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PL
Jednym z kierunków rozwoju technologii materiałowych jest nanotechnologia rozumiana jako dziedzina zajmująca się zastosowaniem nanododatków do wytwarzania nowych materiałów oraz ich wpływem na parametry modyfikowanych materiałów. W ostatnich latach nanotechnologia wkracza do technologii modyfikacji asfaltów stosowanych do wykonania nawierzchni drogowych. W artykule przedstawiono stosowane obecnie w budownictwie drogowym nanododatki oraz ich właściwości.
EN
One of the direction in the development of the material technology is nanotechnology, understood as using nanoadditives to create new materials and the impact of the additives on the properties of modified materials. In recent years nanotechnology is increasingly used in the modification of the bitumen used in the asphalt pavements. The article presents presently used nanoadditives and their properties.
EN
Purpose: The article focuses on the production of polymer nanofibres from poly(lactic acid) using the electro-spinning method, i.e. the technique of forming fibres in an electrostatic field. The main aim of the publication was to analyse the influence of the distance between electrodes on the morphology of one-dimensional polymeric materials obtained. Design/methodology/approach: In the practical part of the study solutions of polylactide in acetone and a mixture of chloroform/dimethylformamide (DMF) were produced. After 72 hours of mixing, no homogeneous solutions were obtained, therefore a solution consisting of a polylactide dissolved in chloroform was prepared, to which dimethylformamide was added in order to dilute the mixture. The morphology of the nanostructures obtained was analysed by means of a scanning electron microscope (SEM) equipped with an X-ray energy dispersion spectrometer (EDS), which allowed to analyse the chemical composition of the nanofibres produced. The electro-spinning method used to obtain fibres is characterized by high versatility - it gives the possibility to produce fibres from a wide range of polymers. Electro-spinning is also an economic method, and spinned fibres have a wide application potential. Findings: Nanofibres obtained by electro-spinning from the previously produced solution, regardless of the distance between the nozzle and the collector (10 or 20 cm) did not show any significant discrepancies in the values of measured diameters. Fibres obtained at increased distance between electrodes (20 cm) are characterized by a smaller average diameter value, but the difference is small, fluctuating between 48-49 nm. In the case of the sample formed during electro-spinning at the distance of the nozzle - collector equal to 10 cm and the sample produced at the distance doubled, no defects in the structure of the obtained nanofibres were observed. The analysis of topographic images of surfaces produced in the course of nanostructures' work did not show any significant influence of the distance between the nozzle and collector on the diameter of fibres. No defects in the structure of one-dimensional polymer materials obtained allowed to state that the distance between the nozzle and the collector in the range of 10-20 cm is the optimal parameter of the electro-spinning process allowing to obtain smooth, untangled fibres. Practical implications: The fibrous polymer mats obtained during the electro-spinning process of polylactide can be used as protective clothing materials, as drug delivery systems, as tissue scaffolding and as filtration membranes. Originality/value: At present, there are few articles in the literature on the electrospinning process, due to the fact that it is a constantly developing matte for the production of nanofibres. Moreover, most of the research focuses on fibres obtained from nonbiodegradable polymers, which do not have the advantages of fibres obtained from polylactide.
3
Content available remote Electrospinning of PAN and composite PAN-GO nanofibres
EN
Purpose: The aim of this study was to present the influence of used reinforcement phase – graphene oxide (GO) and the electrospinning process parameters (the distance between the nozzle and collector) on the morphology and the structure of the obtained composite PAN-GO nanofibres. Design/methodology/approach: To produce pure polymer nanofibers, a 10% (wt.) electrospinning solution the polyacrylonitrile (PAN) was dissolved in N, N-dimethylformamide (DMF). The spinning solution used for electrospinning PAN-GO composite fibres was made by dissolving the PAN in a mixture of GO and DMF. By changing the configuration of the distance between the nozzle and collector (10 and 20 cm) and maintaining the remaining parameters (solution flow rate and potential difference between the electrodes), four samples in the form of nanofibrous mats were made. In order to identify the structure and morphology of the reinforcing phase, X-ray microanalysis (EDX) and scanning electron microscopy (SEM) were performed. In addition, the structure of graphene oxide microparticles was investigated by a Raman spectrometer. In order to determine the influence of the distance between the nozzle and the collector used in the electrospinning process and the addition of the reinforcing phase to the morphology and structure of the obtained PAN polymer nanofibres and PAN-GO composite nanofibres, they were examined using SEM. The analysis of the chemical composition of PAN and PAN-GO fibres was carried out using X-ray microanalysis. Findings: The morphology and structure analysis indicated that polymer nanofibres PAN for both the distances between the nozzle and the collector show no structural defects and presented same diameter over the entire length of the fibre. Nanofibres with the addition of GO obtained at both distances between the electrodes, showed defects in the form of beads. In addition, it was observed that with increasing distance between the nozzle and collector the diameter of obtained nanofibres is smaller for both pure PAN and composite PAN-GO samples. Research limitations/implications: The paper is the basis for further research in the field of the use of PAN-GO composite nanofibres as water purification materials. Originality/value: The electrospinning method can be an alternative to conventional methods for the production of filtering membranes due to the ease of carrying out the process and the fact that a material with a high specific surface area is obtained.
