Impact of Processing Methods on Mechanical Properties of Neat PLA and PLA Blends with PCL and PEO: Electrospinning vs Solvent Casting

The increasing environmental concerns related to no-biodegradable plastics have driven the development of biodegradable alternatives derived from renewable resources. Polylactic acid (PLA), a biodegradable polymer known for its favorable mechanical strength and biocompatibility, suffers from brittleness and poor ductility. This study aims to improve the flexibility of PLA by blending it with polycaprolactone (PCL) and polyethylene oxide (PEO). Specifically, thin films were fabricated from neat PLA, PCL, PLA/PCL, and PLA/PEO blends using both electrospinning and solvent casting to investigate the effects of processing methods on their mechanical behavior. The films were characterized using SEM, FTIR, XRD, DSC, uniaxial tensile testing, and water contact angle measurements. The surface morphology of single electrospun fibers was further examined using AFM. We found that electrospun PLA films exhibited higher elongation at break and ultimate strength with a slightly lower Young’s modulus in comparison to its solvent-cast films. FTIR, XRD, and DSC analyses consistently showed that the electrospun PLA films had significantly lower crystallinity compared to their solvent-cast counterparts. Notably, AFM phase imaging revealed that the electrospun PLA fibers exhibited an aligned crystalline structure. Blending PLA with PCL significantly improved elongation at break in electrospun films, which, unlike solvent-cast blends, retained a Young's modulus comparable to electrospun PLA. This improvement is likely due to reduced phase separation and enhanced crystalline alignment. Furthermore, electrospun films of neat PLA, PCL and PLA/PCL blends were more hydrophobic than their solvent-cast counterparts. Although PLA/PEO blends demonstrated enhanced surface hydrophilicity, they exhibited a marked reduction in mechanical properties. Overall, this study demonstrates that electrospinning effectively enhances the flexibility and mechanical performance of PLA-based films by mitigating the effects of poor miscibility in polymer blends and promoting molecular alignment. These findings suggest that electrospinning is a promising processing method for producing PLA-based films with enhanced flexibility and mechanical integrity, without the need for plasticizers or compatibilizers.