Synthesis and Evaluation of Potassium Hexatitanate Fibers with Negligible Leachability

Abstract

A conversion process from potassium tetratitanate fibers into potassium hexatitanate was investigated to develop potassium hexatitanate fibers with negligible leachability which are usable as a filler for fiber-rein-forced polyester thermoplastic resins. Calcined potassium tetratitanate fibers were dispersed in water. By titrating the above mentioned suspension with an aqueous HCI solution to adjust the value of ([K+]/[H3O+])2/3=5.71×105 at 60°C, the fibers with TiO2/K2O=5.95 was obtained. The product thus obtained was heated at 1000°C for 30min, then potassium hexatitanate fibers having a tunnel structure were obtained. Then, the water soluble potassium was further removed with an aqueous HCI solution. Potassium hexatitanate fibers having a tunnel structure whose molar ratio of TiO2/K2O was 6.0 was obtainable. Water soluble potassium thus prepared was only 4 mass ppm. The potassium hexatitanate fibers prepared by the novel method developed by the present authors were found useful as a reinforcing material for polycarbonate which has been known to be vulnerable to soluble potassium.