EN
The article presents an overview of electrospinning process development from the first investigations in the field of behaviour of liquids in an electrostatic field to the electrospinning methods and investigations in the 21st century. The article presents the history of electrospinning process development, the main problems that are solved, and also indicates the gaps in the field of standardisation of nanofibrous web structure measurement and estimation. There are a lot of works in which authors analyse influences of various parameters on the electrospinning process or on the structure of electrospun web, whereas the majority of them do not analyse the quality of structure using mathematical criteria. Such a situation leads to different conclusions and makes it impossible to compare various works by different authors. Despite numerous studies in electrospinning, investigations in the electrospun nanofibrous web estimation are not sufficient. Until now, a unique standard method for measuring and estimating the fibre diameter and web porosity has not been developed. The necessity of such a method and standards is obvious, and the lack of such a standard could have a negative influence on the electrospun product introduction into the market.
EN
Textile materials with an electrospun nanofibrous web can be used fo ar wide range of applications, including medicine and health care. In this research, polyamide-6 and hyaluronic acid were used for the development of a nanofibrous web via electrospinning. Hyaluronic acid is one of the most interesting ingredients used in skin care. It is very important that the electrospun polyamide-6 nanofibrous structure binds nanoparticles of hyaluronic acid not covering the surface of these particles. The main goal of this work was to develop an electrospun nanofibrous polyamide-6 web with hyaluronic acid which can be used for health care and/or cosmetology A. polyamide-6 nanofibrous web with hyaluronic acid was successfully developed via electrospinning. The presence of hyaluronic acid in the nanoweb was confirmed after web treatment with hot (95%) water. Hyaluronic acid was transported from the spinning solution to the electrospun web, was not isolated from the environment by polyamide-6, and could interact with human skin.
PL
Materiały tekstylne z elektroprzędzionym runem znajdują szeroki zakres zastosowań w produkcji materiałów do zastosowań medycznych. W pracy wytworzono za pomocą elektroprzędzenia runo z poliamidu 6 i kwasu hialuronowego. Kwas hialuronowy jest jednym z najbardziej obiecujących składników stosowanych w pielęgnacji skóry. Istotne jest, aby struktura nanowłókna poliamidowego wiązała nanocząsteczki kwasu hialuronowego, nie pokrywając powierzchni tych cząstek. Głównym celem pracy było opracowanie runa poliamidowego z kwasem hialuronowym, które może być zastosowane w wyrobach medycznych i/lub kosmetologii.
EN
Fiber diameter and its distribution are one of the most important parameters related with the quality of electrospun web. The diameter of electrospun nanofibres is not uniform and the histograms of values are usually distributed differently. Analysis of literature sources showed that sometimes the distribution curves are similar to normal (Gaussian) distribution. Sometimes the distribution shapes are sophisticated and do not resemble this one. The problem arises because it is impossible to compare the average values of different measurement distributions, and a method with possibilities to compare the different results for estimation of nanofibre web quality is necessary. Yet, till now no standardized method for measurement of the diameter and evaluation of the distribution has been created. In this article, various distributions from literature sources and those of nanofibre diameter obtained during own experiments were analysed. Values of the nanofibre diameter are described by normal (Gaussian) and compound mathematical distributions. It was decided that the skew of distribution along with other characteristics can be used as criterion for web estimation and the diameter of nanofibres can be described by skewed normal (Gaussian) distribution when the coefficient of skewness is less than 0.5. The possibilities of estimation by compound distribution from a few normal distributions must be checked when the coefficient is higher.
