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Search results for: CAST POLYURETHANES
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Renewable Resources for Polyurethanes and Polyurethane Composites: A Review
PublicationEach year, more than two million tons of polyurethane is produced in the EU by reacting isocyanates with polyols made from fossil fuel. In addition, there are appreciable quantities of petroleum based functional additives applied in the industry nowadays for both polyols and polyurethane materials. It is therefore of key importance to develop sustainable economically viable polyols with enhanced functionalities, and thereby reducing...
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Polyurethanes modified with natural polymers for medical application. I. Polyurethanes/ Chitosan and polyurethane/collagen.
PublicationFor over three decades polyurethanes (PUR or PU) have been reported for application in a variety of medical devices. These polymers consist of hard and soft segments, which allow for more subtle control of their structure and properties. By varying the composition of the different segments, properties of PURcan be tuned up for use in many areas of medicine. Recently there is a great interest in modification of biomedical PUR with...
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Polyurethanes modified with natural polymers for medical application. Part II. Polyurethane/gelatin, polyurethane/starch, polyurethane/cellulose
PublicationThis paper is a literature overview of biomedical PUR modifications with natural polymers such as starch, cellulose and gelatin. Properties like biodegradability and biocompatibility of modified PUR cause that these materials may be used as wound dressings, tissue scaffolds, tissue implants and also vascular grafts.
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Polyurethanes modified with natural polymers for medical application. Part I. Polyurethane/chitosan and polyurethane/collagen
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Thermoplastic polyurethanes with glycolysate intermediates from polyurethane waste recycling
PublicationThe polyol is a major component in polyurethane formulations and therefore introducing to the formulation recycled polyol (obtained during decomposition process) allows decreasing the usage of pure petrochemical components. In this work, thermoplastic polyurethanes were prepared using various mixtures of a petrochemical macrodiol poly(ethylene-butylene adipate)diol (PEBA) and a recycled glycolysate intermediate, called glycolysate...
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Thermal properties of polyurethanes synthesized using waste polyurethane foam glycolysates
PublicationW pracy przedstawiono wyniki analizy termicznej (DMTA i TG-FTIR) glikolizatów i otrzymanych z nich poliuretanów. Glikolizaty uzyskiwano w reakcji odpadowej pianki poliuretanowej z 1,6 heksametylenodiolem (HDO) przy różnym stosunku masowym pianki do HDO (1:1 - 10:1). Poliuretany syntezowano metodą dwuetapową z prepolimeru (diizocyjanian MDI + glikolizat), który przedłużano handlowym małocząsteczkowym glikolem.
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Kinetics of cross-linking processes of fast-curing polyurethane system
PublicationThis work focuses on the application of thermal analysis and kinetics investigations to analyze chemical processes during cross-linking of the complex fast-curing polyurethane system. Non-isothermal Differential Scanning Calorimetry (DSC) measurements were performed for both stoichiometric mixtures of polyol and isocyanate component and for mixture with large isocyanate excess. Isoconversional methods were used to calculate initial...
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Polyurethanes
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Polyurethanes
PublicationThe chapter content is devoted to Polyurethanes and consists of the following items: general characteristics of polyurethanes, raw materials used in the synthesis of crosslinked polyurethanes, synthesis and crosslinking reactions of polyurethanes, morphology of liniear and branched PU, manufacturing methods and functional properties.
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Polyurethanes
PublicationHandbook of Thermoset Plastics, Fourth Edition provides complete coverage of the chemical processes, manufacturing techniques and design properties of each polymer, along with its applications. This new edition has been expanded to include the latest developments in the field, with new chapters on radiation curing, biological adhesives, vitrimers, and 3D printing. This detailed handbook considers the practical implications of using...
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Cast polyurethanes obtained from reactive recovered polyol intermediates via crude glycerine decomposition process
PublicationIn this work, the possibility of applying intermediates from polyurethane waste recycling in polyurethane synthesis was presented. Polyurethanes were synthesised in a two-step method using a mixture of petrochemical polyol and glycerolysate, used as a reactive component, 4,4-diphenylmethane diisocyanate (MDI) and 1,4-buthanediol (BD). Glycerolysates were produced during decomposition of polyurethane elastomer by crude glycerine...
