Digital Light-Processing (DLP) 3D Printing of Magnesium Phosphate Minerals and Cements

Digital light processing (DLP) enables the fabrication of complex 3D structures based on a photopolymerizable resin usually containing a photo initiator and an UV or photo absorber. The resin and thus the final properties of the printed structures can be adjusted by adding fillers like bioceramic powders relevant for bone-regeneration applications. Herein, a water-based and biocompatible poly(ethylene glycol diacrylate) (PEGDA) resin containing the photo initiator lithium-phenyl-2,4,6-trimethylbenzoylphosphinate (LAP) enables the production of 3D structures via DLP. The addition of calcium magnesium phosphate cement (CMPC) powder, acting as photo absorber, leads to higher accuracy of the final structures. After curing the printed construct in a diammonium–hydrogen phosphate (DAHP) bath for hardening, the resulting mechanical properties can be adjusted without post-process sintering. Solid loading of up to 40 wt% CMPC powder is possible, and the resins are investigated regarding their rheological behavior and printability. The resulting constructs are analyzed in respect to their surface morphology using scanning electron microscope (SEM), porosity, phase composition using X-ray diffraction (XRD) methods, as well as mechanical properties influenced by the hardening process using DAHP for different durations.     

Design,synthesis and potential use of 3,9-substituted xanthene handles for Solid Phase Peptide Synthesis

Theoretical calculations on different xanthene derivatives and related structures were performed and as a result conclusions could be drawn for the acid-lability of substituted xanthenes. (9-Hydroxyxanthene-3-oxy)acetic- and valeric acid ( 6a and 6b ) were selected, synthesized in a six-step route, and 6b was tested for its applicabiliy as a handle for solid phase synthesis of peptides.     

Application of sputtered ceramic TiC/a:C thin films with different structures by changing the deposition parameters

Titanium carbide-based thin films have been produced by DC magnetron sputtering. It was demonstrated that the same technology with changing of the deposition parameters, such as deposition temperature or power of Ti target, resulted in the preparation of TiC/a:C thin films with various structures. The structure of thin films and volume fraction of amorphous and crystal phases were precisely tailored by the control of deposition parameters. These ceramic nanocomposite TiC/a:C thin films according to their various structures, hence, their different mechanical, tribological, or wetting parameters can be used in wide range of applications.     

Eco-friendly preparation and structural characterization of calcium silicates derived from eggshell and silica gel

In this work, the preparation of calcium–silicate-based composites consisting of natural waste from calcium source as eggshell and silica gel from a desiccator as a silicon source both presenting alternative materials for cheap preparation of eco-friendly calcium–silicate bioceramics has been investigated. The effect of the CaO/SiO₂ ratio on microstructural properties has also been studied. The pseudowollastonite formation has been observed in the case of 40 wt.% CaO and 60 wt.% SiO₂ with lowest porosity and highest density 2.6 g/cm³. In the case of 50 wt.% CaO and 50 wt.% SiO₂, the phase transformation from pseudowollastonite to wollastonite was observed. Increasing the calcium content caused higher apparent porosity with 19%. It was shown that the development of novel ceramics from reused waste, eggshell, or silica can be an optimal solution for the low-cost preparation of calcium silicates with potential applications in medicine or cement, food industry.