Polylactic acid (PLA) and polycaprolactone (PCL) are both biocompatible and biodegradable aliphatic polyesters, and their composite nanofibers have great application potential in biomedicine, filtration materials, and other fields. Solution homogenization is a crucial step in the preparation of high-performance PLA/PCL nanofibers, directly determining the fiber morphological uniformity, structural stability, and functional performance, and playing a decisive role in subsequent processing and application effects.
The core objective of PLA/PCL solution homogenization is to eliminate polymer agglomeration, achieve microscopically uniform dispersion of components, and simultaneously regulate the solution rheological properties to adapt to subsequent processes such as spinning. Due to the differences in polarity and crystallinity between PLA and PCL, simple physical mixing easily leads to phase separation, requiring a combination of multiple techniques to optimize the homogenization effect. Among conventional physical methods, ultrasonic treatment and mechanical stirring are widely used, breaking agglomerates through high-frequency vibration and shear force; however, improper parameter control can easily lead to polymer chain breakage, affecting the fiber's mechanical properties.
In advanced homogenization technologies, microfluidics, with its precise fluid control capabilities, achieves efficient mixing of polylactic acid (PLA)/polycaprolactone (PCL) solutions at the microscale. By controlling the fluid velocity and distribution within microchannels, laminar diffusion and shearing promote component fusion, effectively preventing aggregate regeneration and significantly improving solution homogeneity. High-pressure microjets utilize shear forces, collision forces, and cavitation effects under high pressure to achieve polymer molecular-level dispersion. After multiple cycles, composite solutions with narrow particle size distributions and excellent stability can be prepared, laying the foundation for spinning smooth, bead-free nanofibers.
The homogenization effect is influenced by multiple factors, with polymer ratios and molecular weight being key parameters. A high PLA content ratio improves component compatibility and reduces phase separation, while increasing the molecular weight of PCL enhances solution toughness; combined with homogenization, this improves fiber forming quality. Solvent selection must balance solubility and evaporation rate; adjusting the ratio of mixed solvents optimizes solution viscosity and conductivity, synergistically enhancing fiber homogeneity through homogenization. Furthermore, the homogenization temperature and time need to be precisely controlled to avoid polymer degradation due to high temperatures, while ensuring sufficient processing time to completely break up agglomerates.
Optimization of homogenization technology provides support for the functional expansion of polylactic acid/polycaprolactone nanofibers. In the biomedical field, homogenized solutions can be spun into tissue engineering scaffolds with uniform structures, promoting cell adhesion and proliferation; in the filtration field, homogenization treatment can improve the regularity of the pore structure of fiber mats, enhancing filtration efficiency. In the future, by combining pretreatment technologies with novel homogenization methods to further optimize solution dispersion stability, the large-scale application of polylactic acid/polycaprolactone nanofibers in high-end functional materials will be promoted.
