Abstract
To give properties of both high heat resistance and impact strength，which are required for Industrial components，to poly-L-lactic acid (PLA)，we sought to create a compound that includes an agent granting flexibility，a nucleating agent of proprietarily developed starch and poly-D-lactic acid. We also used natural rubber as a flexible phase，and epoxidizednatural rubber，which joins the flexible and rigid crystalline phases，and poly(carbodiimide) (PCDI) as a hydrolysis inhibitor and anadhesionbetween NR/ENR and PLA to create a new compound for injection molding that uses morethan 97% plant material. Compared to PLA itself，the injection molding products obtained from the modified PLA compound (97% plant material) had an increased heat resistance of about 50℃ and 10 times greater impact strength from the evaluation of the impact and thermal mechanical properties of the compounds by JIS K7160 and JIS K7191-2Be. The physical improvements in PLA are due to the bonding of the uniformly distributed PLA crystalline phase by scanning probe microscopy. The effect of molecular weight of PCDI or amount of PCDI added was also examined on their mechanical properties or PLA crystallization rate.
