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Search results for: POLY(LACTIC ACID)
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On the Correlation of Lignocellulosic Filler Composition with the Performance Properties of Poly(ε-Caprolactone) Based Biocomposites
PublicationIn this work, three types of agricultural waste: olive stones (OS), date seed (DS) and wheat bran (WB) were applied as potential lignocellulosic fillers in poly(ε-caprolactone) (PCL) based biocomposites. Differences in composites’ performance were related to the higher content of proteins, noted for WB comparing to other fillers applied, which enhanced plasticization of PCL matrix. The mechanical properties of biocomposites were...
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The synthesis and structure of a potential immunosuppressant: N-mycophenoyl malonic acid dimethyl ester
PublicationThe synthesis of a potential immunosuppressant, i.e. dimethyl ester of N-mycophenoyl malonic acid was optimized in the reaction of mycophenolic acid (MPA) with amino malonic dimethyl ester in the presence of propanephosphonic anhydride (T3P) as a coupling reagent. The structural properties of the obtained MPA derivative were investigated by NMR, MS and single crystal X-ray diffraction methods. Theoretical considerations of conformational...
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Thermal energy storage using stearic acid as PCM material
PublicationThis work presents an experimental study of thermal energy storage by use of PCM. The aim of the study was to establish the influence of different inlet temperature of heat transfer fluid (HTF) and different Reynolds number of HTF on intensity of charging process. The PCM used in this study was stearic acid and water was used as HTF. A copper helical coil mounted in cylindrical container served as a heat transfer surface.
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Determination of Chemical Diffusion Coefficient of Lithium Ions in Ceramics Derived from Pyrolysed Poly(1,2-dimethylsilazane) and Starch
PublicationThe apparent chemical diffusion coefficient Li+ (DappLI+) in pyrolysed poly(1,2-dimethylsilazane)/starch (PSN/S) (weight ratio: 30/70) ceramic anode composite is determined by galvanostatic intermittent titration technique (GITT). The electrode material composition is C6.00N0.14H0.47O0.12Si0.13. The calculated values of DappLI+, depend on the applied potential, vary from 10-14 to 10-9 [cm2/s]. The diffusion coefficient of lithium...
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Morphology and properties of recycled polyethylene/ground tyre rubber/thermoplastic poly(ester-urethane) blends
PublicationThe growing amount of plastics waste produced every year resulted in development of mechanical and chemical recycling methods of polymers and their blends or composites. From the environmental point of view, the possibility of plastics waste reusing and recycling is desirable. In this study three polymer blends were obtained with using recycled polyethylene (RPE), ground tyre rubber (GTR) and thermoplastic poly(ester-urethane)...
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Electrochemical synthesis and characterization of nanocomposites based on poly(3,4-ethylenedioxythiophene) and functionalized carbon nanotubes
PublicationThis work is focused on new composite materials consisting of poly(3,4-ethylenedioxythiophene) (pEDOT) and functionalized multi-walled carbon nanotubes synthesized electrochemically. Three types of composites were synthesized: the first one containing carbon nanotubes with carboxyl groups (covalent functionalization), the second one containing oxidized carbon nanotubes ox-MWCNTs (with different oxygen-rich polar groups) (covalent...
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Polyurethanes Crosslinked with Poly(vinyl alcohol) as a Slowly-Degradable and Hydrophilic Materials of Potential Use in Regenerative Medicine
PublicationNovel, slowly-degradable and hydrophilic materials with proper mechanical properties and surface characteristics are in great demand within the biomedical field. In this paper, the design, synthesis, and characterization of polyurethanes (PUR) crosslinked with poly(vinyl alcohol) (PVA) as a new proposition for regenerative medicine is described. PVA-crosslinked PURs were synthesized by a two-step polymerization performed in a solvent...
