Chemically Driven Printed Textile Sensors Based on Graphene and Carbon Nanotubes

The unique properties of graphene, such as the high elasticity, mechanical strength, thermal conductivity, very high electrical conductivity and transparency, make them it an interesting material for stretchable electronic applications. In the work presented herein, the authors used graphene and carbon nanotubes to introduce chemical sensing properties into textile materials by means of a screen printing method. Carbon nanotubes and graphene pellets were dispersed in water and used as a printing paste in the screen printing process. Three printing paste compositions were prepared—0%, 1% and 3% graphene pellet content with a constant 3% carbon nanotube mass content. Commercially available materials were used in this process. As a substrate, a twill woven cotton fabric was utilized. It has been found that the addition of graphene to printing paste that contains carbon nanotubes significantly enhances the electrical conductivity and sensing properties of the final product

Printed Textiles with Chemical Sensor Properties

In this study the authors proposed the introduction of chemical sensors directly on textile surfaces in the form of conductive transmission parts using the screen-printing technique. A liquid vapour-sensitive, printing surface made with the use of multi-walled carbon nanotubes was also evaluated. Carbon nanotubes show effective chemo-sensory properties because the chemical agent leads to changes in electrical conductivity. The research concerned the assessment of sensor efficiency for chemical incentives in the form of selected fluids and their vapours. The best sensory properties were observed for polar vapour at a level of relative resistance over 40%. In the case of vapours of non-polar fluids the sensory reaction of the printed fabrics is much weaker – at a level of relative resistance of about 25%. The printed textile backings subjected to the influence of a fluid show an immediate reaction, while in the case of fluid vapour the reaction occurs after a few seconds. Detection of the presence of dangerous chemical agents such as organic liquids and their vapour is possible by means of a structure composed of sensors

Technologies Involved in the Manufacture of Smart Nonwoven Fabrics

Many methods can be used to protect humans against hazardous chemicals in the environment such as personal protective equipment and protective clothing. However, what matters most is prevention and early detection of threats. Detecting the presence of hazardous chemicals such as organic liquids and the vapours they give off is possible using sensors. Effective chemosensory properties are revealed by conductive polymers and carbon particles, where the electrical resistance of chemicals changes. Still open to debate is finding the optimum means of applying chemical sensors that would provide high sensitivity, durability, reliability, and resistance but at the same time would not be expensive. The authors propose introducing chemical sensors in the form of nonwoven fabrics produced by the melt-blown method and by electrospinning. The analysis takes account of melt-blown nonwoven fabric ​​based on polylactide (PLA)-containing carbon nanotubes, nonwoven fabric made by electrospinning based on polyethylene oxide–containing carbon nanotubes and carbon nonwoven fabric from polyacrylonitrile submicron precursor fibres formed by electrospinning. Assessment of the effectiveness of the sensors to liquid vapours including methanol, acetone, benzene and toluene (concentration 200 ppm) has been carried out. The resulting nonwoven sensors are characterized by good electrical conductivity and altered electrical resistance as a result of the presence of vapours

Udział Politechniki Łódzkiej w programie IAEA

Autorzy artykułu są pracownikami : Izabella Krucińska - Instytut Materiałoznawstwa Tekstyliów i Kompozytów Polimerowych ; Wydział Technologii Materiałowych i Wzornictwa Tekstyliów ; Politechnika Łódzka Piotr Ulański - Międzyresortowy Instytut Techniki Radiacyjnej - Wydział Chemiczny Politechniki ŁódzkiejArtykuł zamieszczony jest w : Życie Uczelni : biuletyn informacyjny Politechniki Łódzkiej nr 152, lipiec 2020Po wybuchu pandemii COVID-19 problemem w skali międzynarodowej stały się braki w zaopatrzeniu personelu medycznego, a także ogółu społeczeństwa, w sprzęt ochronny, między innymi maski ochronne. Powstało pytanie, czy komercyjnie dostępne typowe maski (z natury jednorazowe) z włókniny polipropylenowej mogą być w razie potrzeby sterylizowane i używane wielokrotnie