PL
Średnica włókien i jej rozkład są jednym z najważniejszych parametrów związanych z jakością elektroprzędzionego runa. Średnica elektroprzędzionych nanowłókien jest zróżnicowana, jak i histogramy średnic, które są zwykle zróżnicowane. Analiza literatury wykazała, że czasami rozkłady są podobne do rozkładów normalnych. Czasami jednak rozkłady są bardziej skomplikowane i nie przypominają rozkładów Gaussowskich. Problem powstaje ponieważ jest niemożliwe porównanie średnich wartości średnic wynikających z rożnych pomiarów. Pożądane jest dysponowanie metodą umożliwiającą porównanie wyników uzyskanych przez rożnych badaczy. W artykule rozważono rożne rozkłady przedstawione w literaturze przedmiotu, jak również uzyskane przez autorów tego opracowania podczas własnych badań. Uzyskane rozkłady przedstawiono poprzez proste rozkłady normalne oraz rozkłady złożone. Stwierdzono, że skośność rozkładu plus dodatkowe parametry mogą być stosowane jako kryterium dla ocen elektroprzędzionego runa. Stwierdzono, że średnica nanowłókien może być określona przez skośny rozkład normalny kiedy współczynnik skośności jest mniejszy niż 0.5. Możliwość oceny rozkładu średnic poprzez złożone rozkłady normalne należy przeprowadzić kiedy współczynnik skośności jest wyższy.
PL
Celem opisywanych badań była ocena wpływu cieczy jonowej należącej do grupy czwartorzędowych soli amoniowych, na właściwości biobójcze nanowłókien z polimeru PLA [poli(kwas mlekowy)] oraz PHB [poli(3-hydroksymaślan)]. Nanowłókna w postaci włókniny wytworzono za pomocą elektroprzędzenia z roztworu. Oba zaproponowane polimery termoplastyczne są nietoksyczne, biodegradowalne oraz biokompatybilne, ale nie wykazują aktywności biologicznej. Właściwość tę zaplanowano nadać nanowłóknom wykorzystując w tym celu ciecz jonową – azotan didecylodimetyloamoniowy [DDA][NO3], którą wprowadzono do roztworów poszczególnych polimerów przed procesem elektroprzędzenia. Przeanalizowano wpływ dodatku czwartorzędowej soli, zarówno na przebieg procesu elektroprzędzenia jak i na właściwości otrzymanych nanowłókien. Wykonano ocenę podatności otrzymanych nanowłókien na działanie grzybów pleśniowych poprzez ocenę stopnia wzrostu mikroorganizmów na badanych próbkach. Otrzymane nanowłókna poddano również ocenie mikroskopowej pod kątem ewentualnych zmian w strukturze włókien elementarnych z wykorzystaniem skaningowego mikroskopu elektronowego (SEM). Zbadano też parametry termiczne modyfikowanych nanowłókien, wyznaczając szybkość wydzielania ciepła w zależności od temperatury za pomocą mikrokalorymetru (PCFC), oraz oceniono możliwości zastosowania otrzymanych nanowłókien w procesie filtracji, wyznaczając parametry efektywności filtracji, spadku ciśnienia oraz współczynnik jakości otrzymanych filtrów.
EN
The aim of this study was to evaluate the effect of the ionic liquid belongs to quaternary ammonium salts on biocidal properties of PLA [poly(lactid acid)] and PHB [poly(3-hydroxybutyrate)] nanofibres. Nanofibres in non-woven form were prepared by electrospinning process. Both of these polyesters are non-toxic, biodegradable and biocompatible thermoplastics with high potential applications but they do not possess their own biological activity. The study was included the achievement of this activity by incorporating substances with antimicrobial properties. For this purpose the ionic liquid was selected. Didecyldimethylammonium nitrate [DDA][NO3] was added to the electrospinning solution of several polymers before electrospinning process. The influence of the quaternary salt addition on the course of electrospinning process and the nanofibres properties were observed. The evaluation of susceptibility of obtained nanofibres to mould fungi was made by assessing the degree of microbial growth on the samples surface. The morphology of the obtained nanofibres was characterized by scanning electron microscopy (SEM) to evaluate the nanofibre structure. The thermal parameters of modified nanofibers were also studied, setting the heat release rate depending on the temperature using microcalorimeter (PCFC). Also evaluated the applicability of the obtained nanofiber in the filtration process, setting the parameters of the filtration efficiency, pressure drop and the quality factor of the obtained filters.
