Yuji Kageyama

Improvement of Heat Resistance for Bioplastics

We studied the adoption of plastics derived from plants (bioplastics) such as poly(lactic acid) (PLA) for automotive parts in order to contribute to suppressing the increase in CO, emissions. For this application. major improvements of heat and impact resistance are needed. As a method to improve heat resistance, we developed PLA.combined with clay of high heat resistance. As a result. we succeeded in synthesizing a PLA-clay nanocomposite using 18(OH) 2 -Mont. In-mold crystallization of PLA-clay nanocomposite lead to the great suppression of storage modulus decrease at high temperature. which in turn improved the heat resistance of PLA.

INVESTIGATION OF BIO-PLASTICS FOR AUTOMOTIVE PARTS

We studied the application of Bio-plastics (plastics made from plants) such as poly(lactic acid) (PLA) to automotive parts. To apply this material to automotive plastic parts, major improvement is required for thermal and impact performance. From the viewpoint of suppressing the increase CO2 emissions, we attempt to improve the performance of PLA by combining with natural fiber. As the result, we could improve both thermal and impact performance. In addition, we could achieve higher modulus and lower bulk density, which lead to the weight reduction of automotive parts. (A) For the covering abstract see ITRD E121867.

Improvement of Crystallization and Mechanical Properties of PLA by Means of Clay Nanocomposite

Some composite materials of poly (lactic acid) (PLA) with organophilic clays and an organic crystal accelerator (OCA) were prepared by melt compounding method to improve the rate of crystallization and mechanical properties, especially heat distortion temperature (HDT). The PLA/clay nanocomposite with 2.9wt% of finely dispersed organophilic clay and 1wt% of the OCA showed an exothermic peak corresponding to its crystallization at 1.9 minutes in the isothermal measurement of DSC at 100°C from its molten state, although PLA itself did not show a clear peak in the same procedure. Crystallized specimens of the nanocomposite were well obtained by injection molding when the hold time was set at more than 90 seconds. The HDT of the specimens that were held for more than 120 seconds in the mold exceeded 120°C. It is about 65°C higher than amorphous PLA. The crystallized specimen with 1wt% of the clay showed higher tensile modulus and Izod impact strength than the amorphous one.