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Collagen and hyaluronic acid hydrogel in water-in-oil microemulsion delivery systems
PublicationThe efficacy of microemul-sion in dermal and transdermal delivery of active ingredients. Here, we assessed the water-in-oilmicroemulsion capacity to incorporate two natural polymers, i.e. collagen and hyaluronic acid withlow and high molecular weight. Systems were extensively characterized in terms of conductivity, phaseinversion studies, droplet diameter, polydispersity index and rheological properties. The results of thisresearch...
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Electrode materials for electrochemical capacitors based on poly(3,4-ethylenedioxythiophene) and functionalized multi-walled carbon nanotubes characterized in aqueous and aprotic electrolytes
PublicationWithin this work, we report a facile one-stage synthesis of nanocomposites based on functionalized carbon nanotubes (CNTs) and electroactive polymer poly(3,4-ethylenedioxythiophene). Three different composites are investigated as potential electrode materials for the electrochemical capacitors. Two of the composites contain carbon nanotubes (ox-CNTs), functionalized by acid oxidation process (65% HNO3, 120 °C). The third composite...
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Photoresponsive, amide-based derivative of embonic acid for anion recognition
PublicationThe synthesis and ion-binding properties of amide-based derivative of embonic acid andp-aminoazobenzenewere described. The new compound was characterized by X-ray structural analysis and spectroscopic methods.Ligand interacts in acetonitrile with Y-shaped anions (benzoates and acetates) and dihydrogen phosphatesforming complexes of 1:1 stoichiometry. In more polar DMSO the complexes stoichiometry changes to 2:1(L:anion). Light-inducedtranstocisisomerization...
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Electron-impact ionization cross section of formic acid
PublicationExperimental electron-impact ionization cross sections of one of the simplest carboxylic acids, formic acid, are presented. The molecular target was studied in two independent experimental setups applying different methods: the total ion collection and the electron–impact mass spectrometry methods. Experimental data were taken at incident electron energies ranging from ionization threshold [11.31 eV; J.C. Traeger, Int. J. Mass...
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Investigations on the immunosuppressive activity of derivatives of mycophenolic acid in immature dendritic cell
PublicationThe main activity of mycophenolic acid (MPA) and its analogs is the inhibition of proliferation of T cells. Here, we hypothesized that MPA and its conjugates inhibits also the activity of antigen-presenting cells (APC) including dendritic cells (DCs). We tested the effect of novel amino acid derivatives of MPA and conjugates of MPA with acridines/acridones on DCs by flow cytometry, ELISA and MLR assay. Both acridines/acridone derivatives...
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Characterization of fatty acid composition in Eurasian badger (Meles meles)
PublicationPolyunsaturated fatty acids (PUFAs, LA and ALA) are not synthesized in mammals in the absence of their essential fatty acid precursors. However, hibernating animals and animals sleeping through the winter need sufficiently high amounts of these acids. The Eurasian badger does not hibernate, but sleeps over winter. In the autumn the body weight of adult badgers increases even twofold, since they put on fat before the winter. Fat...
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Novel amides of mycophenolic acid and some heterocyclic derivatives as immunosuppressive agents
PublicationThe group of new amide derivatives of mycophenolic acid (MPA) and selected heterocyclic amines was synthesised as potential immunosuppressive agents functioning as inosine-5'-monophosphate dehydrogenase (IMPDH) uncompetitive inhibitors. The synthesis employed uronium-type activating system (TBTU/HOBt/DIPEA) while or phosphonic acid anhydride method (T3P/Py) facilitating amides to be obtained in moderate to excellent yields without...
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Chemical Structure and Thermal Properties versus Accelerated Aging of Bio-Based Poly(ether-urethanes) with Modified Hard Segments
PublicationAging of polymers is a natural process that occurs during their usage and storage. Predicting the lifetime of polymers is a crucial aspect that should be considered at the design stage. In this paper, a series of bio-based thermoplastic poly(ether-urethane) elastomers (bio-TPUs) with modified hard segments were synthesized and investigated to understand the structural and property changes triggered by accelerated aging. The bio-TPUs...