EN
In recent times, electrospinning has become a well known and widely investigated process used for manufacturing nano or/and micro fibres with electrostatic forces between two electrodes. Various additives such as silver, starch, copper, etc. are used in electrospinning to achieve specific properties. Amber is a natural material which has a positive influence on human health and wound healing. However, no information about the electrospinnig of amber particles has been found. In this paper, the possibility of electrospun nanofibrous web formation via electrospinning equipment (NanospiderTM) from poly(vinyl alcohol) solution with solid particles of Baltic amber is presented. It was determined that the maximum size of amber particles which can be transferred from the solution to the electrospun web is around 50 μm, while the probable optimal size of amber particles for electrospinning is below approximately 10 μm.
PL
W ostatnich latach elektroprzędzenie znalazło zastosowanie i zostało opisane w literaturze jako proces dla wytwarzania nano i mikro włókien dla produkcji materiałów do zastosowań medycznych. Stosuje się różnego rodzaju modyfikujące dodatki jak srebro, miedź, skrobia dla uzyskania specyficznych właściwości. Bursztyn jest naturalnym materiałem wywierającym korzystny wpływ na zdrowie człowieka i gojenie ran. Jednakże, nie stwierdzono żadnych informacji dotyczących zastosowania cząstek bursztynu przy elektroprzędzeniu. W przedstawionej pracy rozpatrzono możliwość produkcji nanowłóknistych run poprzez przędzenie z roztworu PVA zawierającego dodatek cząstek bursztynu z zastosowaniem urządzenia Nanospider. Największe z cząstek bursztynu, które znalazły się w wyprzędzionych włóknach miały 50 μm, uważa się jednak, że optymalnym rozmiarem cząstek bursztynu są cząstki poniżej 10 μm.
9
Content available remote Mechanical Properties Of Traditional And Nanofibre Textiles
EN
This study deals with a comparison of mechanical properties of a conventional yarn and a textile from nanofibres. The conventional yarn represents the textile objects with high degree of orientation of fibres and the textile from nanofibres represents the textile objects with low degree of orientation of fibres. The theoretical section is concerned with the issue of internal structure of plied yarn and resulting differences in the orientation and straightening of fibres and in utilisation of deformation properties of fibres in comparison to the referred nano textile. The experimental section describes the manner of realisation of both static and dynamic tests of conventional yarn and strips of nanofibres. The results show differences in the mechanical properties of conventional yarn and textile strip from nanofibres under static and dynamic loading conditions. The processing technology of conventional yarn has been verified in the long term. But textiles from nanofibres are a relatively new material and mechanical properties of the detected differences point out possible problems with their behaviour during standard technological processes.
EN
A study of the manufacturing and characterisation of poly (vinyl alcohol) (PVA) nanofibre mats reinforced with microcrystalline cellulose (MCC) is presented. Results obtained from Attenuated Total Reflection Fourier Transform Infrared (ATR-FTIR) spectrometry and Scanning Electron Microscopy (SEM) of the products are discussed and interpreted. PVA nano-fibre mats reinforced with MCC nano-whiskers (CNWs) were prepared from aqueous PVA solutions by NanospiderTM high-voltage electro-spinning on NS Lab 200 (Elmarco) equipment with a circular cylinder as the emitting electrode. PVA/CNWs mats of a modal nano-fibre diameter of 300 nm and average diameter within the range from 350 to 294 nm were obtained by the electro-spinning technique. Solution parameters, such as the content of CNWs in the solution and PVA concentration and viscosity were varied in an attempt to produce possibly finer cellulose nano-fibres.
PL
Przedstawiono badania dotyczące wytwarzania i charakterystyki nanowłókien z PVA wzmocnionych mikrokrystaliczną celulozą. Włókna otrzymywano za pomocą elektroprzędzenia przy zastosowaniu urządzenia Nanospider i formowania runa. Włókna badano za pomocą spektroskopii ATR-FTIR i elektromikroskopii skaningowej SEM. Uzyskano włókna o modalnej średnicy 300 nm i średniej w zakresie 294-350 nm. W celu uzyskania możliwie najcieńszych włókien stosowano rożne warunki przędzenia i stężenia roztworu przędzalniczego.
