Abstract
Recent years, emission of greenhouse gases discharged by the consumption of fossil fuels are increasing. As a result, huge problems such as global warming and environmental pollution have been created. Therefore, it is important to reduce use of fossil fuels and develop the alternative to petroleum. Poly(lactic acid) (PLA) is a biomass and biodegradable polymer, which is expected as an alternative material of other polymers. However, PLA has some disadvantages such as high viscosity , high density, low thermal resistance and so on for injection moldings. The use of PLA in injection molding parts is still limited due to these disadvantages. In order to solve these disadvantages of PLA, we have investigated the injection molding of PLA by applying Supercritical Fluid (SCF) technique. In this study, it is revealed that injection pressure decreased to about 60% as compared with conventional injection pressure. And we also discuss the mechanical, thermal and dielectric properties on the basis of the results of tensile test, Izod test, DMA, and dielectric measurement. Specific tensile modulus and strength of specimens decreased on increasing the percentage of foam in the specimens. On the other hand, specific Izod impact strength of specimens didn't decrease. In addition, the value of dielectric constant and loss decreased on increasing the percentage of foam in the specimens. Therefore, by this SCF foaming technique we showed that we can easily produce impact-resistant and low dielectric materials of PLA.
