Romanian National Institute for Research and Development in Chemistry and Petrochemistry

Bucharest, Romania

Romanian National Institute for Research and Development in Chemistry and Petrochemistry

Bucharest, Romania
SEARCH FILTERS
Time filter
Source Type

Marin L.,Romanian National Institute for Research and Development in Chemistry and Petrochemistry | Topala P.,A.Russo State University
IOP Conference Series: Materials Science and Engineering | Year: 2017

The paper presents the results of experimental research on the physics of natural graphite film formation, the establishment of chemical composition and functional properties of the graphite films, formed on metal surfaces, as a result of the action of plasma in the air environment, at a normal pressure, under the electrical discharge in impulse conditions (EDI). The researchings were performed in the frame of doctoral thesis "Research on lessening of the bonding effects between the metallic and nonmetallic surfaces through the graphite films" and aimed to identify the phenomena that occur at the interface metal/ film of graphite, and to identify also the technological applications that it may have the surface treatment for submitting the films of graphite on metallic surfaces achieved through an innovative process of electrical pulsed discharges. After the research works from the PhD theme above mentioned, a number of interesting properties of graphite pellicle have been identified ie reducing of metal surface polarity. This led to drastic decreases for the values of adhesion when bonding of metal surfaces was performed using a structural polyurethane adhesive designed by ICECHIM. Following the thermo-gravimetric analysis, performed of the graphite film obtained by process of electrical pulsed discharges, have been also discovered other interesting properties for this, ie reversible mass additions at specific values of the working temperature Chemical and scanning electron microscopy analysis have revealed that on the metallic surface subjected to electrical pulsed discharges process, outside the graphite film, it is also obtained a series of spatial formation composed of carbon atoms fullerenes type which are responsible for the phenomenon of addition of mass. © Published under licence by IOP Publishing Ltd.


Badescu V.,Romanian National Institute for Research and Development in Chemistry and Petrochemistry
Revue Roumaine de Chimie | Year: 2015

(Graph Presented) The aim of this article in continuation of Part I is the study of the fragmentation reactions of tetraethoxysilane (TEOS) as a precursor in the sol-gel process initiated by electronic impact in the ionization chamber of a double focusing mass spectrometer. In Part I the primary fragmentation ions at masses 207, 193, 179 and 163 were obtained experimentally by B/E linked scan by radical induced fragmentation reactions. In Part II eliminations of neutral fragments from the primary ions and the obtained ions by consecutive elimination reactions were evidenced experimentally by the B/E and B/E(1-E)1/2 linked scans. On this basis charge induced reactions with eliminations of acetaldehyde, ethylene and hydrogen are presented. The existence of fragmentation ions thus obtained is supplementary argued by measuring the ion masses at high resolution and the M+1, M+2 isotopic effects and by the calculation of the double bond equivalent (DBE).


Frone A.N.,Romanian National Institute for Research and Development in Chemistry and Petrochemistry | Berlioz S.,University of Toulon | Chailan J.-F.,University of Toulon | Panaitescu D.M.,Romanian National Institute for Research and Development in Chemistry and Petrochemistry
Carbohydrate Polymers | Year: 2013

Biodegradable nanocomposites were obtained from polylactic acid (PLA) and cellulose nanofibers with diameters ranging from 11 nm to 44 nm. The influence of treated (with 3-aminopropyltriethoxysilane) and untreated nanofibers on the thermal properties of PLA was investigated in detail using multiple session Differential Scanning Calorimetry (DSC) analysis. The nucleating effect of the cellulose nanofibers was confirmed by all the DSC runs (two melting and two crystallization steps). The morphology of both neat PLA and nanocomposites was explored for the first time using a new powerful AFM technique, Peak Force QNM (Quantitative Mechanical Property Mapping at the Nanoscale), which emphasized the nanolevel characteristics by elastic modulus mapping. QNM analyses showed a better dispersion of the silane treated nanofibers in the matrix as compared to the untreated ones. Moreover, a higher degree of crystallinity was detected in the PLA composites containing untreated nanofibers compared to the composites with treated ones. © 2012 Elsevier Ltd.