11
Content available remote Evaluation of Structure Quality of Web from Electrospun Nanofibres
EN
Electrospinning is remarkably a simple and versatile method for producing nanofibres. The diameter of nanofibres can vary from 10 nm to >1000 nm. In electrospinning, most of the attention is focused on producing fibres with a uniform diameter. It is very important to understand how the diameter and its distribution vary with the materials used and the processing parameters. An analysis of literature sources has shown that the distribution curves of the diameters obtained are very complex and do not resemble normal distributions, while they do more closely correspond to those of compound distributions. The goal of this article is to analyse the distributions of the nanofibre diameters and to propose a new method for the evaluation process of nanofibres and the quality of a nanofibre web. The uniformity of structure and the quality of nanofibres web must be described by average values. The peaks of modal values and the percentage quantity of them must be used for evaluation of a web structure.
12
Content available remote Filtracja nieustalona w wielowarstwowych strukturach włókninowych
PL
Celem pracy było zaprojektowanie wielowarstwowych wkładów filtracyjnych, poprawiających ekonomikę procesów separacji aerozoli. Przeprowadzono badania pracy struktur złożonych z trzech warstw pojedynczych o różnej budowie wewnętrznej, z których jedna to nanowarstwa, ułożonych w różnych konfiguracjach podczas oczyszczania gazu zawierającego cząstki stałe. Analiza zmian ich morfologii i zdeponowanych na nich cząstek na różnych etapach procesu filtracji posłużyła do wybrania optymalnej struktury.
EN
The aim of this study was to design a multilayer filter structure, improving the economics of aerosols' separation processes. Three individual various fibrous layers (one of them was a nanolayer) arranged in different configurations were investigated during purification of gas from solid particles. Analysis of changes in their morphology during various stages of the filtration process was used in the selection of optimal filter structure.
EN
Solution viscosity can be regarded as the most important factor in determining the morphology of the product obtained in electrospinning. Viscosity can be adjusted for a given solution by tuning the solution temperature or by adding fillers to the solution prepared. The electrospinning of PLA solution was performed at a temperature ranging from 25 to 100 °C to determine the effects of temperature on fiber morphology. For the solution of sufficiently high entanglement density (i.e., 20 wt%), the as-spun fiber diameter was in the range of 330 ± 20 nm because the electrospinning was conducted at elevated temperatures. In contrast, for the solution without sufficient entanglement density (i.e., 13 wt%), the solution entanglement density was enhanced by the addition of fillers, which caused the as-spun fibers to become smooth. The fiber diameter obtained was in the range of 90 ± 10 nm. By varying the solution temperature, the chain entanglement status existing in the solution remained intact. In contrast, the chain entanglement density could be enhanced by the addition of fillers. However, both temperature and fillers significantly altered the solution viscosity. Therefore a complete understanding of the temperature and filler effect on the solution and electrospinning gave rise to a feasible route for manipulating the as-spun fiber diameter.
PL
Lepkość roztworu można uznać za najważniejszy czynnik dla określenia morfologii produktu otrzymanego w procesie elektroprzędzenia. Lepkość może być dostosowana do danego roztworu przez regulację temperatury roztworu lub przez dodanie wypełniaczy do przygotowanego wcześniej roztworu. Elektroprzędzenie roztworu PLA prowadzono w zakresie temperatur od 25 do 100 °C w celu wyznaczenia wpływu temperatury na morfologię włókien. Przy roztworach o wysokim stopniu splatania łańcuchów polimeru (np., 20 wt%), dzięki prowadzeniu procesu przędzenia w wysokiej temperaturze udało się zredukować średnicę włókien do 330 ± 20 nm. Przy mniejszym stopniu splatania łańcuchów polimeru (np. 13 wt%) dodawano wypełniacze i uzyskiwano średnice włókien 90 ± 10 nm. Pełne zrozumienie wpływu temperatury i zastosowanych wypełniaczy na roztwór i proces elektroprzędzenia jest ważny dla otrzymywania określonej średnicy przędzonych włókien.
