Shigui Zhao

Antifouling agent 4, 5‐dichloro‐2‐n‐octyl‐4‐isothiazolin‐3‐one (DCOIT) in a one‐stage process based on the self‐catalytic reaction between methyl trimethoxysilane (MTMS) and 3‐aminopropyl trimethoxysilane (APS) in an aqueous system without any surfactants and catalysts have been developed. The optimal preparation process parameters of organosilica nanocapsules encapsulating DCOIT (DCOIT@SiNC) were determined using response surface methodology (RSM) based on the single‐factor experimental results. The results of RSM optimization showed that 49.51% encapsulation efficiency (EE [%]) would be achieved with a shell–core mass ratio of 5.59:1, a MTMS‐APS mole ratio of 1.52:1, and a reaction temperature of 31°C. DCOIT@SiNC prepared according to the RSM optimal process exhibited a decent uniform sphericity with an average particle diameter of 660.50 nm. The encapsulation was characterized by Fourier‐transform infrared and X‐ray diffraction. The loading efficiency and thermal stability were verified via thermogravimetric analysis. Compared to DCOIT, DCOIT@SiNC had better controlled release performance, and the release kinetics investigated by Riger‐peppas model indicated that the release of DCOIT was diffusion‐controlled.

To verify the feasibility of the determination of the SiH content (HC) of hydrogen silicone oil (HS‐oil) with Fourier transform near infrared (FT‐NIR) spectroscopy and attenuated total reflectance (ATR)–Fourier transform infrared (FTIR) spectroscopy combined with the partial least squares regression (PLS‐R) model, HS‐oil samples were synthesized from concentrated hydrosilicone oil (HC = 1.4 wt %), octamethylcyclotetrasiloxane, and hexamethyldisiloxane or prepared by the dilution of concentrated hydrosilicone oil with octamethylcyclotetrasiloxane. The FT‐NIR PLS‐R model (8695–4000 cm⁻¹, two principal components) was developed from the FT‐NIR spectral data, and the coefficient of determination for cross‐validation (R²) and the coefficient of determination for external validation (r²) were 0.992 and 0.995, respectively. The ATR–FTIR PLS‐R model (2302–2040 cm⁻¹, one principal component) was developed from the ATR–FTIR spectral data; it produced an R² of 0.995 and an r² of 0.996. This study demonstrated that the combination of FT‐NIR and ATR–FTIR spectroscopy with the PLS‐R model were successfully used to determine the HC of the HS‐oil. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014, 131, 40694.

To explore the synthesis condition of the bionic nano-silicon-substituted hydroxyapatite and the impact of the silicon content on its crystallization properties, hydroxyapatite of different silicon content were synthesized from Ca(NO3)2, (NH4)2HPO4 and Si(OCH2CH3)4(TEOS) via an aqueous precipitation reaction. Fourier transform infrared spectroscopy (FTIR), X-ray fluorescence spectrum (XRF), X-ray diffraction (XRD) and transmission electron microscopy (TEM) were used for hydroxyapatite characterization. The results show that relative low temperature (40¡䧠is conducive to obtain pure bionic nano-silicon-substituted hydroxyapatite. Under this condition, SiO4^4- enters the lattice of hydroxyapatite and replaces part of PO4^3-. The more the content of silicon is, the lower the crystallinity is, the smaller the grain size is and the higher the lattice parameters a and c are