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Assessment of the impact of bacteria Pseudomonas denitrificans, Pseudomonas fluorescens, Bacillus subtilis and yeast Yarrowia lipolytica on commercial poly(ether urethanes)
PublicationThe assessment of the impact of the bacteria Pseudomonas denitrificans, Pseudomonas fluorescens, Bacillus subtilis and yeast Yarrowia lipolytica on commercial poly(ether urethanes) Tecoflex® and Tecothane® is presented. The polyurethane samples were incubated with pure cultures of the microorganisms at 30 °C for five months. The changes in the chemical structure of the polymers were evaluated using loss of weight and contact angle...
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Improvement of derivatized amino acid detection sensitivity in micellar electrokinetic capillary chromatography by means of acid-induced pH-mediated stacking technique
PublicationDerivatization is a frequently used sample prepara-tion procedure applicable to the enhancement of analyte de-tection sensitivity. Amino acids mostly require derivatization prior to electrophoretic or chromatographic analysis, especial-ly if spectrophotometric detection is used. This study presents an on-line preconcentration technique for derivatized amino acids. The sensitivity of the method was improved by the utilization of...
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Primary and secondary crystallization of poly(ethylene adipate)
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Poly(urethaneamideimide)s from a cycloaliphatic diisocyanate
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An overview of developments in poly(urethane-isocyanurates) elastomers
PublicationNauka i technologia jest przede wszystkim ukierunkowana na rozwój nowych materiałów polimerowych z pożądanych właściwościach. Takimi materiałami są bez wątpienia poliuretany zawierające w swojej strukturze pierścienie izocyjanurowe, charakteryzują się wysoką odpornością termiczną. Wiele z nich jest wykorzystywana jako sztywne pianki w budownictwie. Coraz większym zainteresowaniem cieszą się elastomery uretanowo-izocyjanurowe.
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Thermal degradation kinetics of poly(propylene succinate) prepared with the use of natural origin monomers
PublicationLinear biobased polyester polyols were prepared with the use of succinic acid and 1,3-pro- panediol (both with natural origin). Tetraisopropyl orthotitanate (TPT) was used as a catalyst. In order to determine the effect of various synthesis temperature conditions on the thermal degradation kinet- ics, nine sequences of temperature conditions were used during two-step polycondensation reaction. Thermogravimetric analysis was conducted...
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Fabrication of toughened plastic using styrene butadiene rubber-poly (methyl methacrylate) interpenetrating polymer networks
PublicationA standard set of interpenetrating polymeric networks (IPNs) has been contrived using an elastomerstyrene butadiene rubber and a thermoplastic poly (methyl methacrylate) through sequential polymerization protocol. This low-cost material can be hopefully engaged as a toughened plastic with cocontinuous morphology. Different morphological protocols including Raman imaging are effectively utilized to envisage the effect of blend ratio...
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Experimental investigation on heat pipes supported by soy wax and lauric acid for electronics cooling
PublicationThis paper presents an experimental study of heat pipes for electronics cooling that were supported by energy storage materials (i.e. phase change materials - PCMs) coated at the adiabatic section. The PCMs utilized included two materials, namely lauric acid and soy wax, the latter being considered as a more cost-effective alternative. The study focused on three different powers: 20 W, 25 W, and 30 W. Both heating, cooling, and...
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The mechanical properties and bactericidal degradation effectiveness of tannic acid-based thin films for wound care
PublicationThe surface area is the most important aspect when considering the interactions between a material and the surrounding environment. Chitosan (CTS) and tannic acid (TA) were previously successfully tested by us to obtain thin films to serve as wound dressings or food packaging materials. However, surface properties as well as the antimicrobial activity of the material were not considered. They are important if the material is likely...
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Degradable poly(ester-ether) urethanes of improved surface calcium deposition developed as novel biomaterials
PublicationBones, which are considered as hard tissues, work as scaffold for human body. They provide physical support for muscles and protect intestinal organs. Percentage of hard tissues in human body depends on age, weight, and gender. Human skeleton consists of 206 connected bones. Therefore, it is natural that the hard-tissue damage such as fractures, osteoporosis, and congenital lack of bone may appear. The innovative way of bone healing...