PL
W wyniku procesu elektroformowania (ang. electro-spinning, ES) otrzymywana jest włóknista forma polimeru. W wyniku modyfikacji polimerowego prekursora poprzez dodatek nanomodyfikatorów możliwe staje się uzyskanie włókien nanokompozytowych. Jednoczesne elektroformowanie (ang. concurrent electrospinning, co-ES), stanowiące modyfikację standardowej techniki ES, umożliwia wytworzenie nowej grupy materiałów, np. powłok zbudowanych z różnorodnych komponentów, włóknistych struktur przestrzennych na rusztowania komórkowe, materiałów gradientowych o różnym udziale składnika włóknistego, włóknistych zbrojeń w technologii nanokompozytów i wielu innych. Celem niniejszej pracy było opracowanie warunków formowania nanowłókien z PLA i GEL. Badania te stanowią pierwszy etap pracy, której celem jest opracowanie warunków jednoczesnego elektroformowania kompozytowej struktury PLA/GEL. W ramach omawianej pracy otrzymano oddzielnie włókna polimerowe z PLA lub żelatyny. W tym celu przeprowadzono proces elektroformowania z wykorzystaniem układu doświadczalnego zaprojektowanego i skonstruowanego w Katedrze Biomateriałów, AGH. Włókniste osady w formie maty były zbierane na uziemionym, obracającym się kolektorze pokrytym folią aluminiową. Otrzymane materiały były badane przy użyciu skaningowego mikroskopu elektronowego (ang. scanning electron microscope, SEM). Podczas badania uzyskanych włókien polimerowych wyznaczono ich średnice oraz analizowano ich morfologię. Średnice uzyskanych włókien z PLA zawierają się w przedziale 0,8-2,0 μm, natomiast włókien żelatynowych w przedziale 0,3-0,6μm. Uzyskane wartości charakteryzowały się niewielkim zróżnicowaniem i zależały od warunków eksperymentalnych procesu elektroformowania. Przedstawiono także wyniki badań otrzymywania włóknistej warstwowej kompozycji złożonej z nanowłókien. Podczas tego procesu na włókna polilaktydowe zebrane na folii aluminiowej nałożono warstwę włókien żelatynowych. Uzyskane struktury były badane przy użyciu skaningowego mikroskopu elektronowego.
EN
During the electrospinning (ES) process fibrous form of the polymer is obtained. Due to specific modification of a polymer precursor with nanoconstituents, nanocomposite fibres can also be produced. The concurrent electrospinning (co-ES) technique is a modification of the standard ES method in which multiple polymeric jets are being generated. This technique enables to develop new forms of structures - e.g., coatings, 3-D space architectures, gradient materials, fibrous reinforcements in nanocomposites. Our aim was to obtain the PLA and GEL nanofibres as the first stage of the experiments leading to concurrent electrospinning of the composite polylactide/ gelatine material. In this work individual polymeric fibres made of PLA or GEL were successfully produced. To do so the electrospinning setup designed and constructed in our Department was used. Fibrous deposits were collected on grounded rotating mandrel covered with aluminium foil. The obtained materials were analysed using scanning electron microscope (SEM). During the examination of the fibres acquired their diameters were measured. The general analysis of their morphologies was performed as well. Diameters of the PLA fibres obtained in this work ranged between 0.8 and 2.0 μm. GEL fibres were much smaller and had diameters ranging from 0.3 to 0.6 μm. All these values were narrowly distributed and depended on the experimental conditions. Composite polymeric material, get by layered deposition technique, was also obtained. During this process PLA fibres were firstly obtained on the aluminium foil and then covered with GEL fibres. The structure obtained was analysed in the same way as individual, nanocomposite polymeric fibres.
EN
The aim of the work was to obtain nano fibrous structures from biodegradable polymer with the addition of hydroxyapatite using electrospinning technique. Research was conducted with two types of solvent: dichloromethane and 50:50 mixture of dimethyl sulfoxide and dichloromethane. As a polymer a copolymer of L-lactide and glycolide (PLGA), commercial product with trade name Resomer®LG 824, was used. The preliminary electrospinning tests enabled to match optimal polymer solution concentration of tested samples. Rheological properties of all tested polymer solutions has been determined. Influence of electrospinning conditions and the type of solvent on macroscopic structure has been investigated.
EN
A single step electrospinning of chitosan and chitosan derivative-chitosan lactate nanofibres was studied in this paper. Chitosan was dissolved into acetic acid to produce structure-stable nanofibres. The effect of chitosan concentration and the content of acetic acid on the fibre diameter and morphology of nanofibres were studied in detail. The dynamic viscosity and surface tension of the electrospinning chitosan solutions were systematically studied as well. Based on the fundamental study on electrospinning chitosan in acetic acid, a chitosan derivative, chitosan lactate, was added to produce nanofibre in a pH-friendly aqueous environment. Chemical and morphological analyses demonstrated that chitosan lactate will positively influence the formation of nanofibres in higher pH condition although the morphology should be improved.
