEO) was observed by using polarization microscope and FT-IR. The blend film was prepared by annealing under the temperature gradient after melting. Cross section structure changed from the sea island to graded and step structure by increasing annealing time. As for the driving force for the formation of graded and step structure, temperature difference between bottom side and surface side of the melted sheet of the polymer blend was getting involved. Such a full scale phase separation as graded and step structure were suggested to be applied as a way to give high function to the recycling article of PET.
The composting degradation tests of poly (L-lactic acid) (PLA) were carried out in aerobic and anaerobic conditions at different temperatures (25-50°C). The degradation rate of PLA was fastest in anaerobic condition at 50°C. In this condition, concentrations of fatty acids generated in the compost were highest. The result suggested that the acids catalyzed the hydrolysis of PLA in the compost. The degradation tests of PLA were also conducted in the fatty acid solutions (acetic acid, propionic acid, and butyric acid) as well as ammonia solutions separately. The results suggested that these acids and base strongly promoted the degradation of PLA.