EFFECT OF CHEMICAL MODIFICATION OF MULTIWALL CARBON NANOTUBES ON THE PROPERTIES OF POLY(LACTIC ACID) COMPOSITE FILMS: SYNTHESIS AND CHARACTERIZATION.

To enhance the properties of poly(lactic acid) (PLA) composite films, unmodified (MWCNT) and modified multiwall carbon nanotubes (MWCNT-COOH, MWCNT-OH, and MA-g-MWCNT) were incorporated into the polymer matrix followed by the solvent casting method. The success of the modification of MWCNT with maleic anhydride (MA) was verified by absorption transmission reflectance spectroscopy (ATR). The fabricated nanocomposite films were analyzed by Fourier transform infrared (FT-IR) spectroscopy, thermal analyses, atomic force microscopy (AFM), contact angle measurements, dynamic mechanical analysis (DMA), and electrical conductivity tests. ATR spectra showed that MA was covalently grafted to the surface of the MWCNT, which was well dispersed and homogenously incorporated in the PLA matrix. The results of the thermal degradation demonstrated that the degradation value of the film increased from 328.91℃ to 347℃ with the addition of 0.5 wt% MA-g-MWCNT. Additionally, the MWCNT-OH/PLA films illustrated strongly hydrophilic nature due to the -OH groups. The surface resistance of 3 wt% of the MWCNT-COOH/PLA nanocomposite film decreased from 2.56x10⁹ to 2.42x10³ Ω (by 10⁶ order). Therefore, the properties of PLA were increased with the addition of functionalized MWCNTs, which can be used for different applications such as biomedical, food packaging, and electronics. [ABSTRACT FROM AUTHOR]