EN
In this work, preliminary investigations on the influence of the structure of nanofibre based composites on their strength properties were made. As a 'matrix' material, needle punched nonwoven from classical polypropylene fibres was used. Polyamide 6.6 nanofibres electrospun directly onto 'matrix' nonwoven were used as a reinforcement. In order to obtain composites, the nanofibre/'matrix' multilayer structures of different architecture but with the same weight percentage of nanofibres were pressed. On the basis of the investigations realised, it was found that collecting the nanofibres spun in the electrospinning process directly onto the 'matrix' nonwoven is more advantageous than transferring the layer of nanofibres from the collector onto the nonwoven. The tensile test indicates the influence of the composite structure on its strength properties. The composite obtained from the multilayer structure consisted of two thin layers of nanofibres uniformly arranged between the layers of 'matrix' nonwoven, characterized by a higher value of tensile stress and Young's modulus than a composite based on one thicker layer of nanofibres. From the results comes that the use of a higher number of nanofibre layers between the layers of 'matrix' nonwoven gives a more uniform arrangement of nanofibres in the composite space, favouring more the precise wetting of nanofibres by the matrix.
PL
Przedstawiono sposób formowania płaskich wyrobów włókienniczych zawierających warstwę nanowłókien oraz wstępną analizę wpływu struktury ułożenia warstw nanowłókien i włókniny "osnowowej" w pakiecie na właściwości wytrzymałościowe kompozytu termoplastycznego. Materiał osnowowy stanowiła włóknina igłowana ze standardowych włókien PP. Wzmocnienie stanowiły nanowłókna PA 6.6 wytwarzane w procesie elektroprzędzenia bezpośrednio na włókninę osnowową. Warstwy tworzyły pakiety zawierające procentowo taki sam udział wagowy nanowłókien, ale różnie rozmieszczone w przestrzeni pakietu. Na podstawie przeprowadzonych doświadczeń stwierdzono, że odbiór nanowłókien bezpośrednio na włókninę przeznaczoną na osnowę kompozytu jest znacznie korzystniejszy niż przenoszenie warstwy nanowłókien z kolektora na tę włókninę. W wyniku sprasowania pakietów w prasie hydraulicznej otrzymano gotowe kompozyty. Średnie wartości naprężenia maksymalnego i modułu Younga wyraźnie wykazują znaczny wpływ struktury kompozytu na jego właściwości wytrzymałościowe. Kompozyt ze struktury zawierającej dwie cieńsze warstwy nanowłókien równomiernie rozmieszczone pomiędzy warstwami włókniny, wykazuje większe naprężenie zrywające niż kompozyt na bazie jednej grubszej warstwy nanowłókien. Rezultat taki wskazuje, że użycie większej liczby warstw nanowłókien przedzielonych warstwami włókniny, daje bardziej równomierny rozkład nanowłókien w objętości kompozytu, a więc sprzyja dokładniejszemu ich zwilżaniu poprzez osnowę.
EN
The area of technical textile applications is very wide, with one of the most important being medical textiles. Polymer-iodine complexes (i.e. iodophors) are widely used in antiseptic products. Nanofibres with iodine may be used to disinfect skin in medicine, and iodine is also characterised by a fungicidal effect. The aim of this research was to form an electrospun PVA mat from nanofibres with iodine and establish the influence of iodine dissolved in ethanol on the structure of electrospun mats. The results showed that it is possible to form a PVA nonwoven mat with an iodine element inserted by the electrospinning process, which has an influence on the structure of the electrospun nonwoven mat.
PL
Związki kompleksowe polimer-jod (jodofory) są szeroko stosowane jako środki antyseptyczne. Nanowłókna z udziałem jodu mogą zostać użyte dla celów medycznych do dezynfekcji skóry, jod charakteryzuje się również efektem grzybobójczym. Celem badań było wytworzenie elektroprzędzionego runa PVA z nanowłókien z dodatkiem jodu i określenie wpływu rozpuszczonego w etanolu jodu na strukturę elektroprzędzionego runa. Wyniki wskazują, iż możliwe jest wytworzenie runa PVA metodą elektroprzędzenia nanowłókien z jodem, który jednak wpływa na strukturę runa.
