| 초록 |
Recently, the automobile industry has been increasingly interested in lightweight materials as regulations on international fuel efficiency and greenhouse gas emissions have been strengthened. High specific mechanical properties would be achieved if hollow glass microsphere (HGM) with less than the density of 0.5 g/cm2 are put together with glass fiber (GF) to meet industrial needs. However, we found that damage to the HGM due to the both extrusion and injection molding process and increase in the viscosity due to the high content of the inorganic fillers. Through aliphatic hyperbranched polyesters based on 2,2-bis(methylol)propionic acid, melt flow index doubled compared to the PA 6/HGM/GF composite, reducing the breakage to the HGM observed by SEM and two methods of density measurement, resulting in a surface clearness of the composite, and an unexpected increment in tensile strength from 59 MPa to 73 MPa and flexural modulus from 4032 MPa to 4424 MPa. |
