Enhanced mechanical performance of poly(propylene carbonate) via hydrogen bonding interaction with o-lauroyl chitosan

Biodegradable poly(propylene carbonate) (PPC) was blended with o-lauroyl chitosan (OCS) by solution casting using chloroform as common solvent. FTIR and XPS confirmed hydrogen bonding interaction between PPC and OCS, which was saturated when OCS loading reached 20 wt%. Because of the hydrogen bonding interaction, a 2-3 °C increase in glass transition temperature and a 5% improvement (46-53 °C) in weight loss temperature (T5%) were observed in the PPC/OCS blend with OCS loading of 10-20 wt%. The interaction was beneficial to improving the mechanical performance of PPC. The tensile strength, elongation at break, and Young's modulus of the pure PPC film were 31 MPa, 3.8%, and 392 MPa, respectively. For the blend with 10 wt% OCS loading, the effect of toughening was so substantial that the maximum elongation at break increased twofold to 8.1% and Young's modulus increased nearly threefold to 1014 MPa; the tensile strength and stress at break remained unchanged.