New Method for Preparation of Biodegradable Medical Materials Characterised by Highly Developed Porous Structures

This study addresses the preparation of biodegradable and highly porous materials with the chemical purity required for medical materials. The solution method for producing porous structures with table salt was modified through the application of plasticisers in the technological process. In this paper the term medical materials includes dressing and implantable materials as well as scaffolds for tissue culture. A new method is proposed using polymers such as poly(D,L-lactide) and dibutyrylchitin to produce porous structures with enhanced absorption properties

Technologie bioresorbowalnych wyrobów medycznych – opracowane w wyniku realizacji projektu kluczowego „Biodegradowalne wyroby włókniste”

Pod koniec 2008 r. rozpoczęto realizację projektu kluczowego pt. „Biodegradowalne wyroby włókniste”, POIG 01.03.01–00– 007/08 o akronimie BIOGRATEX. Projekt jest współfinansowany z funduszy strukturalnych w ramach Programu Operacyjnego Innowacyjna Gospodarka. Celem głównym projektu jest opracowanie innowacyjnych rozwiązań technologicznych, niezbędnych dla poszerzenia oferty wyrobów włóknistych produkowanych z użyciem polimerów biodegradowalnych, w większości pozyskiwanych z surowców odnawialnych, kierowanych nie tylko do sektora włókienniczego, ale również dla rolnictwa i medycyny. Celem niniejszej publikacji jest przedstawienie opisu trzech technologii odnoszących się do wyrobów przeznaczonych do zastosowań w medycynie regeneracyjnej. Opisano technologię formowania włókien z roztworu polimeru będącego kopolimerem L-laktydu i glikolidu (PGLA), którego syntezę opracowano w ramach projektu. Kolejna technologia dotyczy materiałów nanowłóknistych wytwarzanych metodą elektroprzędzenia z roztworu polimeru PGLA oraz z roztworu mieszaniny polimerów PGLA i hydroksymaślanu (PHB). Oba roztwory polimeru w DMSO przędziono z dodatkiem hydroksyapatytu (HAp). Wytworzony materiał włóknisty zaprojektowano do stosowania przy regeneracji tkanki kostnej, jako materiał osteokonduktywny, osteoinduktywny i bioresorbowalny. Trzecia opisana technologia odnosi się do wytwarzania prototypów bioresorbowalnych protez naczyń krwionośnych z PGLA o średnicach poniżej 6 mm. Przedstawiono możliwość zastosowania techniki elektroprzędzenia ze stopu polimeru wraz z wprowadzeniem dodatkowego procesu stabilizacji termicznej do wytwarzania struktur 3D o małych średnicach

Shaping Ability of ProTaper Next, Hyflex CM, and V-Taper 2H Nickel-Titanium Files in Mandibular Molars: A Micro-computed Tomographic Study

Introduction: Although micro-computed tomography (MCT) evaluation of the shaping ability of ProTaper Next (PTN) and Hyflex CM (HCM) files has been reported, to our knowledge, no study has assessed the performance of V-Taper 2H (VT) files. The aim of this study was to evaluate and compare the shaping ability of PTN, HCM, and VT systems in the mesial canals of mandibular molars using MCT. Methods and Materials:  Thirty extracted first and second mandibular molars were scanned using MCT and randomly assigned to HCM, PTN, and VT groups. Images obtained before and after preparation were evaluated for the increase in the root canal volume, untouched surface area, and amount of accumulated hard tissue debris. One-way analysis of variance (ANOVA) and Kruskal-Wallis test were used to compare the variables in the groups (α=5%). Results: There were no statistically significant between-group differences in the postoperative measurements (P>0.05). The canal volume increased in all three groups: PTN   (73.84%), VT (73.48%), and HCM (49.29%). The largest and smallest untouched areas were observed in the PTN (41.37%) and VT (30.85%) groups, respectively (P>0.05). The debris formed during canal preparation was 1.84%, 2.16%, and 2.42% in the VT, PTN, and HCM groups, respectively (P>0.05). Conclusions: Based on our in vitro study, the PTN, HCM, and VT systems showed similar shaping abilities. None of the tested canals were completely free from debris, while the untouched surface area was considerably large. The VT system had the most favorable results with the smallest untouched surface area and least debris were. We would recommend further trials to endorse these findings

