2021 - Repozytorium publikacji - Politechnika Gdańska

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Surface and interfacial anti-plane waves in micropolar solids with surface energy
- Mriganka Shekhtar Chaki
- Victor Eremeev
- Abhishek K Singh
2021 MATHEMATICS AND MECHANICS OF SOLIDS
In this work, the propagation behaviour of a surface wave in a micropolar elastic half-space with surface strain and kinetic energies localized at the surface and the propagation behaviour of an interfacial anti-plane wave between two micropolar elastic half-spaces with interfacial strain and kinetic energies localized at the interface have been studied. The Gurtin–Murdoch model has been adopted for surface and interfacial elasticity. Dispersion equations for both models have been obtained in algebraic form for two types of anti-plane wave, i.e. a Love-type wave and a new type of surface wave (due to micropolarity). The angular frequency and phase velocity of anti-plane waves have been analysed through a numerical study within cut-off frequencies. The obtained results may find suitable applications in thin film technology, non-destructive analysis or biomechanics, where the models discussed here may serve as theoretical frameworks for similar types of phenomena.
Surface modification of PMMA polymer and its composites with PC61BM fullerene derivative using an atmospheric pressure microwave argon plasma sheet
- Andrzej Sikora
- Dariusz Czylkowski
- Bartosz Hrycak
- Magdalena Moczała-Dusanowska
- Marcin Łapiński
- Mirosław Dors
- Mariusz Jasiński
2021 Pełny tekst Scientific Reports
This paper presents the results of experimental investigations of the plasma surface modification of a poly(methyl methacrylate) (PMMA) polymer and PMMA composites with a [6,6]-phenyl-C61-butyric acid methyl ester fullerene derivative (PC61BM). An atmospheric pressure microwave (2.45 GHz) argon plasma sheet was used. The experimental parameters were: an argon (Ar) flow rate (up to 20 NL/min), microwave power (up to 530 W), number of plasma scans (up to 3) and, the kind of treated material. In order to assess the plasma effect, the possible changes in the wettability, roughness, chemical composition, and mechanical properties of the plasma-treated samples’ surfaces were evaluated by water contact angle goniometry (WCA), atomic force microscopy (AFM), attenuated total reflectance Fourier transform infrared spectroscopy (ATR-FTIR) and X-ray photoelectron spectroscopy (XPS). The best result concerning the water contact angle reduction was from 83° to 29.7° for the PMMA material. The ageing studies of the PMMA plasma-modified surface showed long term (100 h) improved wettability. As a result of plasma treating, changes in the samples surface roughness parameters were observed, however their dependence on the number of plasma scans is irregular. The ATR-FTIR spectra of the PMMA plasma-treated surfaces showed only slight changes in comparison with the spectra of an untreated sample. The more significant differences were demonstrated by XPS measurements indicating the surface chemical composition changes after plasma treatment and revealing the oxygen to carbon ratio increase from 0.1 to 0.4.
Surface quality control of a thin SiN layer by optical measurements
- Jakub Gierowski
- Sandra Pawłowska
2021 Pełny tekst Photonics Letters of Poland
Fiber optic interferometers have a wide range of applications, including biological and chemical measurements. Nevertheless, in the case of a reflective interferometer setup, standard silver mirrors cannot be used in every measurement, due to their chemical activity. This work investigates the surface quality of a thin optical layer of silicon nitride (SiN), which can serve as an alternative material for silver mirrors. We present measurements carried out with a Fabry-Perot fiber-optic interferometer working in a reflective mode. Measurement results allow us to determine the surface quality of the investigated layer.
