Enhanced Mechanical Properties of Poly(butylene adipate-co-terephthalate)/Cellulose Nanocrystal Nanocomposites Obtained by In Situ Polymerization

Biodegradable plastic films, in which poly(butylene adipate-co-terephthalate) (PBAT) is a major component, play a significant role in the expansion of the sustainable plastic packaging market. Unfortunately, biodegradable films tear easily. To garner consumer attention, it is paramount that these materials not only offer sustainability benefits but also provide durability. To enhance the mechanical properties of PBAT, an in situ method that polymerizes monomers upon the addition of aqueous cellulose nanocrystal (CNC) suspensions was developed herein to directly synthesize all-organic nanocomposites. The prepared films (containing only 0.05 wt % of CNC relative to the total amount of monomers) exhibited the highest tensile strength (71 MPa) and elongation at break (1018%) reported thus far for PBAT-based composites. The composite films were processed facilely through a blown extrusion process that is suitable for mass production, and a 22% improvement in tear toughness was achieved in relation to that of neat PBAT. The composite was completely decomposed into CO2 and water under composting conditions, exhibiting excellent biodegradability. This biodegradable PBAT/CNC nanocomposite with simultaneous improvements in tensile and tear resistance properties is expected to positively contribute to the expansion of the biodegradable plastics market.