Influence of mechanochemical treatment on thermal and structural properties of silica–collagen and hydroxyapatite–collagen composites

Abstract

The paper presents the results of research on a series of composite materials based on hydroxyapatite, silica gel and collagen as biologically active substances. Their preparation was made using mechanical energy in accordance with the principles of "green chemistry". Mechanochemical treatment was conducted in a planetary mill with different rotations of milling (200 and 400 rpm) and various periods of time (30, 60 and 120 min). Temperature and pressure changes generated during the mechanochemical treatment were recorded. The obtained composites were analyzed using the low-temperature nitrogen adsorption/desorption method and thermal analysis (TG/DTA). Very interesting and promising results were obtained encouraging further research in this area.

Development of a New Ternary Al2O3–HAP–Pd Catalyst for Diethyl Ether and Ethylene Production Using the Preferential Dehydration of Ethanol

“…For all different catalysts except the bare HAP catalyst, their N 2 uptake increased sharply over the relative pressure ( P / P 0 ) of 0.5–0.9, due to the capillary condensation of N 2 within the uniform mesopores . In the corresponding high P / P 0 , the course of the isotherm is quite steep with respect to the pressure axis which indicates a large size of pores of cylindrical shape . Therefore, the hysteresis loop of the bare HAP catalyst at P / P 0 ≈ 0.9 in a wide range of pressures is horizontal which is due to the occurrence of slit pores .…”

“…30 In the corresponding high P/P 0 , the course of the isotherm is quite steep with respect to the pressure axis which indicates a large size of pores of cylindrical shape. 31 Therefore, the hysteresis loop of the bare HAP catalyst at P/P 0 ≈ 0.9 in a wide range of pressures is horizontal which is due to the occurrence of slit pores. 32 Furthermore, the obtained PSD curves confirm that the pore sizes were in the range of 2−50 nm assigned to the mesoporous structure.…”