High Oxygen Barrier Property of Poly(propylene carbonate)/Polyethylene Glycol Nanocomposites with Low Loading of Cellulose Nanocrytals

Bionanocomposites of poly(propylene carbonate) (PPC) enhanced by cellulose nanocrytals (CNCs) are prepared via a two-step process using polyethylene glycol (PEG) as a carrier. Interfacial interaction among PPC, PEG, and CNCs, dispersion of CNCs in bionanocomposites, thermal properties, mechanical behavior, oxygen barrier property, and rheological responses are investigated. The obtained PPC/PEG/CNC nanocomposites display obvious improvement of barrier properties by adding an extremely low loading of CNCs. 02 permeability is decreased by more than 76% at CNC loading of 0.3 wt %. The Cussler model works better to predict gas barrier for nanocomposites. TEM results show that CNC is well dispersed in the matrix, and the introduction of CNC remarkably increases the tensile strength and storage modulus of PPC. Interestingly, elongation at break of the PPC/PEG/CNC nanocomposite remains above 580%. Moreover, the inclusion of CNCs increases the thermal stability and initial decomposition temperature (T-5%) of nanocomposites. The T-5% for the PPC/PEG/0.7CNC nanocomposite is approximately 246.5 degrees C, which is increased by 17.1% compared with that of pure PPC (210.5 degrees C). This makes PPC/PEG/CNC nanocomposites a very promising degradable material for food packaging applications.