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Poly(ε-Caprolactone)/Brewers’ Spent Grain Composites—The Impact of Filler Treatment on the Mechanical Performance
PublicationWaste lignocellulose materials, such as brewers’ spent grain, can be considered very promising sources of fillers for the manufacturing of natural fiber composites. Nevertheless, due to the chemical structure differences between polymer matrices and brewers’ spent grain, filler treatment should be included. The presented work aimed to investigate the impact of fillers’ reactive extrusion on the chemical structure and the poly(ε-caprolactone)/brewers’...
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Dissociation of furan-2-carboxylic acid by low energy electrons
PublicationElectron attachment to molecular target can lead to a variety of negative fragment ions. We experi- mentally probe the main dissociative electron attachment channels in furan-2-carboxylic acid (C3H3O2 − COOH) - a molecular target composed of two important structural units: a furan ring and a carboxylic group. In our studies we utilise nearly mono-energetic electrons at electron energies from 0 eV up to 15 eV. Our detection setup...
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Dissociative electron attachment and anion-induced dimerization in pyruvic acid
PublicationWe report partial cross sections for the dissociative electron attachment to pyruvic acid. A rich fragmentation dynamics is observed. Electronic structure calculations facilitate the identification of complex rearrangement reactions that occur during the dissociation. Furthermore, a number of fragment anions produced at electron energies close to 0 eV are observed, that cannot originate from single electron-molecule collisions....
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Porosity and swelling properties of novel polyurethane–ascorbic acid scaffolds prepared by different procedures for potential use in bone tissue engineering
PublicationIn this work, a novel polyurethane (PU) system based on poly(ethylene-butylene) adipate diol, 1,6-hexamethylene diisocyanate, 1,4-butanediol, and ascorbic acid was used to prepare scaffolds with potential applications in bone tissue engineering. Two fabrication methods to obtain porous materials were chosen: phase separation (PS)/salt particle leaching (PL) and solvent casting (SC)/salt PL. The calculated porosity demonstrated...
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Compatibility of Sustainable Mater-Bi/poly(ε-caprolactone)/cellulose Biocomposites as a Function of Filler Modification
PublicationDespite their popularity and multiplicity of applications, wood–polymer composites (WPCs) still have to overcome particular issues related to their processing and properties. The main aspect is the compatibility with plant-based materials which affects the overall performance of the material. It can be enhanced by strengthening the interfacial adhesion resulting from physical and/or chemical interactions between the matrix and...
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Preparation of Pseudopeptides Building Blocks with Retro-Thioamide Bond Mediated via Thiocarbamoyl Meldrum's Acid
PublicationAn easy and efficient synthesis of pseudo tripeptide containing a thiomalonamide moiety was developed. Isothiocyanate derivatives of amino acids react smoothly with 2,2-dimethyl-1,3-dioxane-4,6-dione yielding new thiocarbamoyl Meldrum's acids. Thermal decomposition of this new Meldrum's acid derivatives generate thiocarbamoyl ketenes, which acylate amino acid esters to give pseudo tripeptides.
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Synthesis, structure and properties of novel poly(hydroxyurethane)s obtained by non-isocyanate route
PublicationNon-isocyanate polyurethanes (NIPUs) can be synthesized by polyaddition of five-membered bis(cyclic carbonate)s and primary diamines. NIPUs are an alternative for the commonly used (in the form of foams, elastomers, coatings or fibers) in the industry polyurethanes obtained using toxic and moisture sensitive diisocyanates, polyols and low-molecular weight chain extenders. The main aim of this work was to synthesize non-isocyanate...
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Bioactivation of Konjac Glucomannan Films by Tannic Acid and Gluconolactone Addition
PublicationWound healing is a dynamic process that requires an optimal extracellular environment, as well as an accurate synchronization between various cell types. Over the past few years, great efforts have been devoted to developing novel approaches for treating and managing burn injuries, sepsis, and chronic or accidental skin injuries. Multifunctional smart-polymer-based dressings represent a promising approach to support natural healing...
