The effect of water acrylate dispersion on the properties of polymer-carbon nanotube composites

The paper presents properties of polymer composites reinforced with carbon nanotubes (CNT) containing various mixtures of dispersion. Acrylates of different particle size and viscosity were used to produce composites. The mechanical strength of composites was determined by three-point bending tests. The roughness parameter of composites was determined with a profilometer and compared with the roughness parameter determined via atomic force microscopy (AFM). Also X-ray studies (phase composition analysis, crystallite sizes determination) were carried out on these composites. Measurements of the surface topography using the Tapping Mode method were performed, acquiring the data on the height and on the phase imaging. The change of intensity, crystallite size and half-value width of main reflections originating from carbon within the composites have been determined using the X-ray analysis. The density of each obtained composite was determined as well as the resistivity at room temperature. The density of composites is quite satisfactory and ranges from 0.27 to 0.35 g/cm3. Different composites vary not only in strength but also in density. Different properties were achieved by the use of various dispersions. Carbon nanotubes constituting the reinforcement for a polymer composite improve the mechanical properties and conductivity composite

Comparison of properties of polymer composite materials reinforced with carbon nanotubes

Carbon nanotubes because of their high mechanical, optical or electrical properties, have found use as semiconducting materials constituting the reinforcing phase in composite materials. The paper presents the results of the studies on the mechanical properties of polymer composites reinforced with carbon nanotubes (CNT). Three-point bending tests were carried out on the composites. The density of each obtained composite was determined as well as the surface roughness and the resistivity at room temperature. Moreover the surface studies on an atomic forces microscope (AFM) and X-ray studies (phase composition analysis, crystallite sizes determination) were carried out on such composites. Measurements of the surface topography using the Tapping Mode method were performed, acquiring the data on the height and on the phase imaging. The change of intensity, of crystallite size and of half-value width of main reflections originating from carbon for composites have been determined using the X-ray analysis. Carbon nanotubes constituting the reinforcement for a polymer composite improve the mechanical properties and conductivity of the composite

Charakterystyka nanorurek węglowych modyfikowanych kobaltem, miedzią i bromem

The paper presents results of studies on carbon nanotubes – as received, after cleaning and also after modification. Functional groups as well as metal nanoparticles have been attached, originating from cobalt sulphate, copper acetate and a mixture of hydrogen bromide and bromide. The surface studies on an atomic forces microscope (AFM), X-ray studies (phase composition analysis, crystallite sizes determination) as well as Raman spectroscopy studies were carried out on such nanotubes. The surface topography studies have shown that after the modification the diameter and length of nanotubes change. Also the surface development changes, which has been determined through roughness parameter measurements. The change of intensity, of crystallite size and of half-value width of main reflections originating from carbon for nanotubes modified in various ways have been determined using the X-ray analysis

Unique properties of silver and copper silica-based nanocomposites as antimicrobial agents

The paper reports a new route for the fabrication and determination of physicochemical properties and biological activity, of metallic silica-based nanostructure (Ag/SiO2, Cu/SiO2). A research studies shows mono-dispersed nanoparticles in silica matrix with an average size of 12 nm for silver, as well as 12 nm and 4 nm, respectively for copper in hydrophobic and hydrophilic silica composites. The chemical analysis highlights metallic silver and copper ions heterogeneously distributed in the composite as well as metallic oxides such as Ag2O, Cu2O and CuO in hydrophobic system, and CuO in hydrophilic one. Structural research evidences the presence of amorphous, stoichiometric and non-stoichiometric crystalline phase of silica. Biological studies reveal potentially inhibition of growth gram-positive and gram-negative bacteria as well as microscopic fungi. The size of metal nanoparticles and level of silica hydrophobicity show the highest inhibition bacterial growth for hydrophilic system with embedding inside them, 4 nm in size copper nanoparticles. Finally, cytotoxic interaction against human cells with respect to silver and copper silica-based nanocomposites was not found

Study of the cap structure of (3, 3),(4, 4) and (5, 5)-SWCNTs: Application of the sphere-in-contact model

We have applied the sphere-in-contact model supported by hybrid Density Functional Theory (DFT) calculations to elucidate the cap geometry of the sub-nanometer in dimension (3,3), (4,4) and (5,5) single-wall carbon-nanotubes (SWCNTs). Our approach predicts certain cap-geometries that do not comprise of the commonly known for their stability combination of pentagonal and hexagonal carbon rings but also tetragonal, trigonal and all-pentagonal structures. Based on hybrid-DFT calculations carbon atoms in these new cap geometries have similar stability to carbon found in other fullerene-like capped zig-zag and arm-chair nanotubes (i.e., (5,5), (6,6), (9,0) and (10,0)) that are known to be stable and synthetically accessible. We find that the cap structure of the (3,3)-CNTs is a pointy carbon geometry comprised of six pentagonal rings with a single carbon atom at the tip apex. In this tip geometry the carbon atom at the tip apex does not have the usual sp2 or sp3 geometry but an unusual trigonal pyramidal configuration. DFT calculations of the molecular orbitals and density-of-states of the tip show that this tip structure apart from being stable can be used in scanning probe microscopies such as STM for very high resolution imaging