Surface Roughness Evaluation in Thin EN AW-6086-T6 Alloy Plates after Face Milling Process with Different Strategies
- Daniel Chuchała
- Michał Dobrzyński
- Danil Yurievich Pimenov
- Kazimierz Orłowski
- Grzegorz Królczyk
- Khaled Giasin
2021 Pełny tekst Materials
Lightweight alloys made from aluminium are used to manufacture cars, trains and planes. The main parts most often manufactured from thin sheets requiring the use of milling in the manufacturing process are front panels for control systems, housing parts for electrical and electronic components. As a result of the final phase of the manufacturing process, cold rolling, residual stresses remain in the surface layers, which can influence the cutting processes carried out on these materials. The main aim of this study was to verify whether the strategy of removing the outer material layers of aluminium alloy sheets affects the surface roughness after the face milling process. EN AW-6082-T6 aluminium alloy thin plates with three different thicknesses and with two directions relative to the cold rolling process direction (longitudinal and transverse) were analysed. Three different strategies for removing the outer layers of the material by face milling were considered. Noticeable differences in surface roughness 2D and 3D parameters were found among all machining strategies and for both rolling directions, but these differences were not statistically significant. The lowest values of Ra = 0.34 µm were measured for the S#3 strategy, which asymmetrically removed material from both sides of the plate (main and back), for an 8-mm-thick plate in the transverse rolling direction. The highest values of Ra = 0.48 µm were measured for a 6-mm-thick plate milled with the S#2 strategy, which symmetrically removed material from both sides of the plate, in the longitudinal rolling direction. However, the position of the face cutter axis during the machining process was observed to have a significant effect on the surface roughness. A higher surface roughness was measured in the areas of the tool point transition from the up-milling direction to the down-milling direction (tool axis path) for all analysed strategies (Ra = 0.63–0.68 µm). The best values were obtained for the up-milling direction, but in the area of the smooth execution of the process (Ra = 0.26–0.29 µm), not in the area of the blade entry into the material. A similar relationship was obtained for analysed medians of the arithmetic mean height (Sa) and the root-mean-square height (Sq). However, in the case of the S#3 strategy, the spreads of results were the lowest.
Surface Texture after Turning for Various Workpiece Rigidities
- Michał Dobrzyński
- Karolina Miętka
2021 Pełny tekst Machines
In the paper, we present an analysis of the surface texture of turned parts with L/D (length/diameter) ratios of 6 and 12 and various rigidity values. The studies were carried out on samples made of S355JR steel and AISI 304 stainless steel. A detailed analysis of 2D surface profiles was carried out by using a large number of parameters that allowed us to distinguish significant differences in the surface microgeometry, which confirmed that determining surface characteristics from one height parameter (Ra—arithmetical mean height) is far from sufficient. The obtained results indicate significantly better roughness and waviness values of the AISI 304 steel surfaces in terms of its size, periodicity, and regularity. Therefore, the turning process of AISI 304 shafts with low rigidity allows one to be able to achieve better quality texture and have a positive effect on the general properties of a workpiece. In all tested samples, surface irregularities decreased along with the distance from the tailstock. The shafts with an L/D ratio of 12 had worse surfaces in the first two sections due to lower rigidity. The results received close to the three-jaw chuck, regardless of the L/D ratio and material type, demonstrated similar waviness and roughness parameters and profiles.
Surpassing the Line: Urban-Oriented Strategies in the Development of Business Complexes in Poland
- Piotr Lorens
- Joanna Bach-Głowińska
- Michał Habier
- Paweł Rzepecki
2021 Pełny tekst Urban Planning
Development trends regarding the business-related urban complexes seem to evolve from the “big-box” towards the more “multi-use” types of structures. Within it, the special role is reserved for places, which—due to economic, political, and geographical reasons—have not been previously considered as major business hubs. Only recently, places like cities in Central and Eastern Europe have become attractive locations for business complexes. These could offer centrally located and attractive locations for new structures, which resulted in the development of the new type of commercial centers—in the form of multi-use districts, walkable, and complemented by other uses. Therefore, to some extent, these cities “surpassed the development line” of the commercial and business complexes, and have become home to something much more advanced. Within the article, the cases from Poland, including Gdańsk, Warsaw, Cracow, and Wroclaw, are discussed. Not only is the urban arrangement of selected complexes presented, but the planning and socio-economic, legal, and infrastructural aspects of these developments are also discussed.
Surrogate-Assisted Design of Checkerboard Metasurface for Broadband Radar Cross-Section Reduction
- Muhammad Abdullah
- Sławomir Kozieł
2021 Pełny tekst IEEE Access
Metasurfaces have been extensively exploited in stealth applications to reduce radar cross section (RCS). They rely on the manipulation of backward scattering of electromagnetic (EM) waves into various oblique angles. However, arbitrary control of the scattering properties poses a significant challenge as a design task. Yet it is a principal requirement for making RCS reduction possible. This article introduces a surrogate-based approach for rapid design optimization of checkerboard metasurfaces. Our methodology involves fast metamodels, and a combination of surrogate-assisted global optimization with local, gradient-based tuning. It permits an efficient control of the EM wave reflection characteristics, and ensures arriving at that the globally optimum solution within the assumed parameter space. The design procedure is fully automated. The framework is employed to develop a novel broadband checkerboard metasurface, where the RCS reduction is fundamentally based on the backward scattering manipulation carefully controlled by simultaneous adjustment of the unit cell dimensions. The properties of the structure are demonstrated using simulated monostatic and bistatic RCSs. The proposed metasurface exhibits 6 dB RCS reduction within the frequency range from 16 to 37 GHz. The numerical results are validated using physical measurements of the fabricated prototype. Experimental data indicates that the relative RCS reduction bandwidth is 83 percent, which makes the proposed structure outperforming the designs reported in the literature.