Badescu V.,Romanian National Institute for Research and Development in Chemistry and Petrochemistry
Revue Roumaine de Chimie | Year: 2014

The aim of this article is the study of the fragmentation reactions of tetraethoxysiloxane (TEOS) as a precursor in the sol-gel process initiated by electronic impact in the ionization chamber of a mass spectrometer. Mass spectrum of an organic substance, as well as a silicon alkoxide such as TEOS is the result of a series of unimoleculare consecutive and competitive chemical reactions, which constitutes a pattern of fragmentation. The molecular ion of TEOS at mass 208 is a radical cation with positive delocalizated charge on the alkoxi bond Si-O-C. The primary fragmentation ions at masses 207, 193, 179 and 163 were obtained experimentally by B/E linked scan. The radical induced fragmentation reactions of the primary ions obtaining are presented and their existence is supplementary argued by measuring the ion masses at high resolution, the quantum calculations of the net atomic charges and the calculation of the double bond equivalent.


Nicolescu T.-V.,Romanian National Institute for Research and Development in Chemistry and Petrochemistry | Sarbu A.,Romanian National Institute for Research and Development in Chemistry and Petrochemistry | Ovidiu Dima S.,Romanian National Institute for Research and Development in Chemistry and Petrochemistry | Nicolae C.,Romanian National Institute for Research and Development in Chemistry and Petrochemistry | Donescu D.,Romanian National Institute for Research and Development in Chemistry and Petrochemistry
Journal of Applied Polymer Science | Year: 2013

We report the synthesis of molecularly imprinted sorbents, selective for gallic acid. The particles were prepared by using acrylic acid, acrylonitrile, and hydroxyethyl methacrylate as functional monomers, whereas ethyleneglycol dimethacrylate and 1,4-buthanediol dimethacrylate were used as crosslinkers. Preparation and manipulation protocols were adjusted considering template's nature. To highlight the influence of monomer/crosslinker nature upon imprinted particles, the adsorption capacity, the imprinting factor, and the distribution and selectivity coefficients were calculated. An imprinting factor of 3.53 and a selectivity coefficient of 6.86 were found for hydroxyethyl methacrylate/ethylene glycol methacrylate system. Copyright © 2012 Wiley Periodicals, Inc.


Panaitescu D.M.,Romanian National Institute for Research and Development in Chemistry and Petrochemistry | Frone A.N.,Romanian National Institute for Research and Development in Chemistry and Petrochemistry | Nicolae C.,Romanian National Institute for Research and Development in Chemistry and Petrochemistry
European Polymer Journal | Year: 2013

Nanocomposites from polyamide 11 and dried cellulose nanofibers (CNs), 16-30 nm in thickness and 50-400 nm in length, were prepared via direct melt mixing and their micro- and nano-mechanical properties were studied. (PF) QNM (Quantitative Nanomechanical Mapping) method was used to map nanomechanical properties at the surface of polyamide 11 and nanocomposites. This new AFM method emphasized both the increased modulus in nanocomposites as compared to the matrix and the microstructure on different levels in polyamide 11 and its nanocomposites. PF QNM showed that their crystalline structure consists of bundles of lamellar stacks, 200-350 nm in width and 20-40 nm wide lamellar stacks. Moreover, PF QNM study emphasized higher structural order in nanocomposites with 3 and 5 wt.% CNs and lower in the nanocomposite with 8 wt.% CNs as compared to the reference. These observations were verified and are consistent with both crystallinity values determined by DSC and micro-mechanical test results. The oriented bundles of lamellar stacks, observed by PF QNM, could be considered as the main blocks determining high mechanical properties for the studied nanomaterials. © 2013 Elsevier Ltd. All rights reserved.


Oprescu E.-E.,Petroleum Gas University of Ploiesti | Stepan E.,Romanian National Institute for Research and Development in Chemistry and Petrochemistry | Dragomir R.E.,Petroleum Gas University of Ploiesti | Radu A.,Romanian National Institute for Research and Development in Chemistry and Petrochemistry | Rosca P.,Petroleum Gas University of Ploiesti
Fuel Processing Technology | Year: 2013

In the general context of replacing classical fuel with alternative fuels based on renewable raw materials, biodiesel production has increased in the last years, generating a large amount of glycerol as by-product. Therefore, it is important to find new applications for the excess of produced glycerol. This paper presents the synthesis of three oxygenated compounds, obtained from catalytic condensation of glycerol with ketones. Glycerol derivatives were prepared in very good yields using solid superacid SO4 2 -/SnO2 as catalyst. The influence of blended ratio of oxygenated compound synthesized on the quality parameters of diesel fuel like viscosity, pour point and flash point was studied. © 2013 Elsevier B.V. All rights reserved.