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The content of conjugated linoleic acid and vaccenic acid in the breast milk of women from Gdansk and the surrounding district, as well as in, infant formulas and follow-up formulas. Nutritional recommendation for nursing women
PublicationFatty acids are some of the most important components of human milk. Polyunsaturated fatty acids (PUFAs) are essential nutrients required for the optimal growth and development of infants, especially the central nervous system, brain and retina. AIM: To determine the conjugated linolenic acid (CLA) and vaccenic acid (VA) content of human breast milk from mothers consuming different diets, and to compare the results with CLA and...
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Atom-economic thiophosphoroselenenylations of C–H acid esters and amides
PublicationThree improved thiophosphoroselenenylation procedures of CHacids, including derivatives of malonic and acetyl-, phosphono-, 4-nitrophenyl- and 3-pyridylacetic acids, have been described and compared to previously reported thiophosphoroselenylation of diethyl malonate using bis(disopropoxyphosphinothioyl)diselenide alone or with the aid of methyl iodide. The use of iodine makes it possible to utilize both equivalents of the selenenylating...
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Chromogenic amides of pyridine-2,6-dicarboxylic acid as anion receptors
PublicationThe synthesis of simple, chromogenic pyridine-2,6-dicarboxylic acid amides, derivates of isomeric nitroanilines and aminonitrophenols, and their ion binding properties are described. The ligands' response to ionic species was examined by naked eye and was studied with the use of UV-Vis spectroscopy in DMSO and its mixture with water. The effect of the localisation and the type of the substituents in aromatic rings were discussed....
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Synthesis and antiproliferative activity of new mycophenolic acid conjugates with adenosine derivatives
PublicationNew conjugates of mycophenolic acid (MPA) and adenosine derivatives were synthesized and assessed as potential immunosuppressants on Jurkat cell line and peripheral blood mononuclear cells (PBMC) from healthy donors. As compared to MPA, all compounds were found to be more active against Jurkat cell line. The antiproliferative activities were compared with MPA and adenosine, in both 2′,3′-O-isopropylidene protected and free hydroxyl...
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Investigation of corrosion behavior of 6060 and 6082 aluminum alloys under simulated acid rain conditions
PublicationInstantaneous impedance changes of 6060 and 6082 type aluminum alloys in pure water, and simulated acid rain poured into the pure water was investigated by dynamic electrochemical impedance spectroscopy (DEIS). In this way, the influence of aluminum content on the corrosion behavior of 6060 and 6082 type aluminum alloys immersed in simulated acid rain was determined. The corrosion rate of the alloy decreased with increasing Al...
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Microcrystalline Cellulose Management in the Production of Poly(ether-urethane)s- Structure, Morphology, and Thermal Characteristic
PublicationIn response to the demand of polymer industry for reducing the use of synthetic chemicals, eco-friendly materials are investigated. In the presented study, bio-based poly(ether-urethane)s were prepared by using microcrystalline cellulose (MCC) and polyether polyol and 1,3-propanediol derived from corn sugar. A step towards sustainability was taken by incorporating bio-based compounds and cellulose, consequently, bio-waste are utilized...
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Tuning of microstructure in engineered poly (trimethylene terephthalate) based blends with nano inclusion as multifunctional additive
PublicationImmiscible blends and their composites are heterogeneous and have variable morphology due to variation in mesophase regions. Tuning, i.e. controlling the phase dimension is important, thereof we report a “super-combo” effect of multiwalled carbon nanotubes (MWCNTs) in poly (trimethylene terephthalate)/polypropylene (PTT/ PP) blend system. MWCNTs act as a good reinforcing agent and compatibilizer in the otherwise immiscible PTT/...
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Thermal properties of poly(vinyl chloride)/polyurethane blends
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Synthesis and properties of UV-curable poly(imideurethane) acrylates.
