Structure-related properties of bionanocomposites based on poly(lactic acid), cellulose nanocrystals and organic impact modifier

Poly (lactic acid) (PLA) as a leading biobased, biodegradable and biocompatible thermoplastic still faces important industrial problems such as a slow crystallization, low thermal stability, and low impact resistance. This problem is addressed by the addition of nucleation agents based on cellulose nanocrystals (CNCs) and lignin-coated cellulose nanocrystals (L-CNCs) to increase nucleation density, enhance higher crystallization rate and increase the thermal stability. However, the effectiveness of CNCs/L-CNCs incorporation strongly depends on the quality of the dispersion and distribution in non-polar PLA matrix. The two-step pre dispersion processes based on solution ultra-sonication/mechanical stirring and masterbatch preparation by melt mixing using an internal mixer has been used. An organic impact modifier masterbatch has been used to increase the impact toughness that depends on many extrinsic and intrinsic variables. Injection molding technology has been used to prepare final samples and these were characterized by means of structure-morphology investigation, thermal and impact properties evaluation.