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Novel Cast Polyurethanes Obtained by Using Reactive Phosphorus-Containing Polyol: Synthesis, Thermal Analysis and Combustion Behaviors
PublicationPhosphorus-containing polyol applications in polyurethane synthesis can prevent volatilization of flame retardants and their migration on the surface of a material. In this work, novel cast polyurethanes were prepared by a one-step method with the use of different amounts of phosphorus-containing polyol, 4,4′–diphenylmethane diisocyanate and 1,4-butanediol. The chemical structure, thermal, physicochemical and mechanical properties...
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Sizes and Shapes of Sea Ice Floes Broken by Waves–A Case Study From the East Antarctic Coast
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Recycling of Polyurethanes
PublicationPolyurethane waste can be recycled by mechanical methods (i.e., grinding and applying as a filler or pressing with a bonding agent) and chemical methods (mainly by e.g., glycolysis, hydrolysis, or aminolysis). There is also possibility to the recover energy from polyurethanes waste (by incineration, gasification, and pyrolysis).
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RECENT DEVELOPMENTS IN POLYURETHANE FOAMS CONTAINING LOW-COST AND PRO-ECOLOGICAL MODIFIERS
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A recent developments in polyurethane foams containing a low-cost and pro-ecological modifiers
PublicationDiversity of the polyurethane (PU) foams applications cause that investigation of the relationships between their structure and properties is currently very popular topic among the many research institutions and companies. At the turn of the last years many scientific papers about PU foams and their composites were published. The one of the main research trends in this field is related to the reduction of production costs of...
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Isocyanate-Free Polyurethanes
PublicationIsocyanate-free polyurethanes (also called non-isocyanate polyurethanes, or NIPUs) are alternatives to the conventional (commercially used) polyurethanes synthesized using di- or polyisocyanates, polyols, and chain extenders with low molecular weight. The major routes of NIPUs’ synthesis involve polyaddition of cyclic carbonates and di- or polyamines, polycondensation of carbamates, and diols. The most important intermediates are...
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Non-isocyanate Polyurethanes
PublicationThe main aim of this chapter is to present a general overview of the NIPU synthesis method (i.e., polycondensation and polyaddition), and to describe structure and properties of selected intermediates and final polymeric products. The focus is on five-membered ring cyclic carbonate intermediates, which were obtained by cycloaddition of carbon dioxide to selected glycidyl ethers and thiol-ene coupling of unsaturated cyclic carbonates...
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Recycling of Polyurethanes Containing Flame-Retardants and Polymer Waste Transformed into Flame-Retarded Polyurethanes
PublicationThe growing number of polyurethanes (PUs) produced every year has developed methods for their mechanical and chemical recycling which yield valuable products like substitutes for commercial polyols or flame-retardants. PUs can be produced in different shapes and forms (i.e., elastomers, flexible or rigid foams, coatings, etc.) using several different components (i.e., di- or polyisocyanates, ester- or ether-based polyols, low-molecular...
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Properties of PA6/thermoplastic polyurethane and PA6/polyurethane nanocomposite blends
PublicationPrzedstawiono wyniki badań właściwości i struktury mieszanin i nanokompozytów układów PA6/termoplastyczny poliuretan. W przypadku nanokompozytów wprowadzano nanonapełniacz w postaci montmorylonitu. Zbadano właściwości termiczne i wytrzymałościowe oraz omówiono wyniki analiz strukturalnych, otrzymanych z dyfrakcji rentgenowskiej i mikroskopii elektronowej.
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Polyurethanes as a carrier of drugs for gentamicin
PublicationGentamicin is one of the most popular drug and is widely used due to its antibiotic properties. 3% of world production of polyurethanes (PU) is dedicated to biomedical applications, where they can serve are parts of orthopedic prosthesis or artificial organs, disposable medical devices, wound and burn dressing, contact lenses among others. In the study, to obtain drug carriers, a combination of these two materials were prepared...
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Degradation of polyurethanes in sea water
PublicationOceniono degradowalność różnych poliuretanów w wodzie morskiej Bałtyku. Porównano te dane z wynikami stopnia degradacji poliuretanów w wodzie morskiej z dodatkiem azydku sosowego. Ocenę stopnia degradacji przeprowadzano na podstawie pomiarów zmian masy, właściwości mechanicznych i morfologii przed i po procesie degradacji. Wykazano, że różna podatność na degradację poliuretanów w wodzie morskiej związana jest z ich odmiennym stopniem...
