In this study, the influence of carbonate lake sediments (Polylactide/Carbonate Lake Sediments–PLA/CLS) on the mechanical and structural properties of polylactide matrix composites was investigated. Two fractions of sediments originating from 3–8 and 8–12 m were analysed for differences in particle size by distribution (Dynamic Light Scattering–DLS), phase composition (X-ray Diffraction–XRD), the presence of surface functional groups (Fourier Transform-Infrared–FT-IR), and thermal stability (Thermogravimetric Analysis–TGA). Microscopic observations of the composite fractures were also performed. The effect of the precipitate fraction on the mechanical properties of the composites before and after conditioning in the weathering chamber was verified through peel strength, flexural strength, and impact strength tests. A melt flow rate study was performed to evaluate the effect of sediment on the processing properties of the PLA/CLS composite. Hydrophobic-hydrophilic properties were also investigated, and fracture analysis was performed by optical and electron microscopy. The addition of carbon lake sediments to PLA allows for the obtention of composites resistant to environmental factors such as elevated temperature or humidity. Moreover, PLA/CLS composites show a higher flow rate and higher surface hydrophobicity in comparison with unmodified PLA.

This paper presents the impact of accelerated aging on selected mechanical and thermal properties of isotactic polypropylene (iPP) composites filled with sedimentary hybrid natural filler-Opoka rock. The filler was used in two forms: an industrial raw material originating as a subsieve fraction natural material, and a rock calcinated at 1000 °C for production of phosphorous sorbents. Fillers were incorporated with constant amount of 5 wt % of the resulting composite, and the material was subjected to accelerated weathering tests with different exposition times. The neat polypropylene and composites with calcium carbonate as a reference filler material were used for comparison. The aim of the research was to determine the possibility of using the Opoka rock as a new hybrid filler for polypropylene, which could be an alternative to the widely used calcium carbonate and silica. The thermal, mechanical, and structural properties were evaluated by means of differential scanning calorimetry (DSC), tensile tests, scanning electron microscopy (SEM), and Fourier-transform infrared spectroscopy with attenuated total reflectance (FTIR/ATR) prior to and after accelerated aging. As a result, it was found that the composites of polypropylene with Opoka were characterized by similar or higher functional properties and higher resistance to photodegradation compared to composites with conventional calcium carbonate. The results of measurements of mechanical properties, structural and surface changes, and the carbonyl index as a function of accelerated aging proved that Opoka was an effective ultraviolet (UV) stabilizer, significantly exceeding the reference calcium carbonate in this respect. The new hybrid filler of natural origin in the form of Opoka can therefore be used not only as a typical powder filler, but above all as a UV blocker/stabilizer, thus extending the life of polypropylene composites, especially for outdoor applications.

The purpose of the study was to determine whether lake sediments could be a potential raw material for the plastics industry. The examined samples were obtained in a complex process of sediment collection from Lake Swarzędzkie located in the region of Wielkopolska, Poland, followed by granulometric analysis by sieving and quartz grain shape analysis, with preparation of geotechnical sheets. The works involved the examination of physico-chemical characteristics of carbonate lake sediments and the analysis of impact of the sediments’ depth extraction on their chemical composition and physico-chemical properties. The lake sediment consists mainly of calcium carbonate (CaCO3) and can be a potential filler for plastics. Tests were carried out to determine chemical composition of the sediments and their thermal stability. The thermogravimetric analysis showed the three stages of the thermal decomposition. Sediments in deeper layers of the lake are characterised by the presence of not only CaCO3 and silica, but also other chemical compounds, including aluminosilicates. In addition, as the depth increases, the average size of sediment particles changes, with the main fraction particle size being the smallest for the material from the 6–12 m depth. Additionally, carbon content systematically decreases with increasing depth.

No abstract

This article concerns the use of remote sensing methods to assess the potential of tourism and recreation of lakes by using unmanned aerial vehicles as a tool that offers new measurement possibilities in such difficult areas to research as river and lake systems. For the purpose of the study, air surveys over three lakes used for tourism and recreation purposes were planned and carried out. These were the following lakes: Swarzędzkie, Wolsztyńskie and Zbąszyńskie located in western Poland. The photos were taken with a RGB and a multispectral cameras. On the basis of calculated orthophotomaps and digital surface models, anthropogenic and natural values were assessed. The examples of the research show the versatile possibilities of using drones dependent on the type sensor used. Remote sensing performed from the deck of an unmanned aircraft is widely used in the study of lakes and is an alternative to existing land and water research methods.