In the current research, we are committed to solving the irreconcilable contradiction between fragmentation, agglomeration, poor size controllability, and high solid content in the preparation of BiOCl crystals. Water soluble block polymer polyethylene glycol monomethyl ether-b-polydimethylaminoethyl methacrylate (mPEG-b-PDMAEMA) was synthesized as dispersant to achieve high solid content by reducing the frequency of crystal collisions to avoid crystal fragments and agglomerates. With the reaction temperature of 80 °C, urea dosage of 40 g, bismuth salt solution addition rate of 0.45 ml/min, and variable amount of pre-added HCl in the reaction vessel, fragment-free BiOCl crystals of wide size ranges were successfully obtained with record-high solid content of above 10 wt%. Furthermore, bio-based pearlescent coatings were prepared by using as-synthesized BiOCl crystals as pearlescent pigments and polyglyceryl tetrastearate and polyphenyl polymethylene polyisocyanate (PAPI) as the formulations of two-component solvent free polyurethane . The decorative polyurethane coatings demonstrated excellent physical properties and corrosion resistance , which exhibited eye-catching gloss effects from pearl luster, glitter pearl luster, to shimmering luster derived from the size variation of 20, 50, and 70 µm, respectively. The large-scaled production of size controllable BiOCl crystals with high solid content in wide size range promises the practical applications in decorative coatings, cosmetics, clothing accessories, and car interior accessories.
Ming Liu,Guoqiang Shao,Pengpeng Lv,Jun Li,Qingshan Zhu
Two critical parameters: Glossiness and chromaticity space of pearlescent pigments were evaluated based on crystallinity and grain size. Both the roughness and the vertical distance evolution along the surface of deposited TiO 2 film are affected by the crystallinity. The optimal crystallinity of TiO 2 was deposited at the temperature of 350 °C. The TiCl 4 concentration effectively changed the grain size. However, the high flow rate of fluidizing gas and optimal gas–solid ratio (<0.11 m 3 /(kg h)) restricted the change of TiCl 4 concentrations in fluidized bed reactor . In this case, the grain size of the deposited TiO 2 film was about 55 nm. Depending on the grain size, the color of pearlescent pigments was adjusted by controlling the film thickness based on TiO 2 concentration. Finally, the silver pearlescent pigment with high glossiness was prepared by chemical vapor deposition method in a fluidized bed reactor.
Ming Liu,Guoqiang Shao,Pengpeng Lv,Jun Li,Qingshan Zhu
The fluidization quality significantly affects the mass transfer and the deposition reaction, which determine the uniformity of deposited TiO 2 thin films on fluorophlogopite particles. It was found that the effective addition ratio of nano-TiO 2 particles is above 0.2 wt% to realize fluidization of fluorophlogopite particles. The addition of nano-TiO 2 particles leads to competitive deposition between free TiO 2 particles and fluorophlogopite particles, which decreased the coating rate of TiO 2 on fluorophlogopite particle. Besides, the existence of free TiO 2 particles on pearlescent pigment particles decreases the glossiness. The gas-solid ratio primarily determines the number of the free TiO 2 particles on pearlescent pigment particles. It was summarized that the optimal value of addition ratio of nano-TiO 2 is 0.4 wt% with the gas-solid ratio of ∼0.05 m 3 kg −1 h −1 to enhance the fluidization quality on the one hand, and to reduce the free TiO 2 particles on the other hand.
危险品化学品经营许可证（带存储）