Survey on opportunities and barriers in lighting controls
- Bruno Bueno Unzeta
- Jan de Boer
- Ruben Delvaeye
- Bertrand Deroisy
- Marc Fontoynont
- David Geisler-Moroder,
- Niko Gentile,
- Tao Luo
- Daniel Neves Pimenta
- Per Reinhold
- Michelangelo Scorpio
- Sergio Sibilio
- Natalia Sokół
- Sophie Stoffer
- Robert Weitlaner
2021
This report summarizes a survey performed in eight countries on the status quo of daylight and electric lighting control systems. Feedback from more than 100 international experts (building / facility managers and planers) was evaluated. The aim of the survey was to identify the perception of the different possibilities of the current lighting control solutions and the expectations about the control systems. The survey aims to provide a mapping of the current lighting control systems available at the market and an overview of which functions are perceived as most important and which areas are found to be improved. Participants of the survey had to rank each question in relation to the perceived importance and the need for improvement. The survey enclosed five general topics; energy, operational aspects, occupant control, occupant comfort and control functionality. The findings from the summary suggest, that the two main reasons for the implementation of lighting control systems are: 1. The possibility to reduce the electric lighting consumptions and 2. The opportunity to increase the user’s well-being and thereby reduce complaints from the users. From a user perspective, this means that the lighting system must ensure visual acuity and comfort by providing a sufficient level of illuminance and the ability to regulate the light level. Always in relation to the task and the ambient light in the space, and thereby creating a pleasant and comfortable light environment. Research suggests, when giving the users some manual control possibilities, the satisfaction with the lighting conditions in general increases The users should be able to both increase and dim the light levels or completely turn it off. This suggests, if the lighting control system is designed to regulate the illuminance automatically, it should be provided some kind of manual override. This is supported by the findings in the surveys, where all countries in one way or another find it important to provide the users with some possibility of user control. This as well applies to the control of the shading system in relation to avoid glare from high daylight intensities and undesired solar radiation coming into the space.
Sustainable development model for measuring and managing sustainability in the automotive sector
- Dominik Jasiński
- James Meredith
- Kerry Kirwan
2021 Pełny tekst SUSTAINABLE DEVELOPMENT
A growing number of organizations across a variety of industries are now pursuing sustainable management business goals to improve business efficiency, manage stakeholder expectations, or for legislative compliance. This is also the case for automotive manufacturing organizations who are under pressure from their stakeholders to manage and improve sustainability performance. This requires the development of credible measurement tools and systems to enable capture and monitoring of sustainability. This paper describes the development process for an innovative model, named the Automotive Sustainability Assessment Model (A-SAM), to drive sustainable decision-making in the automotive sector. The process of developing the model consisted of four major steps, each of which contained series of intermediate steps, individual objectives, and research methods. The model measures, quantifies, and translates a broad range of external effects (both positive and negative) into their monetary equivalents, enabling large car manufacturers to evaluate options, identify win–wins, and optimize trade-off, while making complex and multidisciplinary sustainability decisions. It allows managers and design engineers in the automotive sector to develop a better understanding of the environmental, resource, and social impacts of their activities, products, processes, and materials used, while still ensuring cost-effectiveness when making decisions. The A-SAM shows promise as an effective tool for supporting sustainability decisions in a business environment. Although developed in the context of the automotive industry, it can be adapted by organizations of any type, operating across many different sectors for managing sustainability in a more holistic, comprehensive, and integrated manner.
Sustainable Fashion in Poland—Too Early or Too Late?
