Sprecher
Beschreibung
Poly(2,6-dimethyl-1,4-phenylene oxide) (PPO) and syndiotactic polystyrene (sPS) are high-performance thermoplastics capable of forming co-crystalline (CC) phases with low-molecular-weight guest molecules. Upon guest removal, these materials transform into nanoporous crystalline (NC) structures that exhibit outstanding sorption properties toward gases and volatile organic compounds (VOCs)[1,2]. While the NC phases of sPS have been widely investigated for applications in purification, catalysis, and active packaging, recent studies have demonstrated that PPO-based NC forms possess lower density and enhanced sorption performance, governed by their crystallinity, morphology, and specific surface area[3,4].
In this work, PPO/atactic polystyrene (PPO/PS) fibers containing NC phases were prepared through guest-induced crystallization of melt-spun amorphous blends. Incorporation of atactic PS improves the processability of PPO by reducing the limitations associated with its high glass transition temperature. The resulting NC fibers exhibit faster sorption kinetics and higher VOC uptake than benchmark NC films, while their low pressure drop and high surface-to-volume ratio make them particularly attractive for purification technologies.
A liquid shear-driven processing route was also employed to fabricate PPO nanomaterials by shearing polymer solutions into a viscous, miscible medium, promoting antisolvent-induced precipitation. By tuning the polymer concentration and shear conditions, nanoribbons and nanofibers with either amorphous or NC morphologies were obtained. The NC nanostructures displayed significantly higher sorption capacities than their amorphous counterparts for representative water pollutants, including perchloroethylene, phenol, and atrazine. Moreover, shear-spun NC nanofibers outperformed conventional melt-spun fibers in pollutant uptake.
Finally, photocatalytic composites based on PPO-ZnO and PPO-g-C3N4/N-TiO2/ Y1.97SiO5:Ce0.03, fabricated using the same shear-driven approach, demonstrated efficient degradation of organic pollutants, including phenol, atrazine, and azo dyes such as Sunset Yellow and Acid Orange 7.
Overall, these findings highlight the potential of nanoporous crystalline polymer fibers and multifunctional photocatalytic composites as scalable platforms for the efficient sorption and degradation of pollutants, offering promising solutions for both water and air purification.
Reference
[1] C. Daniel, P. Antico, G. Guerra, Etched Fibers of Syndiotactic Polystyrene with Nanoporous-Crystalline Phases, Macromolecules 51 (2018) 6138–6148. https://doi.org/10.1021/acs.macromol.8b01044.
[2] C. Daniel, S. Longo, G. Fasano, J.G. Vitillo, G. Guerra, Nanoporous Crystalline Phases of Poly(2,6-Dimethyl-1,4-phenylene)oxide, Chem. Mater. 23 (2011) 3195–3200. https://doi.org/10.1021/cm200546r.
[3] A. Cozzolino, B. Nagendra, P. Rizzo, C. Daniel, G. Guerra, Fast uptake of organic pollutants from dilute aqueous solutions by nanoporous-crystalline PPO films with c-perpendicular orientation, Eur. Polym. J. 161 (2021) 110864.
[4] B. Nagendra, A. Cozzolino, C. Daniel, P. Rizzo, G. Guerra, High Surface Area Nanoporous-Crystalline Polymer Films, Macromolecules 55 (2022). https://doi.org/10.1021/acs.macromol.2c00271.