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Copolymer poly(D,L-lactide-co-glycolide) is used for obtaining the systems for controlled delivery of medicaments. Its specific characteristics make it suitable for various researches where its synthesis is performed in different ways. Using the system for controlled delivery of medicaments, an equal concentration of the medicament is achieved in the body throughout an extended period of time and it has advantages over the conventional methods. In this paper we present a new solvent/non-solvent chemical method for obtaining DLPLG nanospheres. In the experiment various stabilizers were used in order to examine their influence on morphological characteristics of DLPLG particles. The samples were characterized by Infrared Spectroscopy (IR), Differential Scanning Calorimetry (DSC), Scanning Electron Microscopy (SEM) and Stereological analysis.

Bentonite from the ‘Bogovina’ coal mine in Serbia, was characterized. The influence of acid treatment on its composition, as well as mathematical descriptions of this influence are reported. The purpose of this work was to correlate the concentration of the acid used for the treatment with the resulting bentonite composition. X-ray diffraction (XRD), infrared spectroscopy and quantitative chemical analysis were employed to define the changes caused by acid treatment. The contents of all the cations, except Si, decreased exponentially with increasing concentration of the HCl used for the treatment of the bentonite. This approach was tested on previously published data and was shown to be valid. The basal reflections of smectite decreased gradually and eventually disappeared after intense treatment, while the other reflections remained in the XRD patterns of all the samples, but decreased slightly with increasing acid strength. In addition, the amount of X-ray amorphous matter formed increased rapidly with increasing acid concentration up to 4.5 M. With further increase in the acid strength, the amount of X-ray amorphous matter remained virtually constant.

In this paper we report the results on synthesis of a composite biomaterial based on biphasic calcium phosphate (BCP) and poly-(DL-lactide-co-glycolide) (DLPLG). Besides, we have investigated the influence of new synthesis method on the structure and characteristics of the composite. The synthesis of biphasic calcium phosphate from Ca(NO3)2 x 4H2O and (NH4)3 PO4 in alkali environment was performed by means of precipitation technique. Composite material BCP/DLPLG was first prepared from commercial granules using chemical methods. Powdered polymer DLPLG was then homogenized at appropriate ratio with addition of biphasic calcium phosphate into the suspension. All samples were characterized by DSC, IR, X-Ray and SEM techniques.

The aim of this paper was the investigation of the influence of synthesis parameters, as well as the order of synthesis steps, in procedure of chemical precipitation, on the properties of synthesized nickel precursor. The starting materials were always the same aqueous solutions of Ni(NO3)2×6H2O and Mg(NO3)2×6H2O of constant molar ratio, 2% solution of SiO2 in the form of sodium silicate solution (module SiO2/Na2O = 3.0) and 10% solution of Na2CO3, while synthesis steps and addition modes were varied. Complete pH and temperature monitoring was performed during entire synthesis at 90°C. The formed precipitate aged 30 minutes at synthesis temperature. By changing the order and conditions of adding SiO2 and Na2CO3 solutions and keeping the treatment of precipitates the same (rinsing with hot distilled water followed by drying at 110°C for 24 hours) six different precursors were obtained. Samples characterizations were performed using different experimental techniques: XRD analysis, IR spectroscopy, reflection spectroscopy, TG analysis, N2 physisorption. The relation between synthesis procedure and precursor properties was established.

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In the paper ‘The influence of acid treatment on the composition of bentonite’ from Clays and Clay Minerals, vol. 54(2006), 699–704, by A. Vulković et al., in the list of authors, please replace Aleksandra Milutinović with Aleksandra Milutinović-Nikolić.