Multi-walled carbon nanotube reinforced poly (l-lactic acid) nanocomposites enhanced by water-crosslinking reaction

The preparation of multi-walled carbon nanotube (MWCNT)/poly (l-lactic acid) (PLLA) composites is described. Water-crosslinking technique was adopted to improve the physical characteristics of the nanocomposites. X-ray diffraction results showed that the crystalline of PLLA can be transformed to a natural poly(lactic acid) semicrystalline after water-crosslinking reaction. From differential scanning calorimeter (DSC) study, PLLA crystallization temperature decreases as the increasing of water-crosslinking time. High heat deflection temperature (HDT) of nanocomposite can be achieved at a low carbon nanotube loading and under water-crosslinking reaction. The HDT of PLA was raised from 62 to 106 °C when 1 phr MWCNT was added to PLLA. The composite after water-crosslinking treatment had exhibited better mechanical properties than the non-crosslinked composite because of strong chemical intra-molecular bonding. Also from thermogravimetric analysis (TGA) study, the thermal degradation temperature of the nanocomposite increases with the increasing of water-crosslinking time.