- Magdalena Popowska
- Aleksandra Sinkiewicz
2021 Pełny tekst Sustainability
This article presents an analysis of the concept of sustainable fashion from the Polish consumer’s perspective. The aim of this research is to investigate how Polish fashion consumers approach the concepts of sustainability, such as organic, fair-trade, and carbon emissions. Exploring the experience of the Polish consumption context provides a richer understanding of the evolution of fashion sustainability concepts in this and similar countries. The research methods applied comprise the literature review, including the theoretical and empirical items, and the survey conducted among Polish clothing consumers. According to our findings, they declare caring more about the general environment but do not pay attention to sustainable development in the clothing industry. It is also worth noting that Poles, compared to other consumers in selected markets, have an unfavourable opinion of their own nation on the approach to sustainable development in the garment industry.
Sustainable recovery of plant essential Nitrogen and Phosphorus from human urine using industrial coal fly ash
- Mahesh Ganesapillai
- Jakub Drewnowski
- Shivendu Ranjan
- Thirumalini Selvaraj
2021 Environmental Technology & Innovation
Coal-based thermal power plants play a pivotal role in meeting global energy demand. The amount of fly ash generated from these plants increases every year, and its successful use has posed a significant environmental risk in the last decade. In this study, coal fly ash was packed in a fixed-bed adsorption column to remove Urea–N from synthetic human urine. To assess the efficacy of fly ash in the removal of Nitrogen, various process parameters were tested, including initial urea concentration in urine (20, 40, 60%), fly ash loading in column (100, 150, 200 g), and urine flow rate through the column (2, 4, 6 L.h−1). The initial urea concentration and bed height were found to have a major impact on nutrient recovery. Following nitrogen removal, the effluent urine was de-phosphatized using struvite precipitation and approximately 83% of phosphorus was recovered. High inlet urine concentration (60%), high flow rate (6 L.h−1) and minimal adsorbent loading (100 g) resulted in maximum struvite precipitation. The column breakthrough and characteristic parameters of four different models were predicted using kinetic modelling of the adsorption data, in which Yoon-Nelson and Thomas’ models suggested efficient removal and recovery of plant essential nutrients. As a result of the findings, coal fly ash appears to be a promising adsorbent for extracting these important plant nutrients. The effect of initial urine concentration, fly ash loading in the column, and urine flow rate on dephospatisation was calculated. The findings of this study will shed light on the process of nutrient adsorption process selection and detail the comparative differences between continuous and batch nutrient recovery of human urine.
Sustainable upcycling of brewers’ spent grain by thermo-mechanical treatment in twin-screw extruder
- Aleksander Hejna
- Mateusz Barczewski
- Katarzyna Skórczewska
- Joanna Szulc
- Błażej Chmielnicki
- Jerzy Korol
- Krzysztof Formela
2021 Pełny tekst JOURNAL OF CLEANER PRODUCTION
Thermo-mechanical treatment of brewers’ spent grain (a by-product of beer manufacturing) was successfully performed via the extrusion process. The impact of temperature (from 30 to 180 °C), throughput (from 1 to 5 kg/h) and screw speed (from 75 to 375 rpm) on particle size, color, chemical structure, antioxidant activity and thermal stability of resulting material, as well as correlations between particular properties, were investigated. The color of treated brewers’ spent grain was strongly influenced by particle size and the extent of Maillard reactions occurring during extrusion, responsible for the browning of material. Moreover, products of these reactions, melanoidins, enhanced the antioxidant activity of brewers’ spent grain, which after extrusion at 180 °C was increased by even 100%. Thermo-mechanical treatment of brewers’ spent grain at 120 and 180 °C increased its thermal stability investigated by thermogravimetric analysis. It was also observed that temperature treatment above 100 °C also led to the reduction in friction inside the extruder barrel and reduced by at least 20% specific mechanical energy required to brewers’ spent grain modification, which positively affects the economic aspect of the process. The results confirm that a proper adjustment of extrusion parameters allows easy tailoring of the appearance (color, particle size distribution) and performance properties (thermal stability, antioxidant activity) of brewers’ spent grain, which significantly extend applications of this cellulosic-rich waste in wood polymer composites technology.
