The key feature of thermosensitive polymers is the reversible transition between the hydrophilic and hydrophopic forms depending on the temperature. Although the main research efforts are focused on their application in different kinds of drug delivery systems, this phenomenon also allows one to precisely control the stability of solid-liquid dispersions. In this paper research on the application of poly(N-isopropylacrylamide) copolymers in processing of minerals is presented. In the experiments tailings from flotation plant of one of the coal mines of Jastrzębska Spółka Węglowa S.A. (Poland) were used. A laser particle sizer Fritsch Analysette 22 was used in order to determine the Particle Size Distribution (PSD). It was proved that there are some substantial issues associated with the application of thermosensitive polymers in industrial practice which may exclude them from the common application. High salinity of suspension altered the value of Lower Critical Solution Temperature (LCST). Moreover, the co-polymers used in research proved to be efficient flocculating agents without any temperature rise. Finally, the dosage needed to achieve steric stabilization of suspension was greatly beyond economic justification.
Powdered polyaniline (PANI) was synthesised chemically with different doping anions namely hydrochloric acid, sulphuric acid and para-toluenesulfonic acid (pTSA). Two-step synthetic procedure was utilised at low temperature. The highest reaction efficiency was found for chlorine-doped PANI. Structural characterization with FTIR revealed the vibration bands characteristic to formation of the emeraldine salt. The surface morphology of doped PANIs was studied by SEM images which showed near globular shape and porous structures with different size of the aggregated particles. They were smaller for Cl–- or pTS–-doped PANI while for SO42– the size was markedly larger. The XRD patterns revealed that there are ordered regions especially for pTS– doped PANI, while the highest conductivity value was recorded for Cl– doped one followed by organic pTS– doped and SO42– doped one.
The general standards and guidelines recommendations for PCC suggest alternating conditions of curing: starting with wet conditions for effective hydration of Portland cement followed by air-dry conditions for polymer hardening. The often accepted curing regime of PCC covers 5 days of wet curing and then the air-dry curing but it is not the optimum one. The aim of the investigation was to find the best scenario for PCC with two types of polymer modifiers: two-component epoxy resin and water dispersion of polyacrylates. The following exploitation properties were accepted as the criteria of evaluation of PCC curing effectiveness: compressive strength, tensile splitting strength, surface tensile strength (by pull-off method), wear resistance, water penetration under pressure and resistance to carbonation. The optimum time of PCC wet curing is possibly between 7 and 14 days, however, it have to be verified experimentally for specific PCC composition.
The presented article is a report on progress in photovoltaic devices and material processing. A cadmium telluride solar cell as one of the most attractive option for thin-film polycrystalline cell constructions is presented. All typical manufacturing steps of this device, including recrystalisation and junction activation are explained. A new potential field of application for this kind of device - the BIPV (Building Integrated Photovoltaic) is named and discussed. All possible configuration options for this application, according to material properties and exploitation demands are considered. The experimental part of the presented paper is focused on practical implementation of the high- temperature polymer foil as the substrate of the newly designed device by the help of ICSVT (Isothermal Close Space Vapour Transport) technique. The evaluation of the polyester and polyamide foils according to the ICSVT/CSS manufacturing process parameters is described and discussed. A final conclusion on practical verification of these materials is also given.
We experimentally studied three different D-shape polymer optical fibres with an exposed core for their applications as surface plasmon resonance sensors. The first one was a conventional D-shape fibre with no microstructure while in two others the fibre core was surrounded by two rings of air holes. In one of the microstructured fibres we introduced special absorbing inclusions placed outside the microstructure to attenuate leaky modes. We compared the performance of the surface plasmon resonance sensors based on the three fibres. We showed that the fibre bending enhances the resonance in all investigated fibres. The measured sensitivity of about 610 nm/RIU for the refractive index of glycerol solution around 1.350 is similar in all fabricated sensors. However, the spectral width of the resonance curve is significantly lower for the fibre with inclusions suppressing the leaky modes.
We experimentally studied three different D-shape polymer optical fibres with an exposed core for their applications as surface plasmon resonance sensors. The first one was a conventional D-shape fibre with no microstructure while in two others the fibre core was surrounded by two rings of air holes. In one of the microstructured fibres we introduced special absorbing inclusions placed outside the microstructure to attenuate leaky modes. We compared the performance of the surface plasmon resonance sensors based on the three fibres. We showed that the fibre bending enhances the resonance in all investigated fibres. The measured sensitivity of about 610 nm/RIUfor the refractive index of glycerol solution around 1.350 is similar in all fabricated sensors. However, the spectral width of the resonance curve is significantly lower for the fibre with inclusions suppressing the leaky modes.
Several recent earthquakes have indicated that the design and construction of bridges based on former seismic design provisions are susceptible to fatal collapse triggered by the failure of reinforced concrete columns. This paper incorporates an experimental investigation into the seismic response of nonductile bridge piers strengthened with low-cost glass fiber reinforced polymers (LC-GFRP). Three full-scale bridge piers were tested under lateral cyclic loading. A control bridge pier was tested in the as-built condition and the other two bridge piers were experimentally tested after strengthening them with LC-GFRP jacketing. The LC-GFRP strengthening was performed using two different configurations. The control bridge pier showed poor seismic response with the progress of significant cracks at very low drift levels. Test results indicated the efficiency of the tested strengthening configurations to improve the performance of the strengthened bridge piers including crack pattern, yield, and ultimate cyclic load capacities, ductility ratio, dissipated energy capacity, initial stiffness degradation, and fracture mode.
The article presents the results of research concerning the effect of anthracite dust with 10%, 20%, 30%, 40% and 50% content in composites with a polypropylene matrix on selected properties. Hardness was examined with the Shore’s D method; stiffness, tensile strength as well as (MFR) Melt Flow Rate and (MVR) Melt Volume Rate of the investigated material were evaluated; wettability of the obtained material was also determined. Surface and volume resistivity were also investigated; the thermal properties of the filler were determined by thermogravimetric analysis (TGA). It was found that the investigated polypropylene composites filled with anthracite dust are hydrophobic materials and the composite hardness and stiffness are growing along with the volumetric increase of anthracite. It was noted that anthracite reinforces the material to a limited extent.
Asphalt mixtures are commonly used for the pavement construction for national roads with a high traffic load, as well as local roads with low traffic load. The constructions of local road pavement consisting of thinner, more flexible layers located on less stable subbase than the pavement of national roads, require reinforcement with asphalt layers characterized by increased fatigue life. Technologies that allow quick repairs and reinforcements, while improving the durability of the road pavement are being sought. Such technologies include the use of modifications of asphalt mixtures with special fibers. The paper presents the results of investigations of the properties of asphalt mixtures modified with innovative basalt-polymer fibers FRP. On the basis of the obtained test results according to the Marshall method, stiffness modulus and fatigue durability, the technical properties of asphalt mixtures with FRP fibers addition were improved. This technology significantly increases the fatigue life of asphalt concrete dedicated for repairs and reinforcements of road pavements.
Recently, new materials have been developed in the field of bridge design, one of which is FRP composite. To investigate this topic, the Polish National Centre for Research and Development has founded a research project, whose objectives are to develop, manufacture and test a typical FRP bridge superstructures. Two innovative ideas of FRP composite girder-deck structural systems for small and medium span bridges have been proposed. This paper describes the demonstrative bridges and presents the research results on their development and deployment. The finite element analysis and design procedure, structural evaluation in the laboratory and some results of the proof tests carried out on both bridge systems have been briefly presented.