Improving the UV Resistance and Service Life of Polystyrene-Based Building Materials via Low-Concentration Metal Complex Modifiers

PS is highly susceptible to UV-induced photodegradation, which results in deterioration of its mechanical and aesthetic properties. In the present study, four novel and highly aromatic levofloxacin metal complexes, synthesized from Zn, Sn, Cu, and Ni, were investigated as low-concentration (0.5% w/w) photostabilizer additives for PS. Composite films were prepared by solution casting and subjected to accelerated UV irradiation up to 300 hours. Photostabilizing performance was systematically followed by monitoring changes in the carbonyl index via FT-IR spectroscopy, mass loss measurements, and surface morphology analyses using SEM and AFM. Results showed that all levofloxacin metal complexes had a pronounced inhibition effect on the photodegradation of PS. The additives efficiently suppressed the generation of carbonyl groups, reduced the mass loss, and significantly minimized surface roughness and cracking in the case of pure PS films. This stabilization is considered to be dependent on the aromaticity of the complexes and their heteroatom content, most probably as a result of UV absorption and radical scavenging mechanisms. In this paper, novel levofloxacin metal complexes were established as efficient and promising photostabilizing additives that enhance the durability of polystyrene under UV exposure.