Evaluation of the formed interface in biodegradable poly(l-lactic acid)/graphene oxide nanocomposites and the effect of nanofillers on mechanical and thermal properties

• The microstructure and thermal properties of PLLA-based nanocomposites with GO and org-GO have been evaluated and studied.
• org-GO has better dispersion than GO into PLLA.
• Both nanofilers enhance PLLA crystallinity but the org-GO showed higher nucleation activity.
• Dielectric relaxation spectroscopy showed that polymer chains in the nanocomposites have highly reduced mobility.

Graphene oxide (GO) and graphene oxide modified with dodekylamine (org-GO) were combined with poly(l-lactic acid) (PLLA) to prepare new nanocomposites. WAXD patterns showed that in nanocomposites the GO and org-GO was exfoliated, as the characteristic peaks of the filler totally disappeared. Thermal behavior of the nanocomposites was studied with DSC and compared to that of the neat PLLA. Acceleration of crystallization was observed under isothermal or non-isothermal conditions. The org-GO showed enhanced nucleation activity, resulting in faster crystallization rates in the respective nanocomposites. No substantial change in the glass transition temperature was observed, but a lower increase in heat capacity was found in nanocomposites, in good correlation with a lower dielectric strength of the segmental relaxation associated with the glass transition. Biodegradation rates were enhanced in nanocomposites.

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