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Novel Research on Biomedical Polyurethanes
PublicationThe variety of mechanical properties characterizes properly designed PURs. They may be biocompatible and reveal compatibility with blood, making them attractive materials for the fabrication of tissue scaffolds; however, like all synthetic materials, PURs don’t reveal sufficient biocompatibility. PURs may undergo certain chemical modifications (e.g., 1,4:3,6-dianhydro-D-sorbitol, ascorbic acid (AA), growth factors, covering with...
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Development of polyurethanes for bone repair
PublicationThe purpose of this paper is to review recent developments on polyurethanes aimed at the design, synthesis, modifications, and biological properties in the field of bone tissue engineering. Different polyurethane systems are presented and discussed in terms of biodegradation, biocompatibility and bioactivity. A comprehensive discussion is provided of the influence of hard to soft segments ratio, catalysts, stiffness and hydrophilicity...
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Synthesis and characterisation of polyurethane elastomers with semi-products obtained from polyurethane recycling
PublicationIn this work polyurethane elastomers were synthesised by using different mixtures of a petrochemical and glycerolysate polyols and 4,4-diphenylmethane diisocyanate (MDI). Glycerolysate polyol was produced from polyurethane foam decomposition using crude glycerine as a decomposition agent. The structure and thermal properties of obtained semi-product were similar to the polyol used in the synthesis of original foam. Glycerolysate...
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Polyurethanes containing organically modified clay
PublicationW pracy zaprezentowano wyniki badań dotyczące wpływu nowego, krajowego, modyfikowanego glinokrzemianu (BZ-COCO) na elastomery poliuretanowe. Dla otrzymanych układów określono podstawowe właściwości mechaniczne, termiczne oraz przeprowadzono analizę struktury.
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Novel Polyurethanes as Antifouling Paint Matrices
PublicationThe new poly(ester-ether urethane)s (PEEUR) were prepared in two stage synthesis from formerly obtained oligo(alkylene ester-ether)diols (OAEE) and 4,4‘-diphenylmethane diisocyanate (MDI). PEEUR samples were subjected to crosslinking with styrene in the presence of radical polymerization initiators: methyl ethyl ketone peroxide (MEKPO) or cobalt 2-ethyl cyclohexanoate (EtHCo). Crosslinked PEEUR were characterized by their physicochemical...
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Non-Isocyanate-Based Waterborne Polyurethanes
PublicationNon-isocyanate polyurethanes (NIPUs) are a greener alternative for the conventional polyurethanes synthesized using toxic and moisture-sensitive di- or polyisocyanates. The most often described method of NIPU synthesis involves the reaction of five-membered cyclic carbonates with amines, and resulting polymers containing primary and secondary hydroxyl groups (so they are also known as polyhydroxyurethanes), which can be further...
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Polyurethanes for Coating, Adhesives, and Other Applications
PublicationAn interesting group of polyurethane (PU) materials are coatings, adhesives, sealants, and thickeners. A wide base of raw materials and various methods of PU synthesis allows production of materials with a wide range of properties that can be commonly used in many industries. This chapter describes the main types of PU coatings and adhesives and special application PUs and the methods of their production. The materials described...
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Bioactive polyurethanes applied as a surgical implants
PublicationSynthetic materials are applied in many branches of the industry, i.a. in medicine as a casing of apparatus, elements of artificial organs (hearts, blood vessels), catheters, wound healings, intra aortic balloons, mammary implants to mention but a few. Polymeric material used in such applications must be distinguished by a good biocompatybility. Since many years extensive research are employed to develop a new polymers that can...
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Evaluating the Cost of Personnel Activities in Cybersecurity Management: A Case Study
PublicationThe methods of cybersecurity costs' evaluation are inclined towards the cost of incidents or technological acquirements. At the same time, there are other, less visible costs related to cybersecurity that require proper recognition. These costs are associated with the actions and the time spent by employees on activities connected to cybersecurity management. The costs form a considerable component of cybersecurity expenditures,...
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Case Study of Stray Current Corrosion of Tall Ship Mast
PublicationNowadays, in the present technical civilization there are numerous complex technical systems that may generate various hazards. Large transport units like ships can be considered as the most dangerous systems. Therefore, it is important to eliminate all possible hazards, especially for ship crewmembers. Destruction of ship structural components caused by vast corrosion is one of these hazards. Usually, its activity leads to a decrease...