Pogłębione oczyszczanie ścieków w nanofiltracji. Wpływ membrany i warunków prowadzenia procesu na jego efektywność

In recent years, increasing attention is focused on the presence of endocrine disrupting chemicals (EDCs) in the aquatic environment that degrade its quality. These substances and derivatives of their incomplete oxidation, even at low concentrations discharge with effluent streams into natural reservoirs, strongly degrade water quality and pose a serious threat to aquatic ecosystems. Among EDCs, which presence even in trace amount is adverse for biological equilibrium in aquatic environment to which belong inter alia xenoestrogens (ie bisphenol A). The aim of this study was to polish wastewater constituting effluent from municipal WWTP in the nanofiltration process. Two types of membranes were used, differ in molecular weight cut-off and material (cellulose acetate, polyethersulphone). The nanofiltration process was carried out in pressure installation enabling conduction of the process in the dead-end mode on membrane area of 0.44 m2. Polishing effectiveness was evaluated on the base of the reduction degree of typical pollution indicators (COD, TOC, phenolic compounds, total nitrogen) and bisphenol A. Obtained results show that removal efficiency of phenolic compounds in case of applied membranes was comparable. Overall it was found that membranes characterized of diversified hydraulic permeability and resistance to fouling, what constitute important factor during exploitation of membrane processes.Celem niniejszej pracy było pogłębione oczyszczenie ścieków rzeczywistych stanowiących odpływ z komunalnej oczyszczalni ścieków w procesie nanofiltracji. Zastosowane membrany nanofiltracyjne różniły się graniczną masą molową i materiałem, z jakiego je wykonano (octan celulozy i polieterosulfon). Proces filtracji membranowej odbywał się w ciśnieniowym urządzeniu przystosowanym do prowadzenia procesu w układzie filtracji jednokierunkowej (dead-end), na membranie o powierzchni czynnej 0,44 m2. Efektywność procesu doczyszczania została określona na podstawie stopnia obniżenia bisfenolu A i typowych wskaźników zanieczyszczeń (COD, TOC, IC (węgiel nieorganiczny), Nog.). Uzyskane wyniki wskazują, że stopień usuwania mikrozanieczyszczeń na badanych membranach był porównywalny. Badane membrany nanofiltracyjne charakteryzowały się zróżnicowaną wydajnością hydrauliczną i odpornością na foulingu, co jest istotne z punktu widzenia eksploatacji procesów

Antibacterial effect of silver nanoparticles synthesized on polyvinyl alcohol

Silver nanoparticles synthesized on PVA (compound 1) and on PVA/silica (compound 2) were tested for antibacterial effect on E. coli, P. aeruginosa and S. aureus strains. The bactericidal effects of silver nanoparticles were compared based on diameter of inhibition zones in discs diffusion method, Minimum Inhibitory Concentration (MIC) and Minimum Bactericidal Concentration (MBC) as well as medium supplemented with different concentration of nanoparticles. The results showed the strong antibacterial effect of silver nanoparticles against tested bacteria, the MIC values for silver on PVA (compound 1) were 3.1 µg·ml‒1 for E. coli and 6.25 for P. aeruginosa and S. aureus. For silver nanoparticles on the PVA/silica complex (compound 2), MIC values were 6.25 and MBC 12.5 µg·ml‒1 for all investigated strains. Both tested silver nanoparticles compounds caused complete inhibition of growth of E. coli, P. aeruginosa and S. aureus at concentration 5 µg·ml‒1 in medium

The Effect of Water Acrylate Dispersion on the Properties of Polymer-Carbon Nanotube Composites / Wpływ Wodnej Dyspersji Akrylanowej Na Właściwości Kompozytów Polimer-Nanorurki Węglowe

The paper presents properties of polymer composites reinforced with carbon nanotubes (CNT) containing various mixtures of dispersion. Acrylates of different particle size and viscosity were used to produce composites. The mechanical strength of composites was determined by three-point bending tests. The roughness parameter of composites was determined with a profilometer and compared with the roughness parameter determined via atomic force microscopy (AFM). Also X-ray studies (phase composition analysis, crystallite sizes determination) were carried out on these composites. Measurements of the surface topography using the Tapping Mode method were performed, acquiring the data on the height and on the phase imaging. The change of intensity, crystallite size and half-value width of main reflections originating from carbon within the composites have been determined using the X-ray analysis. The density of each obtained composite was determined as well as the resistivity at room temperature. The density of composites is quite satisfactory and ranges from 0.27 to 0.35 g/cm3. Different composites vary not only in strength but also in density. Different properties were achieved by the use of various dispersions. Carbon nanotubes constituting the reinforcement for a polymer composite improve the mechanical properties and conductivity composite