Effect of functionalized multiwalled carbon nanotubes on thermal stability of poly (L-LACTIDE) biodegradable polymer

The thermal stability of poly (l-lactide) plla biocompatible and biodegradable polymer reinforcedwith functionalized multiwalled carbon nanotubes (mwcnts) was investigated. for improvementof mwcnts, the pristine mwcnts (pmwcnts) were functionalized, at first, by friedel crafts acylation,which introduced the aromatic amine groups on the side wall of mwcnts (mwcnt-nh2) without shorteningor cutting of pmwcnts. then, the plla chains were covalently grafted from the sidewall ofmwcntnh2by in situ ring-opening polymerization of l-lactide oligomers (la), using stannous octanoate as theinitiating system (mwcnt-g-plla). the ft-ir and xps spectra revealed that the plla chains graftedstrongly from the sidewall of mwcnts. the thermo-gravimetric analysis of prepared composites withvarious concentrations of mwcnt-g-pllas shows a significant increment in the thermal stability of composites,by increasing the concentration of mwcnt-g-pllas in composites. the xrd analysis revealed thatthe mwcnt-g-pllas increased the crystallinity of plla, indicating that the composites with plla graftedmwcnts were more thermally stable than those of neat plla.