Corncob is an agro-industrial waste available in large quantities in several countries, including Brazil,
which deserves to be better and/or properly used. This work evaluates the use of corncob as a source of
cellulose to obtain nanocrystals by acid hydrolysis in order to obtain a material suitable to be a reinforcement
agent in the manufacture of nanocomposites. The hydrolysis was performed at 45 ◦C for 30, 60 and
90 min, using 15 mL of H2SO4 (9.17 M) for each gram of cellulose. The resulting cellulose nanocrystals
of corncob (CNC) were characterized by crystallinity index, morphology and thermal stability, and their
reinforcing capability was evaluated using polyvinyl alcohol (PVA) as the polymeric matrix. Among the
hydrolysis conditions carried out, the extraction time of 60 min resulted in nanoparticles (CNC60) with
larger reinforcing capability. The CNC60 endowed the CNC/PVA composites with a significantly improved
tensile strength of 140.2% when only 9% (wt.%) CNC60 was incorporated. The CNC60 presented a needleshaped
nature, high crystallinity (83.7%), good thermal stability (around 185 ◦C), an average length (L) of
210.8
±
44.2 nm and a diameter (D) of 4.15
±
1.08 nm, giving an aspect ratio (L/D) of around 53.4
±
15.8.
The results show that the more suitable filler was CNC60. Since CNC60 has the highest crystallinity among
the CNC samples, but does not have the highest aspect ratio, these results suggest that the difference
in the crystallinity index has a greater influence on the tensile properties than the aspects ratio, in this
case. Cellulose nanocrystals obtained from corncob have great potential as reinforcing agents for the
manufacture of nanocomposites.