Sustainable Use of the Catenary by Trolleybuses with Auxiliary Power Sources on the Example of Gdynia
- Mikołaj Bartłomiejczyk
- Marcin Połom
2021 Pełny tekst Infrastructures
The current developments in onboard power source technology, in particular, traction batteries, open up new potential in trolleybus transport and also make it possible to introduce electric buses. Thus far, trolleybus transport has required the presence of overhead lines (OHL). Introducing trolleybuses with onboard batteries makes it possible to grow the zero-emissions transport network in places with limited power supply capabilities and low population density, or in places where building OHL would not be possible. This improves the efficiency of trolleybus transport and makes environmentally friendly public transport more accessible to the local citizens. Despite their obvious advantages, traction batteries can also be problematic, as the drivers may overuse them (e.g., in the event of pantograph failure), and the public transport authorities and transport companies may plan connections in an ineffective way without preparing the necessary infrastructure (the absence of slipways or automatic connection capabilities), which in turn leads to inefficient use of the OHL. The article outlines the operation of the trolleybus transport network in Gdynia. The use of traction batteries in regular connections is analysed, and the potential for electrification of the bus line, some sections of which follow the traction infrastructure, is examined.
Synagogi dawnej Polski - ich teraźniejszość i przyszłość
- Joanna Kabrońska
2021
Tekst stanowi próbę ujęcia w szerszej perspektywie złożonego zjawiska zmiany formy użytkowania ocalałych obiektów kultu religijnego. Postępująca sekularyzacja współczesnych społeczeństw stanowi wyzwanie dla religijnych społeczności różnych wyznań, przynosząc również pytania dotyczące zmiany przeznaczenia pustoszejących świątyń. Biorąc pod uwagę społeczny kontekst zarysowany powyżej, ocalałe budynki synagog można uznać za odrębny, trudny problem. Dawne społeczności żydowskie, będące gospodarzami obiektów, stały się ofiarami wojny, a nieliczni, którzy przetrwali wojnę, wyjechali z Polski w kolejnych falach emigracji. Pozostały bóżnice i cmentarze, którymi nie ma się kto opiekować, ponieważ nie istnieje już wspólnota religijna. Wskazanie formy użytkowania budynków, które pierwotnie były domami modlitwy i miejscami zebrań gminy żydowskiej, nie byłoby właściwe bez dopuszczenia do głosu współczesnej społeczności żydowskiej. Jednak różnorodność poglądów i interpretacji, związana z tym problemem, czyni zadanie jeszcze trudniejszym. Rozpatrując zjawisko zmiany formy użytkowania ocalałych synagog, warto również zwrócić uwagę na rolę artystów, którzy uczynili architekturę ocalałych obiektów kultu religijnego tworzywem swoich działań artystycznych. Często jako pierwsi ujawniają oni wrośnięte w krajobraz budynki i przywołują ich pierwotne przeznaczenie, czyniąc sztukę w pewnym sensie narzędziem resakralizacji tych obiektów i jednocześnie ukazując nowe kierunki myślenia o ich przyszłości.
Synergistic Effects of Propolis Combined with 2-Phenoxyethanol and Antipyretics on the Growth of Staphylococcus aureus
- Katarzyna Grecka
- Piotr Szweda
2021 Pełny tekst Pharmaceutics
The present investigation aimed to assess the combinational effect of commonly usedantipyretics and antiseptics with ethanolic extracts of propolis (EEPs) on the growth inhibition ofStaphylococcus aureus. The broth microdilution checkerboard assay revealed synergistic interactionsbetween all investigated antipyretics, namely acetylsalicylic acid, ibuprofen, and acetaminophen,with EEPs samples. The values of the fractional inhibitory concentration (ΣFIC) index for all thesecombinations were <0.5. While, in the case of considered antiseptics, namely chlorhexidine, octenidinedihydrochloride, and 2-phenoxyethanol, the positive interaction was confirmed only for the last one(values ofΣFIC in the range 0.0625–0.25). Combinations of two other agents with all four samples ofEEPs resulted in an important antagonistic effect (values ofΣFIC≥4.5). Propolis is mostly dedicatedto the treatment of skin/wound infections; thus, these findings are of particular practical importance.The outcomes of the study also support the hypothesis that the propolis’s antimicrobial effect is dueto the combined (synergistic) action of several ingredients rather than the presence of one componentof high antibacterial activity. The composition of 13 ingredients of EEPs (at a concentration belowthe MIC (minimum inhibitory concentration) of the most active agent) exhibited considerably highanti-staphylococcal efficiency with MIC = 128μg/mL.
Synteza, struktura chemiczna i właściwości bezizocyjanianowych poliuretanów otrzymywanych z wykorzystaniem CO2 oraz surowców pochodzenia naturalnego.
