Advanced Characterization of Silica–Encapsulated Aluminum Pigments

For environmental reasons, the paints industry shifts from solvent-borne towards water-borne formulations. This change is challenging the business of aluminum pigments, as the hydrogen released by the reaction of aluminum with water degrades the optical properties, besides being a safety concern. In this work, industrial-grade aluminum pigments are encapsulated, by a well-known method, in a silica matrix by sol-gel process using isopropanol - a more suitable solvent for the industry. The effectiveness of the encapsulation process is proven by advanced physical methods (Scanning Electron Microscopy, Energy Dispersive X-Ray Analysis, Selected Area Electron Diffraction, Fourier Transformed InfraRed Spectroscopy, Thermo-Gravimetric Analysis) and by industry-relevant tests (stability in water, hiding power, flop and granulometry). Moreover, advanced surface-applied physical methods (High Resolution Transmission Electron Microscopy combined with Selected Area Electron Diffraction and Scanning Transmission Electron Microscopy, and FT-IR microscopy) clearly show the homogeneity of the resulting pigments, a quality which is highly desirable for practical applications. The results demonstrate that stability comparable to that of pigments passivized by chromium-based inhibitors is easily achieved, for a variety of operating conditions. However, accomplishing a homogeneous silica layer of the right thickness is the determining factor for good optical properties

Collagen/Hydroxyapatite Composite Supports for Bone Tissue Engineering

Extended Abstract Controlled release systems are particularly used in medical applications due to reduced systemic toxicity In this study the synthesis and characterization of collagen/hydroxyapatite drug delivery systems (COLL/HA/active agent -COLL/HA-AAg) is presented. Four active components were used: acetylsalicylic acid, salicylic acid, acetaminophen and niflumic acid in order to use them in pain or inflammation management. The purpose of the use of these active agents is derived from the high risk of inflammation and pain that occurs upon the surgical intervention. Hydroxyapatite was obtained by precipitation using Ca(OH) 2 and NaH 2 PO 4 as precursors. By short, the COLL/HA composite material was obtained by the two steps mineralization process In order to determine the structure and morphology of the multifunctional materials, the COLL/HA/AAg drug delivery systems were investigated by Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD) and scanning electron microscopy (SEM). The delivery profile of the active agents was studied by monitoring the conductivity of the solution as well as by UV-VIS spectroscopy and are essential in the pain and inflammation management after the surgical intervention associated with the grafting. All the delivery studies were carried out in PBS (phosphate buffer saline solution at 37± 1°C