alfa-costic acid, a plant sesquiterpenoid from Dittrichia viscosa, as modifier of Poly (lactic acid) properties: a novel exploitation of the autochthone biomass metabolite for a wholly biodegradable system

In this work, alfa-costic acid (alfa-CA), a metabolite coming from a perennial autochthon shrubDittrichia viscose, was used as natural additive of polylactic acid (PLA), a biodegradablethermoplastic polymer, in order to modulate its chemico-physical properties, for the achievementof a wholly biobased packaging system. It's the first time that ??costic acid is exploited for thisappealing and novel application. The investigations performed on PLA/?-CA films, evidencedstrong physical interaction occurring between the polymer and ?-CA, as confirmed by NMR andFTIR-ATR analyses; SEM micrographs showed a good embedding of ?-CA particles inside PLApolymer matrix; GPC analysis highlighted a slight hydrolysis of polymer matrix clearlyevidenced in mechanical properties. DSC analysis underlined the significant decreasing of Tg,associated with the increase of PLA chain mobility. TGA thermograms evidenced one broaddegradation profile of PLA/?-CA system, accounting for the weighty physical interactionoccurring between the polar groups of both polymer and plasticizer. Finally, PLA surfacewettability notably enhanced by the inclusion of ?-CA polar groups. In conclusion, ?-CA can beconsidered as a promising plasticizer of PLA and a worthy modifier of its overall properties.