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Characteristics of the conductivity of polyurethane nanocomposite
PublicationW opracowaniu tym przedstawiono właściwości mechaniczne oraz przewodnictwo jonowe otrzymanych nanokompozytów poliuretanowych. KOmpozyty te były otrzymane przy wykorzystaniu wytłaczarki dwuślimakowej. POddano je badaniom wytrzymałościowym, spektroskopii impedancyjnej, spektroskopii w podczerwieni oraz badaniom dynamiczno - mechanicznym (DMA)
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Shape-Memory Polyurethane Polymers
PublicationPolyurethanes (PUs) are one of the most widely used polymers in research and industry. They can be synthesized from chemical sources and natural sources. PUs are a very useful class of polymers and exhibit many desirable properties that can be exploited in various applications. PUs are formed by the reaction between polyols and isocyanates. A wide variety of polyols and isocyanates are available for synthesis, and hence we can...
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Gelatin-Modified Polyurethanes for Soft Tissue Scaffold
PublicationRecently, in the field of biomaterials, which are being designed for soft tissue scaffolding, is growing the interest of their modification with natural polymers. Synthetic polymers are often hard, not easy to process and they do not possess fine biodegradable profile. From the other hand natural polymers are biocompatible, but weak when used alone. The combination of natural and synthetic polymers gives the suitable properties...
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Morphology of polyurethanes revisited by complementary AFM and TEM
PublicationPrzedmiotem badań mikroskopowych TEM i AFM były lane segmentowe poliuretany o zawartości 30 i 50% segmentu sztywnego. Stwierdzono obecność sferolitów (poziom mikrometrów), fibryl i globul. Ponadto zastosowanie AFM pozwoliło na zbadanie nanomorfologii badanych poliuretanów. Zaobserwowano krótkie, cylindropodobne domeny segmentów sztywnych rozproszone w matrycy segmentów giętkich.
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Raman microscopy in the studies of microphase-separated polyurethanes.
PublicationPorównano możliwości badawcze różnych odmian spektroskopowych do analizy po-limerów. Podano przykłądy wykorzystania połączonych technik mikroskopowych ispektroskopowych do badania polimerów wielofazowych. Na tej podstawie wyka-zano zasadność zastosowania po raz pierwszy mikroskopii Ramana w badaniachwielofazowych poliuretanów. Wykazano różnice składu chemicznego poszczegól-nych elementów mikromorfologii wielofazowych, segmentowych...
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Degradation of polyurethanes in Compost Under Natural Conditions
PublicationThe estimation of degradibility of different polyurethanes under natural weather depending conditions in compost pile was the subject of the studies. The incubation of polymer samples took place for a period up to 24 months. The characteristic parameters of the compost: temperature, pH, moisture content, and activity of dehydrogenasis were monitored and their influence on degradation of polyuiretahnes was discussed. The compostability...
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The influence of synthetic polyhydroxybutyrate on selected properties of novel polyurethanes for medical applications. Part I. Polyurethanes with aromatic diisocyanates in hard segments
PublicationZsyntetyzowano poliuretany (PUR) z udziałem 37% segmentu sztywnego uzyskanego na etapie przedłużania łańcucha prepolimeru w reakcji 4,4â-diizocyjanianu difenylometanu (MDI) z 1,4-butanodiolem (1,4-BD). Segmenty giętkie wytworzonych PUR były zbudowane z poli([R,S]-3--hydroksymaoelanu) (a-PHB) i polikaprolaktonodiolu (PCL) lub z a-PHB i polioksytetrametylenodiolu(PTMG). Zbadano wpływ obecności w łańcuchu PUR syntetycznego a-PHB...
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Estimating the Cost of Cybersecurity Activities with CAsPeA: A Case Study and Comparative Analysis
PublicationContemporary approaches to the estimation of cybersecurity costs in organisations tend to focus on the cost of incidents or technological investments. However, there are other, less transparent costs related to cybersecurity management that need to be properly recognised in order to get a complete picture. These costs are associated with everyday activities and the time spent by employees on cybersecurity-related actions. Such...