EN
Polyacrylonitrile (PAN) nanofibres and carbon nanotube (CNT) reinforced PAN nanofibres were successfully electrospun. A polymer plasticiser, ethylene carbonate (EC), was added into the PAN/CNT solutions. The average diameter of the fibres varied between 80 and 240 nm. This study investigated the effects of polymer concentration, CNT and EC on the morphological characteristics of electrospun PAN fibres. Electrospinning parameters were set at constant values to prevent their mutual influences on the resultant morphology. It was observed that increasing the polymer concentration led to a reduction of beads density and an increase in the diameter of the PAN nanofibres. The fibre diameters also increased as a result of the addition of CNTs below the electrical percolation threshold. It was found that the inclusion of EC permits changes in the morphological characteristic of the PAN/CNT nanocomposite fibre regardless of the effects of its conductivity and viscosity.
EN
Nanostructured materials are considered as promising scaffolds for advanced tissue engineering. The reason is that the nanostructure of a material resembles the nanoarchitecture of the natural extracellular matrix (ECM), e.g., its organization into nanofibres, nanocrystals, nanosized folds of ECM molecules, etc. On nanostructured surfaces , the cell adhesion - mediating ECM molecules adsorb in an appropriate geometrical orientation which gives cell adhesion receptors access to specific sites in ECM molecules, such as amino acid sequences like Arg-Gly-Asp (RGD) , which serve as ligands for these receptors [1 - 3]. In addition, these materials enhance the adsorption of vitronectin, which is recognized preferentially by osteoblasts over other cell types [1 - 3]. Nanostructured materials have therefore been considered as suitable particularly for bone tissue engineering. Our studies have focused on carbon and hydroxy apatite nanoparticles as components of substrates for colonization with human bone - derived cells in vitro. Carbon nanoparticles, namely nanocrystalline diamond (NCD) and fullerenes C 60, have been used in the form of films deposited on carbon, glass, silicon and metallic substrates [3-4]. These films were o f continuous (NCD) or micropatterned (C 60 ) morphology , and have been intended for surface modifications of bone and dental implants [5], or for creating surfaces enabling regionally -selective cell adhesion and directed cell growth [6]. NCD films were also doped with boron, which resulted in improved adhesion, growth and osteogenic differentiation (measured by the production of collagen I, osteocalcin and alkaline phosphatase content) of human osteoblast-like M G 63 cells [7]. These beneficial effects can be explained by the increased electrical conductivity of boron-doped nanocrystalline diamond films, and can be further enhanced by active electric stimulation of cells. Some nanoparticles were also incorporated into polymeric matrices, e.g. foils of a terpolymer of polytetra fluoroethylene, poly vinyldi fluoride and poly- propylene ( carbon nanohorns, carbon nanotubes ) or nano fibres prepared by an electrospinning technique from polylactide, PLA (hydroxyapatite nanoparticles ) or poly( lactide-co-glycolide), PLGA (nanodiamond). All these composite substrates promoted the adhesion, growth and osteogenic differentiation of human osteoblast-like MG 63 cells in an extent similar to or even better than standard cell cultivation substrates , such as polystyrene dishes or microscopic glass coverslips. The adhesion and growth of MG 63 cells was particularly improved on the terpolymer of polytetrafluoroethylene, polyvinyldifluoride and polypropylene enriched with 4 wt. % of single-wall carbon nanohorns or multi-wall carbon nanotubes [3, 4]. The osteogenic differentiation of MG 63 cells (measured by concentration of osteocalcin) was enhanced on nanofibrous polylactide scaffolds loaded with 15 wt % of hydroxyapatite. On PLGA nanofibrous scaffolds loaded with approx. 23 wt. % of diamond particles, the number of initially adhering MG 63 cells on day 1 after seeding and the following growth dynamics of the cell swere similar to the values on pure PLGA scaffolds [8]. However, the cells on PLGA meshes reinforced with nanodiamond formed larger and more numerous talin-containing focal adhesion plaques. In addition, these plaques in cells on PLGA-nanodiamond scaffolds were localized not only at the cell periphery but also in the central part of the cells (FIG (1). Thus, it can be concluded that nanoparticle-modified materials are more promising than their non-modified counterparts f or colonization with bone cells, f or construction o f bone implants and f or bone t issue engineering.
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