Panaitescu D.M.,Romanian National Institute for Research and Development in Chemistry and Petrochemistry | Vuluga Z.,Romanian National Institute for Research and Development in Chemistry and Petrochemistry | Radovici C.,Romanian National Institute for Research and Development in Chemistry and Petrochemistry | Nicolae C.,Romanian National Institute for Research and Development in Chemistry and Petrochemistry
Polymer Testing | Year: 2012

The effect of styrene-(ethylene-co-butylene)-styrene triblock copolymer (SEBS) on the mechanical, thermal and morphological properties of polypropylene (PP) composites filled with nanosilica particles is investigated. A simultaneous increase of all tensile characteristics is observed in PP/nanosilica composites without SEBS and containing 5%SEBS and a large plastic deformation in the nanocomposite with 10%SEBS. Different amounts of β-PP are detected by X-ray diffraction analysis and the calculated K-values correlate well with differential scanning calorimetry results. Quantitative mechanical characterization of nanocomposites is performed at nanolevel, using peak force QNM. This AFM technique allows the detection of nanosilica particles and SEBS domains at the surface of samples and gives indications of local interactions between nanosilica and the matrix from the correlation of modulus and adhesion maps, and the increased local values of elastic modulus on extended areas around nanoparticles. © 2012 Elsevier Ltd. All rights reserved.


Ion R.M.,Romanian National Institute for Research and Development in Chemistry and Petrochemistry
Journal of Biological Physics | Year: 2011

Photodynamic inactivation is a new promising approach to treat bacterial infections. Usually, the evaluation of the efficacy of this method is done through time-consuming and labor-intensive microbiological test methods. This paper describes the development and implementation of an optical method to evaluate the photodynamic inactivation of bacteria based on non-invasive diffuse reflectance measurements. Five Staphylococcus aureus cultures and 15 mice have been used in this study. A skin lesion was created on the back of all animals, and it was contaminated with S. aureus (5.16 ± 0.013 log CFU/ml). Toluidine Blue O (c = 8.67 × 10 - 3 M) has been used as a photosensitiser agent. The bacterial cultures and animals were exposed to laser radiation (λ = 635 nm, P = 15 mW, DE = 8.654 J/cm2) for 20 min. The photodynamic inactivation of bacteria was monitored by acquiring the wounds' reflection spectra at different time points and by microbiological exams on the bioptical material. The good correlation between the diffuse reflectance and colony-forming units demonstrates the value of this optical method based on diffuse reflectance measurements as a rapid technique to monitor photodynamic bacterial inactivation. © 2010 Springer Science+Business Media B.V.


Peteu S.F.,Michigan State University | Peteu S.F.,Romanian National Institute for Research and Development in Chemistry and Petrochemistry | Boukherroub R.,Institut Universitaire de France | Szunerits S.,Institut Universitaire de France
Biosensors and Bioelectronics | Year: 2014

The importance of the so-called reactive nitrogen and oxygen species (RNOS) in biology and food technology has been widely recognized. However when these species are in excess, the steady-state maintained by physiological processes is disturbed. At this point, the nitro oxidative metabolic stress develops and its action in vivo over time leads to nitro-oxidative reactions in food and in living organisms, but also results in chronic degenerative diseases. Analytical methods enabling the assessment of the total antioxidant activity of a biological sample or a plant extract is therefore largely sought after. The ability of biosensors for rapid and real-time analysis that decreases the assay time and the possibility of automated and multi-analyte analysis at low cost has also allowed the quantitative and qualitative detection of RNOS. Among these RNOS, peroxynitrite (ONOO-) is a well-known inflammatory mediator during a number of physiological and pathological processes. Consequently, many efforts are underway to detect peroxynitrite in the biomedical field. This urgent demand makes the development of ONOO- specific probes of great interest. Not only they can be useful for the detection of disease states, but they will also allow for a screening-type analysis of potential signal transduction pathways in the cells.This invited review will critically discuss for the first time the very latest advancements and the challenges in the field of peroxynitrite biosensors and probes for in vivo and in vitro studies. Also, the main trends will be extracted, in order to chart the future directions and hence create an instrumental outlook. © 2014 Elsevier B.V.

Loading Romanian National Institute for Research and Development in Chemistry and Petrochemistry collaborators
Loading Romanian National Institute for Research and Development in Chemistry and Petrochemistry collaborators