Study of TPU/TiO₂ and TPU/SiO₂ self‐cleaning composites based on selective laser sintering

Abstract In this paper, commercially pure thermoplastic polyurethane (TPU) powder with photocatalytic filler titanium dioxide (TiO₂) and low surface energy filler silicon dioxide (SiO₂) as composite powders was used to prepare TPU/TiO₂ and TPU/SiO₂ self‐cleaning composites, using selective laser sintering (SLS) technology. The effects of TiO₂ and SiO₂ fillers on the leveling and sintering properties of TPU lay‐up powder, as well as on the self‐cleaning and other properties of TPU parts were investigated. The results show that the addition of TiO₂ and SiO₂ fillers had a small effect on the leveling of TPU composite powders, sintering windows, and the dimensional accuracy and density of TPU parts, etc. The addition of TiO₂ and SiO₂ filler increased the surface roughness of TPU parts, the water contact angle from 123.82° of pure TPU to 140.25° of TPU/20TiO₂. As a result, the surface of the TPU surface water droplets easily formed a near‐spherical shape with the pollutants rolled off. The addition of TiO₂ gave TPU parts photocatalytic performance, which could decompose organic pollutants on the surface. TiO₂ and SiO₂ gave TPU parts self‐cleaning performance through the above mechanism. After the addition of TiO₂ and SiO₂, the thermal stability of TPU parts was improved, and the mechanical properties were slightly decreased. Highlights TPUs with both hydrophobic and photocatalytic properties are prepared by SLS technology. The addition of TiO₂ and SiO₂ has little effect on the process performance of SLS. Improvement of thermal stability and a slight decrease in mechanical properties of TPU parts.