LIQUID NATURAL RUBBER TOUGHENED POLY(LACTIC ACID) BLEND: EFFECTS OF COMPATIBILIZER TYPES AND LOADINGS ON THERMO-MECHANICAL PROPERTIES

This research was carried out to investigate the addition of grafted copolymers of maleic anhydride grafted-polylactic acid (PLAg-MA) and maleic anhydride grafted-natural rubber (NR-g-MA) on the mechanical and thermal properties of polylactic acid/ liquid natural rubber (PLA/LNR) blends. Prior to blend preparation, the PLA-g-MA and NR-g-MA were the first selfsynthesized by mixing maleic anhydride (MA) and dicumyl peroxide (DCP) which acted as initiator with the PLA and natural rubber (NR), respectively. The PLA/LNR, PLA/LNR/PLA-g-MA and PLA/LNR/NR-g-MA blends were prepared via meltblending method. The loading of PLA-g-MA and NR-g-MA was varied between 5, 10 and 15%, respectively. By comparing to the control sample (neat PLA/LNR blend), the addition of PLA-g-MA with 5 and 10% led to increment in tensile strength up to 22 MPa, whereas NR-g-MA promoted a negative trend of tensile properties to the blends. Differential scanning calorimetry (DSC) and thermogravimetry analysis (TGA) results showed the enhanced thermal stability for PLA/LNR/PLA-g-MA blend. Fourier transform infrared (FTIR) analysis confirmed the chemical interaction between the PLA and NR components where the grafted copolymers were successfully grafted onto PLA backbone and bonded with NR.