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Post-peak behaviour of CFST columns
PublicationArtykuł dotyczy zachowania pokrytycznego słupów CFST. Parametrami zmiennymi w badaniach są: wysokość słupów, grubość stalowego płaszcza, wytrzymałość betonu i stali, przyczepność między stalowym płaszczem a betonowym rdzeniem oraz sposób przykładania obciążenia. W artykule dokonano analizy wpływu tych parametrów na zachowanie pokrytyczne badanych słupów.
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Fabrication of polyurethane and polyurethane based composite fibres by the electrospinning technique for soft tissue engineering of cardiovascular system
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Fabrication of polyurethane and polyurethane based composite fibers by the electrospinning technique for soft tissue engineering of cardiovascular system
PublicationElectrospinning is the unique technique, which provides forming of polymeric scaffolds for soft tissue engineering, which include tissue scaffolds for soft tissues of cardiovascular system. Such artificial soft tissues of cardiovascular system may possess mechanical properties comparable to native vascular tissues. Electrospinning technique gives the opportu nity to form fibres with nm- to μm-scale in diameter. The arrangement...
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Shape memory thin films of Polyurethane: Does graphene content affect the recovery behavior of Polyurethane nanocomposites?
PublicationThin nanocomposite films of polyurethane have received remarkable attention due to their shape memory properties. As most of the reports focus on the beneficial aspects of the presence of nanofillers such as graphene nanoplatelets (GNPs) introduced into shape memory polymers, some research results reveal the opposite trend. The polyether/polyester-based polyurethane was synthesized through a condensation polymerization and the...
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Case study 1.2C: Road infrastructure cost in Poland, Annex to Deliverable D3, Marginal cost case studies for road and rail transport. GRACE. Funded by Sixth Framework Programme.
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A review: Fabrication of porous polyurethane scaffolds
PublicationThe aim of tissue engineering is the fabrication of three-dimensional scaffolds that can be used for the reconstruction and regeneration of damaged or deformed tissues and organs. A wide variety of techniques have been developed to create either fibrous or porous scaffolds from polymers, metals, composite materials and ceramics. However, the most promising materials are biodegradable polymers due to their comprehensive mechanical...
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The structure and conductivity of solid polyurethane electrolyte
PublicationPrzedstawiono badania właściwości i struktury stałych elektrolitów poliuretanowych. Otrzymano je z prepolimeru zsyntezowanego z MDI oraz PTMG. Jako przedłużacz łańcucha wykorzystano butanodiol. W celu poprawy przewodnictwa domieszkowano poliuretan solami LiClO4 lub LiCl, które wprowadzono za pomocą wytłaczarki dwuślimakowej. Otrzymane elektrolity poddano badaniom: wytrzymałościowym, twardości, spektroskopii FTIR oraz przewodnictwa...
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Morphology and degradation of polyurehanes in different environments.
PublicationW pracy przedstawiono wyniki badań degradacji poli(estro-uretanów) (PEsUA i PEsUB) oraz poli(etero-uretano-mocznika)(PEtUU) w roztworach buforowych o zmiennym pH (168 godz., 70 oC), w środowisku trypsyny (37 oC, 1 m-c), Aspergillys niger (12 m-cy), kompoście z osadem czynnym (12 m-cy) i w wodzie morskiej (12 m-cy). Analizowano zmiany w morfologii i właściwościach fizykomechanicznych. Ustalono następujące sekwencje w zmianach zależności...
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The structure and conductivity of solid polyurethane electrolytes
PublicationPrzedmiotem badań były stałe elektrolity poliuretanowe otrzymane w wyniku syntezy MDI, PTMO, BD oraz TG z DMPA. Domieszkowanie LiCl zostało wykonane przy zastosowaniu przedłużacza. Badano przewodnictwo jonowe otrzymanych elektrolitów stałych przy użyciu technik stało i zmiennoprądowych. Przedstawiono również wyniki badań z wykorzystaniem technik mikroskopii elektronowej oraz FTIR-ATR.
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Clays as Inhibitors of Polyurethane Foams’ Flammability
PublicationPolyurethanes are a very important group of polymers with an extensive range of applications in different branches of industry. In the form of foams, they are mainly used in bedding, furniture, building, construction, and automotive sectors. Due to human safety reasons, these applications require an appropriate level of flame retardance, often required by various law regulations. Nevertheless, without the proper modifications,...