23 research outputs found
W艂贸kna PAN zawieraj膮ce wielo艣cienne nanorurki w臋glowe formowane metod膮 z roztworu na mokro
The spinning conditions of wet spun polyacrylonitrile (PAN) fibres containing multi-walled carbon nanotubes (MWCNTs) were investigated. On the basis of images from a transmission electron microscope, it was shown that the MWCNTs are well dispersed in the fibre matrix as well as straightened and oriented in the direction of the fibre axis. The presence of MWCNTs in the fibre matter caused an increase in the crystallinity of the precursor fibres and a decrease in their porosity. The tenacity of the composite fibres was lower than that of pure PAN fibres, which was caused by the fact that carbon nanotubes hindered deformation in the drawing stages, resulting in a lower draw ratio possible to be obtained of composite fibres compared to standard fibres. For the PAN precursor fibres obtained a two stage carbonisation process was conducted: The first stage was conducted in an oxidative atmosphere (at 140 掳C for 5 hours and then at 200 掳C for 6 hours in air). The second stage was conducted in an inert atmosphere (at 1000 掳C for 5 minutes in argon atmosphere). The strength of carbon fibres containing MWCNTs obtained shows, in the majority, no significant differences in comparision to reference fibres without MWCNTs. However, the tensile strength was lower.Zbadano wp艂yw warunk贸w formowania w艂贸kien poliakrylonitrylowych (PAN) zawieraj膮cych wielo艣cienne nanorurki w臋glowe (MWCNT) otrzymywanych metod膮 z roztworu na mokro. Na podstawie obraz贸w uzyskanych z mikroskopu transmisyjnego stwierdzono, i偶 nanorurki w臋glowe s膮 dobrze rozproszone w tworzywie w艂贸kien i zorientowane w kierunku osi w艂贸kna. Obecno艣膰 nanorurek w臋glowych w tworzywie w艂贸kien skutkowa艂a wzrostem stopnia krystaliczno艣ci w艂贸kien oraz obni偶eniem ich porowato艣ci. Wytrzyma艂o艣膰 w艂a艣ciwa w艂贸kien kompozytowych by艂a ni偶sza w por贸wnaniu do wytrzyma艂o艣ci w艂贸kien niezawieraj膮cych nanorurek w臋glowych. By艂o to spowodowane faktem, i偶 nanorurki w臋glowe utrudnia艂y procesy deformacyjne podczas rozci膮gu, co skutkowa艂o ni偶sz膮 warto艣ci膮 rozci膮gu ca艂kowitego uzyskiwanego dla w艂贸kien kompozytowych w por贸wnaniu do w艂贸kien bez nanorurek w臋glowych. Dla uzyskanych w艂贸kien w臋glowych przeprowadzono dwuetapowy proces karbonizacji: pierwszy etap w atmosferze utleniaj膮cej (w temp. 140 掳C w czasie 5 godzin, a nast臋pnie w 200 掳C w czasie 6 godzin, w atmosferze powietrza), drugi etap w atmosferze argonu (w temp. 1000 掳C w czasie 5 minut). Dzi臋ki zastosowaniu nanorurek w臋glowych niestety nie uzyskano spodziewanego istotnego polepszenia wytrzyma艂o艣ci w艂贸kien w臋glowych
Composites for Bone Surgery Based on Micro- and Nanocarbons
In this work capabilities of polymer composites modified with carbon materials for application in the bone surgery were compared. The composite materials were produced from synthetic polymer PTFE-PVDF-PP modified with a carbon phase such as: short carbon fibres, carbon nanotubes and carbon fabrics. Determination of mechanical properties of the composite materials indicated that the carbon phase improves strength and Young's modulus of the composite. Moreover, the mechanical parameters can be controlled by the form and amount of the carbon phase introduced into the polymer matrix. Both the fibres and the carbon nanotubes influenced wettability and surface energy of the composites. Also topography of the materials surface was altered, and its roughness was optimal for bone cells (profilometry). Osteoblasts contacted with the polymer-carbon composites showed increased viability comparing with the ones contacting with the pure polymer foil (viability, and cells proliferation: MTT method, concentration of bone protein: viniculine and 尾-actine). Results of the investigations indicated that the composite materials containing carbon phases are potential materials for repairing of bone tissue damages
Composites for Bone Surgery Based on Micro- and Nanocarbons
In this work capabilities of polymer composites modified with carbon materials for application in the bone surgery were compared. The composite materials were produced from synthetic polymer PTFE-PVDF-PP modified with a carbon phase such as: short carbon fibres, carbon nanotubes and carbon fabrics. Determination of mechanical properties of the composite materials indicated that the carbon phase improves strength and Young's modulus of the composite. Moreover, the mechanical parameters can be controlled by the form and amount of the carbon phase introduced into the polymer matrix. Both the fibres and the carbon nanotubes influenced wettability and surface energy of the composites. Also topography of the materials surface was altered, and its roughness was optimal for bone cells (profilometry). Osteoblasts contacted with the polymer-carbon composites showed increased viability comparing with the ones contacting with the pure polymer foil (viability, and cells proliferation: MTT method, concentration of bone protein: viniculine and 尾-actine). Results of the investigations indicated that the composite materials containing carbon phases are potential materials for repairing of bone tissue damages
Haemocompatibility and cytotoxic studies of non-metallic composite materials modified with magnetic nano and microparticles
Purpose: Preventing the formation of blood clots on the surface of biomaterials and investigation of the reasons of their formation are the leading topics of the research and development of biomaterials for implants placed into the bloodstream. Biocompatibility and stability of a material in body fluids and direct effect on blood cell counts components are related both to the structure and physico-chemical state of an implant surface. The aim of this study was to determine haemocompatibility and cytotoxicity of polysulfone-based samples containing nano and micro particles of magnetite (Fe3O4). Methods: The polysulfone-based samples modified with nanometric and micrometric magnetite particles were examined. Physicochemical properties of the composites were determined by testing their wettability and surface roughness. The action of haemolytic, activation of coagulation system and cytotoxicity of composites was evaluated. Results: Wettability and roughness of materials were correlated with nanoparticles and microparticles content. In the tests of plasma coagulation system shortening of activated partial thromboplastin time for polysulfone with nano magnetite and with micro magnetite particles was observed in comparison with pure polysulfone. Prothrombine time and thrombine time values as well as fibrinogen concentration were unchanged. Haemolysis values were normal. Morphology and viability of cells were normal. Conclusions: Composites made from polysulfone modified with nanoparticles and microparticles of magnetite cause neither haemolytic nor cytotoxic reaction. These composites evoke plasma endogenous system activation