Development Trends in Electronics Printed: Intelligent Textiles Produced with the Use of Printing Techniques on Textile Substrates

The authors concentrated their attention on the new area of research, concerning properties of electrically conductive textiles, produced by printing techniques. Such materials can be used for monitoring, for example, the rhythm of breathing. The aim of this study was to develop a sensor of strains for the needs of wearable electronics. A resistance‐type sensor was made on a knitted fabric with shape memory, dedicated to monitor motor activity of human. The Weftloc knitted fabric shows elastic memory—thanks to the presence of elastomeric fibers. The dependence of sensoric properties of the Weftloc knitted fabric on the values of load, its increment rate, and its direction of action was tested. Mechanical parameters including total and elastic strain, elasticity degree, and strength were also assessed. The results indicate an anisotropic character of mechanical and sensoric behaviors of the sensor showing a particularly optimal behavior during diagonal loading. Electro‐conductive properties have been imparted to the Weftloc fabric by chemical deposition of polypyrrole dopped with Cl ions. In addition, authors used as a carrier functional water dispersion of carbon nanotubes AquaCyl that was adapted in the Department of Material and Commodity Sciences and Textile Metrology for forming electrically conductive pathways by film printing method. It was assumed that the electrically conductive paths are sensitive to chemical stimuli. Studies of the effectiveness of the sensors for chemical stimuli were conducted for selected pairs of liquids. The best sensory properties were obtained for the methanol vapor—the relative resistance (Rrel.) at the level above 40%. In the case of nonpolar liquid vapor, the sensoric sensitivity of the printed fabric was much lower, with Rrel. level below 29%. Properties of the electrically conductive materials, such as thermal conductivity, electrical conductivity, and resistance to chemicals, allow for widely using them nanotechnology

Wybrane zagadnienia z metrologii użytkowej odzieży funkcjonalnej

Politechnika Łódzka. Wydział Technologii Materiałowych i Wzornictwa Tekstyliów. Katedra Materiałoznawstwa, Towaroznawstwa i Metrologii Włókienniczej.Lodz University of Technology. Faculty of Material Technologies and Textile Design. Department of Material and Commodity Sciences and Textile Metrology.Rozwój technologii nowych materiałów, sposobu ich przetwarzania i wykorzystywania, a także coraz lepsze poznanie mechanizmów zachodzących w organizmie człowieka sprzyjają rozwojowi odzieży specjalnego przeznaczenia. Odzież już nie stanowi wyłącznie bariery przed zimnem, ale również ma za zadanie stanowić barierę przed czynnikami szkodliwymi, skrajnymi warunkami termicznymi, a także wspomagać funkcjonowanie organizmu jej użytkownika w warunkach ekstremalnych. Obecnie coraz większą uwagę zwraca się na zachowanie optymalnych warunków, w jakich powinien żyć i pracować człowiek, ponieważ zostało potwierdzone, że manualne i intelektualne zdolności człowieka osiągają swoje optimum w warunkach komfortu cieplnego. W tym kontekście problem odzieży ochronnej zapewniającej optymalny komfort cieplny użytkownika nabiera szczególnego znaczenia.Prace badawcze do prezentowanej książki były współfinansowane z Projektu pt. „Optymalizacja struktury ubioru ochronnego dla noworodków urodzonych przedwcześnie przy zastosowaniu oryginalnych narzędzi wspomagających proces projektowania” UMO-2011/03/B/ST8/06275, finansowanego przez Narodowe Centrum Nauki i Projektu pt. „Nowoczesne ochrony osobiste służb ratowniczych KSRG w oparciu o potrzeby użytkowników końcowych”, O ROB 0014 01/ID14/1, finansowanego przez Narodowe Centrum Badań i Rozwoju oraz z prac statutowych Wydziału Technologii Materiałowych i Wzornictwa Tekstyliów, Politechniki Łódzkiej