Haijun Xu

Novel Ti _1-x Fe _x O ₂ pigments ( x =   0-0.2) were successfully synthesized via the sol-gel method. Fe³⁺ doping preserved the rutile phase structure of TiO ₂ while suppressing crystal growth; as the Fe content increased, the color of the pigments gradually transitioned from light red to deep red and further to reddish-brown. Among them, Ti _0.9 Fe _{0. 1} O ₂ calcined at 700 ℃ exhibited the optimal red hue ( a * =   25.7), while Ti _0.95 Fe _{0. 0 5} O ₂ treated at 800 ℃ demonstrated the best near-infrared reflectance performance (73.62 %). All samples showed notably higher reflectance in the NIR range compared to a commercial iron-oxide pigment of similar color (44.25 %). Furthermore, chromatic property tests after acid/alkali corrosion, together with thermogravimetric-differential scanning calorimetry analysis, confirmed the good chemical and thermal stability of this series of pigments. These energy-saving pigments show promising potential for application in high-efficiency energy-efficient building materials such as solar heat-reflective functional artificial stones.

Two types of polycarboxylate superplasticizers (PCEs) with β‐cyclodextrin (β‐CD) as pendant groups were synthesized by different methods to employ monovinyl β‐CD monomer (MA‐β‐CD), and their dispersion robustness toward clay was evaluated by the dosage to achieve the specific spread value of the cement paste in the presence of 3 wt% kaolin. The interaction mechanism was investigated by X‐ray diffraction analysis and adsorption measurement, and it was proposed that the sorption of PCEs on the surfaces of kaolin particles was weakened by β‐CD pendants due to their pronounced steric hindrance effect. The results demonstrated that PCE with higher contents of β‐CD pendants, which was synthesized via partially replacing poly(ethylene oxide) monomer by MA‐β‐CD, was more tolerant toward kaolin. POLYM. COMPOS., 39:755–761, 2018. © 2016 Society of Plastics Engineers