Bucharest, Romania


Bucharest, Romania
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Dima S.-O.,INCDCP ICECHIM | Panaitescu D.-M.,INCDCP ICECHIM | Orban C.,Science Corax Bioner CEU S.A. | Ghiurea M.,INCDCP ICECHIM | And 8 more authors.
Polymers | Year: 2017

We focused on preparing cellulose nanofibrils by purification, separation, and mechanical treatment of Kombucha membranes (KM) resulted as secondary product from beverage production by fermentation of tea broth with symbiotic culture of bacteria and yeast (SCOBY). We purified KM using two alkaline solutions, 1 and 4 M NaOH, which afterwards were subjected to various mechanical treatments. Transmission electron microscopy (TEM), scanning electron microscopy (SEM), dynamic light scattering (DLS), X-ray diffraction (XRD), X-ray fluorescence (XRF), Fourier-transform infrared spectroscopy (FTIR), and thermogravimetric analysis (TGA) were employed to evaluate the purification degree, the size and aspect of cellulose fibrils after each treatment step, the physical-chemical properties of intermediary and final product, and for comparison with micro-crystalline cellulose from wooden sources. We determined that 1 M NaOH solution leads to approx. 85% purification, while a higher concentration assures almost 97% impurities removal. XRD analysis evidenced an increase in crystallinity from 37% to 87% after purification, the characteristic diffractograms of Iα and Iβ cellulose allomorphs, and a further decrease in crystallinity to 46% after microfluidization, fact correlated with a drastically decrease in fibrils' size. FTIR analysis evidenced the appearance of new chain ends by specific transmission bands at 2941 and 2843 cm-1. © 2017 by the authors.

Rapa M.,Science ICPAO SA Medias | Ghioca P.N.,INCDCP ICECHIM | Grosu E.,Science ICPAO SA Medias | Iancu L.,INCDCP ICECHIM | And 4 more authors.
Journal of Optoelectronics and Advanced Materials | Year: 2013

Polypropylene (PP) is a thermoplastic polymer used as packaging for alcoholic and nonalcoholic beverages bottles, detergent and cosmetics, bags, transparent packaging for food and non-food industrial products, pipes, fittings and other applications. In this paper, wastes of PP resulted from textile cones were modified with poly (styrene-isoprene-styrene) (SIS). Recycled PP/SIS composites containing 0, 5, 10, 15, 20, 25 and 30 weight % of SIS were performed by melt alloying technique. By varying of SIS content can be tailored composites able to meet the service requirements when PP is used as recycled materials for specific end use applications. It is found that new developed composites show a good elasticity and notched impact IZOD compared with unmodified PP wastes and are suitable for industry field, e.g. automotive parts.

Sandu T.,Polytechnic University of Bucharest | Sarbu A.,INCDCP ICECHIM | Constantin F.,Polytechnic University of Bucharest | Ocnaru E.,INCDCP ICECHIM | And 3 more authors.
Revue Roumaine de Chimie | Year: 2011

Polypyrrole (PPY) was functionalized by reaction with glutardialdehyde using sulphuric acid as catalyst. The samples of functionalized polypyrrole were then used for the covalent immobilization of polyphenol oxidase. The surface elemental composition of this enzyme was determined by X-ray Photoelectron Spectroscopy. FTIR spectrometry, Raman spectroscopy, Scanning Electron Microscopy and X-Ray Diffraction were used to prove polypyrrole functionalization and the immobilization of this enzyme.

Cardei P.,National Institute of Research Development for Machines | Popa N.,Polytechnic University of Bucharest | Voicu G.,Polytechnic University of Bucharest | Minciuna V.-S.,Polytechnic University of Bucharest | And 4 more authors.
Materiale Plastice | Year: 2015

The paper presents the results obtained by the authors for the mathematical modeling of the mechanical behaviour variation of the composite material with polymeric or elastomeric matrix and reinforced with protein fibers (CFP), depending on the concentration of the reinforced material. The mathematical model of the main mechanical properties of a composite material allows optimal approximation variants of material that is as close to that required in a particular field. The method proposed in this article is generally applied to the composite materials and is valid not only for the case of mechanical properties dependence of a single parameter (the concentration of a constituent) but in the case of dependence on several parameters, case in which the possibilities of achieving a favourable variant are much larger and more accurate. In the category of free parameters of the mathematical model can enter all the constituents' concentrations, but, in addition, also important are the technological parameters: temperature in the manufacturing process, the reinforced material granulation, the degree of stirring, pressure, etc.