- Kamila Rohde
2021
Z uwagi na wciąż rosnącą świadomość proekologiczną, politykę zrównoważonego rozwoju, a także nurt zielonej chemii wiodącym trendem w przemyśle tworzyw sztucznych jest poszukiwanie alternatywnych metod otrzymywania materiałów polimerowych. Komercyjnie poliuretany otrzymywane są w wyniku reakcji poliaddycji di- lub poliizocyjanianów z poliolami i małocząsteczkowymi przedłużaczami łańcucha. Z uwagi na niekorzystne właściwości diizocyjanianów, a także prognozowane zmniejszenie zasobów ropy naftowej i związany z tym wzrost cen rynkowych surowców, ośrodki naukowo-badawcze poszukują nowych metod syntezy tych materiałów. Głównym celem prezentowanej rozprawy doktorskiej było otrzymanie bezizocyjanianowych poliuretanów w wyniku reakcji poliaddycji cyklicznych węglanów oraz di- lub poliamin z zastosowaniem monomerów pochodzenia roślinnego i dwutlenku węgla, jako reagenta wbudowywanego w strukturę eterów diglicydylowych. Cel realizowano poprzez wykorzystanie komercyjnie dostępnego poli(glikolu trimetylenowego) pochodzenia roślinnego oraz aminowych pochodnych zdimeryzowanych kawasów tłuszczowych. Ponadto, dwutlenek węgla w reakcji cykloaddycji wbudowywano w strukturę półproduktów zakończonych grupami oksiranowymi. Opracowana metoda nie wymaga zastosowania podwyższonego ciśnienia, możliwe jest kontrolowanie prędkości przepływu gazu, a także nie ma konieczności stosowania toksycznych rozpuszczalników organicznych. Niniejsza rozprawa doktorska oparta jest na czterech artykułach opublikowanych w recenzowanych czasopismach naukowych. W ramach prowadzonych prac badawczych szczegółowo scharakteryzowano strukturę chemiczną, a także wybrane właściwości otrzymywanych na każdym etapie prac produktów.
Synthesis and Characterization of Poly(zwitterionic) Structures for Energy Conversion and Storage
- Adrian Olejnik
- Siuzdak Katarzyna
- Katarzyna Grochowska
2021
Zwitterions are unique class of molecules that possess two functional groups bearing electric charges, one positive and second negative. This setup results in peculiar properties such as high water retention and anti-fouling capability. Therefore, zwitterionic coatings and gels are commonly applied in e.g. biosensing and bioelectronic devices. Despite those applications, there are other perspectives for zwitterionic materials. Recently, they have gained attention in the fields of energy storage and conversion. In particular, gel electrolytes for batteries and solid state supercapacitors based on zwitterionic polymers have significantly higher ionic conductivity compared to standard electrolytes based on e.g. poly(vinyl alcohol). Moreover,the capacitance of devices with zwitterionic electrolytes is generally few times higher and retained after a larger number of cycles. Zwitterions are also prominent interlayers between photoactive materials and electrical contacts in organic and perovskite solar cells facilitating charge injection. Considering the unique properties of zwitterions and a large variety of available structures, they have become animportant point of scientific attention in the field of energy storage and conversion. Despite some concepts have already been developed, there is plenty to be discovered about these materials. In our opinion zwitterions can be regarded as the most prospective ones in energy fields.
Synthesis and Physicochemical Characteristics of Chitosan-Based Polyurethane Flexible Foams
- Agnieszka Piotrowska-Kirschling
- Adam Olszewski
- Jakub Karczewski
- Łukasz Piszczyk
- Joanna Brzeska
2021 Pełny tekst Processes
The use of shrimp waste to obtain chitosan (Ch) is an essential issue, considering a circular economy, waste management, and its application to environmentally friendly materials. In this study, northern prawn shells were utilized to obtain Ch, which could then be used for synthesizing chitosan-based polyurethane (PUR+Ch) foams with different Ch concentration. The chemical structure, morphology, hardness, thermal properties, viscoelastic properties, and sorption properties in relation to oil and water of these materials were determined. The results present that the addition of Ch into PUR influences the physicochemical characteristics and properties of the tested materials. PUR+Ch foams with 1–3 wt% Ch had more open cells and were softer than neat PUR. PUR+Ch1 had the best thermal properties. PUR+Ch2 foam with 2 wt% Ch as a whole was characterized as having the highest water sorption. The PUR+Ch1 foam with 1 wt% Ch had the best oil sorption. This paper shows that the modification of PUR by Ch is a very promising solution, and PUR+Ch foams can be applied in the water treatment of oil spills, which can be dangerous to the water environment.
