The Development of TiO2 / PBS Composite Material by Thermal Spraying

Abstract

Abstract TiO2 coatings were prepared on polybutylene succinate (PBS) plastic by plasma spraying and High Velocity Oxygen Fuel (HVOF) spraying using agglomerated sub-micron TiO2 powder (200nm). Since PBS is well known material as bio-degradable plastic, the photo-catalytic TiO2/bio-degradable PBS composite material will exhibit purification of air and water without environmental damage. It was found that TiO2 agglomerated powders could be injected into PBS surface and anatase ratio greater than 60% could be achieved by 1pass plasma spraying. The anatase phase ratio decreased gradually with increasing pass count. By finding out adequate plasma spraying condition as a result of many experiments, TiO2/PBS composite material could be formed without large damage of PBS substrate. HVOF spraying could also provide TiO2 coating of 100% anatase ratio on PBS for 1~6 pass spraying. This means that 200nm agglomerated powders showed lower susceptibility to heat effect from gas flame and provided higher photo-catalytic activity as compared to plasma sprayed coatings. These coatings showed photo-catalytic degradation of 100ppm gaseous acetaldehyde (CH3CHO). As a result of photo-catalytic experiments, TiO2 coating formed by HVOF spraying showed a higher degradation rate because of higher anatase ratio. It means that 100ppm gaseous acetaldehyde was decomposed to less than 5 ppm after 7.2ks. Thermal spraying on PBS plastic in this investigation could imply both new application of thermal spraying and new possibilities of surface modification of low-melting point plastic.