Hutanu F.,Stefan Cel Mare University of Suceava | Doni M.B.,INCDCP ICECHIM | Munteanu C.,Institute of Physical Chemistry Ilie Murgulescu | Petrescu S.,Institute of Physical Chemistry Ilie Murgulescu | Marcu M.,Institute of Physical Chemistry Ilie Murgulescu
Revista de Chimie | Year: 2014

In this article is reported the effect of anionic surfactants AOT (dioctyl sulfosuccinate) in the electrodeposition of Prussian Blue (PB) onto screen-printed carbon electrodes (SPCE). The SPCE/PB/AOT electrode displayed a significant improvement of its electrochemical properties and of its stability compared with PB modified SPCE formed in absence of surfactant. The effects of AOT concentration and applied potential on the sensor response to H 2O2 are discussed. The PB film stabilized with AOT, were characterized by Scanning electron microscopy (SEM), and Raman spectroscopy. The new electrodeposed PB/AOT film proved excellent electroanalytic properties for H2O2 determination and is a promising material for assembling biosensors based on oxidoreductase enzymes.

Popa N.,Polytechnic University of Bucharest | Cardei P.,National Insti. of Res. Devel. for Machi. | Voicu G.,Polytechnic University of Bucharest | Minciuna V.-S.,Polytechnic University of Bucharest | And 3 more authors.
Materiale Plastice | Year: 2015

The paper presents the results obtained by the authors in the research of the mechanical behaviour variation of the polymeric reinforced with protein fibers composite (CFP) depending on the reinforcing material concentration in the elastomeric matrix. The determination of the mechanical behavior variation depending on the reinforcing material concentration is important not only to establish a convenient concentration to obtain some mechanical properties required in any field of application, but for obtaining an optimal method of choice of some values in its concentration, so that the composite material to satisfy a certain property (value) or even a number of mechanical properties.

Staicu A.,Romanian National Institute for Lasers, Plasma and Radiation Physics | Pascu A.,Romanian National Institute for Lasers, Plasma and Radiation Physics | Nuta A.,INCDCP ICECHIM | Sorescu A.,INCDCP ICECHIM | And 3 more authors.
Romanian Reports in Physics | Year: 2013

A short description of the photodynamic therapy as an alternative cancer treatment procedure is made, highlighting the role of the photo sensitizer and of the basic molecular processes resulting in active species. The synthesis path of metal lasted phthalocyanine photo sensitizers used in this paper are presented and analyzed, considering the conventional and the microwave assisted procedures. Measurements are reported of some specific photo physical quantities characterizing the active species generation and properties (lifetime and quantum yield), when they are photo generated by the synthesized compounds. The dedicated experimental set-ups are described. Comparative measured data of the mentioned photo physical quantities of the synthesized phthalocyanines are presented.

Sandu T.,Polytechnic University of Bucharest | Sarbu A.,INCDCP ICECHIM | Garea S.A.,Polytechnic University of Bucharest | Iovu H.,Polytechnic University of Bucharest
UPB Scientific Bulletin, Series B: Chemistry and Materials Science | Year: 2011

The polypyrrole was functionalized by reaction with glutardialdehyde in order to insert further binding sites on the polymer surface for covalent immobilization of enzymes. Five parameters of functionalization reaction were studied: the catalyst (sulphuric acid) concentration, glutardialdehyde/water ratio, polypyrrole/functionalization solution ratio, temperature and time. The effect of each parameter was determined by keeping the other four constant. The samples were analyzed by chemical methods and Fourrier Transform Infrared Spectroscopy.

Rapa M.,Science ICPAO S.A. | Grosu E.,Science ICPAO S.A. | Ghioca P.N.,INCDCP ICECHIM | Iancu L.,INCDCP ICECHIM | And 4 more authors.
Materiale Plastice | Year: 2016

This investigation concerns the preparation of binary PPR/SEBS and PPR/SBS blends by melt mixing procedure with the goal of studying the effect of thermoplastic elastomers on performance of polypropylene random copolymer (PPR) in the extrusion and injection molding processes. Effect of poly[styrene-b-(ethylene-cobutylene)-b-styrene] (SEBS) and poly(styrene-b-butadiene-b-styrene) (SBS) respectively on the mechanical and thermal properties of PPR have been investigated. The melt processability, melt flow index (MFI), tensile properties, VICAT softening temperature (VST), heat deflection temperature (HDT), Shore hardness and IZOD measurements highlighted that SEBS is more efficient than SBS.

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