Synthesis and structural characterization of bio-based bis(cyclic carbonate)s for the preparation of non-isocyanate polyurethanes
- Kamila Błażek
- Hynek Beneš
- Zuzana Walterová
- Sabina Abbrent
- Arantxa Eceiza
- Tamara Calvo-Correas
- Janusz Datta
2021 Polymer Chemistry
Bio-based cyclic carbonates are of significant research interest as monomers for non-isocyanate polyurethane (NIPU) synthesis. This research describes the synthesis of a series of five-membered bis(cyclic carbonate)s using bio-based polyether polyols (PO3G) with different molecular weights (250, 650 and 1000 g mol−1) and carbon dioxide as green feedstocks. The utilization of CO2 as a source of carbon in the chemical reaction is in agreement with the sustainable chemical industry. Furthermore, in order to support the green and sustainable polymer chemistry approach, the syntheses were attempted under solvent-free conditions. The implemented synthetic methods are focused on the design of processes and final products that minimize negative environmental impact. Detailed chemical structure analysis of synthesized products was performed using a combination of spectroscopy techniques (ATR-FTIR as well as 1D and 2D NMR techniques), mass spectrometry (MALDI-TOF MS) and chromatography analysis (SEC). The formation of the main product with two terminal cyclic carbonates was confirmed and the formed side products were also identified, characterized and quantified. Finally, as a proof of concept, the synthesized bis(cyclic carbonate)s were successfully used for the preparation of NIPU thermosets. Chemical and mechanical properties of the produced materials suggest their high potential for future applications, e.g. as sound absorbing materials.
Synthesis and Structure of Novel Copper(II) Complexes with N,O- or N,N-Donors as Radical Scavengers and a Functional Model of the Active Sites in Metalloenzymes
- Joanna Masternak
- Małgorzata Zienkiewicz-Machnik
- Iwona Łakomska
- Maciej Hodorowicz
- Katarzyna Kazimierczuk
- Milena Nosek
- Amelia Majkowska-Młynarczyk
- Joanna Wietrzyk
- Barbara Barszcz
2021 Pełny tekst INTERNATIONAL JOURNAL OF MOLECULAR SCIENCES
Toevaluatetheantioxidantactivityofpotentialsyntheticenzymemimetics,wepreparednewfivecopper(II)complexesviaaself‐assemblymethodandnamedthem[Cu(2‐(HOCH2)py)3](ClO4)2(1),[Cu(2‐(HOCH2)py)2(H2O)2]SiF6(2),[Cu2(2‐(HOCH2CH2)py)2(2‐(OCH2CH2)py)2](ClO4)2(3),[Cu(pyBIm)3](BF4)2∙1.5H2O(4)and[Cu(py2C(OH)2)2](ClO4)2(5).ThesyntheticprotocolinvolvedN,O‐ orN,N‐donors:2‐(hydroxymethyl)pyridine(2‐(HOCH2)py),2‐(hydroxyethyl)pyridine(2‐(HOCH2CH2)py),2‐(2‐pyridyl)benzimidazole(pyBIm),di(2‐pyridyl)ke‐tone(py2CO).TheobtainedCu(II)complexeswerefullycharacterisedbyelementalanalysis,FTIR,EPR,UV‐Vis,single‐crystalX‐raydiffractionandHirshfeldsurfaceanalysis.Crystallographicandspectroscopicanalysesconfirmedchromophoresofbothmonomeric({CuN3O3}(1),{CuN2O4}(2),{CuN6}(4),{CuN4O2}(5))anddimericcomplex({CuN2O3}(3)).Mostoftheobtainedspeciespos‐sessedadistortedoctahedralenvironment,exceptdimer3,whichconsistedoftwocoppercentreswithsquarepyramidalgeometries.Thewater‐solublecompounds(1,3and5)wereselectedforbiologicaltesting.Theresultsofthestudyrevealedthatcomplex1insolutionsdisplayedbetterradicalscavengingactivitythancomplexes3,5andfreeligands.Therefore,complex1hasbeenselectedforfurtherstudiestotestitsactivityasanenzymemimetic.Thechosencompoundwastestedontheerythrocytelysateoftwogroupsofpatientsafterundergoingchemotherapyandchemoradiotherapy.Theeffectofthetestedcompound(1)onenzymeactivitylevels(TAS,SODandCAT)suggeststhattheselectedcomplexcanbetreatedasafunctionalmimeticoftheenzymes.