PublicationOtrzymano światłoczułe poli(imidouretano) akrylany (PIUA) które użyte zostały do wytwarzania światłoczułych kompozycji z dodatkiem reaktywnych rozcieńczalników i różnych fotoinicjatorów. Uzyskane z nich cienkie warstwy polimerowe ulegały usieciowaniu pod działaniem światłaUV w ciągu 10-30 sek. W badaniach fotolitograficznych uzyskano z ich użyciem ścieżki izolacyjne o rozdzielczości 10 mikrometrów. Usieciowane PIUA scharakteryzowano...
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The interference between electrode and poly(ethylene oxide) electrolytes
PublicationSpektroskopia impedancyjna zastosowana została do scharakteryzowania granicy faz elektroda-elektrolit poli(oksyetylenowy) zawierający sole litu. Udział rozpuszczalnika w pojemności wewnętrznej warstwy, Cs(σ), dla CH3(OCH2CH2 )nOCH3 DLA N=4,8,10 oraz dla PMEO [(CH2CH2O)mCH2O]m m=5-10 został wyznaczony z wartości pojemności warstwy sztywnej pomniejszonej o udział metalu CM. Wyznaczono wartość pojemności dipolowej Ci(dip) dla PEO...
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Biodegradation of modified poly(î-caprolactone) in different environments
PublicationPorównano odporność na biodegradację różnych filmów poliepsilon kaprolaktonu w wodzie morskiej z Bałtyku, w roztworze soli, w wodzie morskiej z azydkiem sodu oraz w kompoście z osadem czynnym. Oceniano zmiany ubytku wagi, lepkość właściwości wytrzymałościowe, stopień krystaliczności i morfologię przed i po procesie degradacji. Filmy z dodatkiem środków antypoślizgowych, degradowane w środowiskach naturalnych ulegały rozkładowi...
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Influence of the Type of Amino Acid on the Permeability and Properties of Ibuprofenates of Isopropyl Amino Acid Esters
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The physicochemical properties of 3D materials based on hyaluronic acid modified by tannic acid addition
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Pressure-induced flow processing behind the superior mechanical properties and heat-resistance performance of poly(butylene succinate)
PublicationWe propose a pressure-induced flow (PIF) processing method for the simultaneous enhancement of strength, toughness, and heat resistance of biodegradable poly(butylene succinate) (PBS). The pressure and temperature were systematically adjusted to optimize the tensile strength of PBS. Under the optimized processing conditions, the structured PBS was characterized by relatively high strength of 89.5 MPa, toughness of 21.4 kJ·m−2 ,...
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On the origin of surfaces-dependent growth of benzoic acid crystal inferred through the droplet evaporation method
PublicationCrystal growth behavior of benzoic acid crystals on different surfaces was examined. The performed experiments documented the existence of very strong influence introduced by polar surfaces as glass, gelatin, and polyvinyl alcohol (PVA) on the growth of benzoic acid crystals. These surfaces impose strong orientation effect resulting in a dramatic reduction of number of faces seen with x-ray powder diffractions (XPRD). However,...
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On the origin of surfaces-dependent growth of benzoic acid crystal inferred through the droplet evaporation method
PublicationCrystal growth behavior of benzoic acid crystals on different surfaces was examined. The performed experiments documented the existence of very strong influence introduced by polar surfaces as glass, gelatin, and polyvinyl alcohol (PVA) on the growth of benzoic acid crystals. These surfaces impose strong orientation effect resulting in a dramatic reduction of number of faces seen with x-ray powder diffractions (XPRD). However,...
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On the origin of surfaces-dependent growth of benzoic acid crystal inferred through the droplet evaporation method
PublicationCrystal growth behavior of benzoic acid crystals on different surfaces was examined. The performed experiments documented the existence of very strong influence introduced by polar surfaces as glass, gelatin, and polyvinyl alcohol (PVA) on the growth of benzoic acid crystals. These surfaces impose strong orientation effect resulting in a dramatic reduction of number of faces seen with x-ray powder diffractions (XPRD). However,...