Roman Jedrzejewski

Dr. Roman Jedrzejewski

orcid

Research Focus & Metrics

Academic Career Length

21Years (2006-Present)

(Calculated once Scilit publication data is synced: current year − year of first publication + 1)

Representative Publications

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9 October 2019 in Polymers
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Journal Article
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JPJoanna Piwowarczyk
Joanna Piwowarczyk
RJRoman Jedrzejewski
Roman Jedrzejewski
DMDariusz Moszyński
Dariusz Moszyński
KKKonrad Kwiatkowski
Konrad Kwiatkowski
Agata NiemczykAgata Niemczyk
Agata Niemczyk
JBJolanta Baranowska
Jolanta Baranowska
Two methods—attenuated total reflection Fourier infrared spectroscopy (ATR-FTIR) and X-ray photoelectron spectroscopy (XPS)—have been used to analyze the chemical structure of polytetrafluorethylene (PTFE) thin coatings deposited by pulsed laser (PLD) and pulsed electron beam (PED) ablations. The volume of the analyzed materials is significantly different in these techniques which can be of great importance in the characterization of highly heterogeneous thin films. Optical microscopy, atomic force microscopy (AFM) and scanning electron microscopy (SEM) have been additionally used to examine the coating surface morphology. The studies have shown that in the case of thin polymer coatings deposited by physical methods, the application for chemical structure evaluation of complementary techniques, with different surface sensitivity, together with the use of surface topography imaging, provide unique insight into the film morphology. The results can provide information contributing to an in-depth understanding of the deposition mechanism of polymer coatings.

1 August 2010 in Applied Catalysis A: General
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NNNARKIEWICZ NARKIEWICZ
NARKIEWICZ NARKIEWICZ
MPM. Podsiadły
M. Podsiadły
RJRoman Jedrzejewski
Roman Jedrzejewski
IPI. Pełech
I. Pełech

1 May 2019 in International Journal of Biological Macromolecules
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Journal Article
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Magdalena ZdanowiczMagdalena Zdanowicz
Magdalena Zdanowicz
RJRoman Jedrzejewski
Roman Jedrzejewski
RPRyszard Pilawka
Ryszard Pilawka

14 February 2019 in Journal of Materials Engineering and Performance
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AGAdam Gilewicz
Adam Gilewicz
RJRoman Jedrzejewski
Roman Jedrzejewski
PMPiotr Myslinski
Piotr Myslinski
BWBogdan Warcholinski
Bogdan Warcholinski
AlCrN coatings were deposited on steel substrates (HS6-5-2) using cathodic arc evaporation. The effect of nitrogen pressure on the properties of CrAlN coatings formed from Al80Cr20 cathode, such as chemical and phase composition of the coatings, surface morphology, deposition rate, hardness and adhesion to the substrate, and friction and wear were investigated. The coating deposited at nitrogen pressure of 3 Pa shows the highest deposition rate. The roughness parameter Ra of the coating surface decreases with increasing nitrogen pressure during its formation. The test results showed that the AlCrN coatings deposited under nitrogen pressure in the range from 1 to 5 Pa show similar hardness for all the coatings, which is around 17 GPa. The increase in the negative bias voltage of the substrate during the formation of the coating deteriorates its adhesion to the substrate, although the wear rate is rather good, about 1.4 × 10−7 mm3/Nm. The coatings deposited at nitrogen pressure of 3-4 Pa are characterized by the highest critical load, 95 N. Despite worse adhesion, these coatings are characterized by high resistance to wear, the wear rate is about 1.4 × 10−7 mm3/Nm.

1 November 2018 in Industrial Crops and Products
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Journal Article
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JAJakub Adamus
Jakub Adamus
TSTadeusz Spychaj
Tadeusz Spychaj
Magdalena ZdanowiczMagdalena Zdanowicz
Magdalena Zdanowicz
RJRoman Jedrzejewski
Roman Jedrzejewski

23 August 2019 in Polymers
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Magdalena ZdanowiczMagdalena Zdanowicz
Magdalena Zdanowicz
PSPiotr Staciwa
Piotr Staciwa
RJRoman Jedrzejewski
Roman Jedrzejewski
TSTadeusz Spychaj
Tadeusz Spychaj
The aim of this work was to prepare sugar alcohol-based deep eutectic solvents (DES) and test them as starch plasticizers. Thermoplastic starch (TPS) films were obtained via a simple and convenient thermocompression method. Influence of starch/DES premixtures conditioning (preheating, storage time) on TPS properties was investigated. TPS/sorbitol (S)-based DES exhibited similar tensile strength (TS) (8.6 MPa) but twice higher elongation at the break (ε) (33%) when compared with TPS plasticized only with S. Extra treatment, i.e., heating or prolonged storage time, facilitated starch/DES plasticizing. Starch with selected DES was also extruded and the influence of preconditioning and extrusion rotational speed were subsequently studied on thermocompressed films. Extrusion at 100 rpm led to films with TS up to ca. 10 MPa and ε up to 52%. Some differences in film samples morphology obtained via two processing methods were observed. X-ray diffractograms revealed that extruded samples exhibited a V-type peak at 18.2°, with intensity depending on plasticizer total molecular size. Applied techniques (mechanical tests, XRD, Dynamic Mechanical Analysis (DMA), FTIR-Attenuated Total Reflection (ATR), and moisture sorption) indicated that S-based DES forms stronger interactions with starch than glycerol (G) only used as conventional plasticizer, thus leading to better mechanical properties and inhibited tendency to starch recrystallization (studied up to one year).