Investigation of the characteristics and performance of compatibilized PLA/PCL blends and their nanocomposites with nanocalcium carbonate

Abstract

This study examines the preparation and characterization of Poly lactic acid (PLA)/Poly(ε-caprolactone) (PCL) blends with the addition of glycidyl methacrylate (GMA) as a chain extender, as well as nanocomposites of compatibilized and uncompatibilized PLA/PCL with nanocalcium carbonate (NCC). The blend compositions included 2 and 3 phr of GMA, while the nanocomposites contained 7 and 9 phr of NCC. The samples were processed via melt mixing, and their crystallinity, tensile properties, morphology, permeability, migration, and rheology were analyzed. The addition of 3 phr of GMA and 9 phr of NCC resulted in a significant increase in the tensile modulus of the PLA/PCL (75/25) blend from 1800 MPa (for neat PLA) to 3400 MPa. AFM analysis revealed that GMA improved the barrier properties of the PLA/PCL nanocomposite by reducing the roughness of the material. Furthermore, GMA and NCC promoted a higher degree of network formation within the polymer blend, as evidenced by a 4.5% increase in gel content. The incorporation of 9 phr of NCC increased the crystallinity of the PLA/PCL blend from 1.2% to 4.85%, although this effect was mitigated when GMA was also present. Interestingly, the simultaneous use of GMA and NCC significantly reduced the total migration of the material, resulting in a weight loss percentage of only 1.2%, compared to samples containing only one additive. Ultimately, the oxygen permeability of the compatibilized nanocomposite with 9 phr of NCC was measured at 60 \((\frac{{\text{cm}}^{3}\text{mm}}{{\text{m}}^{2}\text{day atm}})\), a value comparable to that of commonly used oil-based polymers such as PE and PP.