The Effect of the Aging Process on Selected Properties of Polypropylene Modified by Natural Fillers

The purpose of the research was to determine the aging-induced changes in the selected mechanical properties and flammability of polypropylene modified with natural fillers (sunflower husk, wheat bran, pine sawdust and talc). The fillers were introduced into polypropylene in a mechanical mixing process (weight content 20%). The samples were obtained with the use of an Allrounder 320 C500–170 laboratory injection molding machine. The aging process under artificial sample conditions was carried out in the laboratory chamber (aging time of 0, 60, 120, 240, 360 hours). The tests of the mechanical properties included the measurements of hardness, impact strength and tensile strength. The flammability tests were carried out with a vertical and horizontal alignment of the sample according to the PN-EN 60695–11–10 standard. As a result of the research, a significant impact of the introduction of natural fillers in the form of sunflower husks, wheat bran and pine sawdust on the selected properties of polypropylene was demonstrated. A large decrease in the impact toughness, a relatively small decrease in the short-term tensile strength as well as an increase in the elastic modulus and stress at rupture caused by the introduction of the natural fillers mentioned, were found. A beneficial effect was the relatively small impact of aging on the mechanical properties and flammability of the modified polypropylene fillers

Activating Methods and Techniques of Teaching/Llearning Vocational Subjects

Współczesna szkoła zawodowa zwraca uwagę na poprawę jakości nauczania. Zastosowanie aktywizujących metod i technik nauczania/uczenia się staje się odpowiedzią na potrzeby uczniów i uzupełnienie tradycyjnych metod pracy o inne podejścia pozwalające w ciekawszy i skuteczniejszy sposób przekazywać wiedzę oraz kształtować umiejętności zawodowe. Znajomość mnemotechnik i zasad sporządzania notatek w postaci map poznawczych umożliwi uczniom przenoszenie umiejętności trwałego przyswajania wiedzy na różne sytuacje, także pozaszkolne i pozazawodowe.Modern vocational school draws attention to improving the quality of teaching. The use of activating methods and techniques of teaching/learning becomes a response to the needs of students and complement traditional methods of work ing with other approaches, enabling a more interesting and more effective way to transfer knowledge and develop professional skills. Knowledge of the principles of mnemonics and notes in the form of cognitive maps allow students to transfer skills sustained learning in a variety of situations, including after-school and non-professional

Vocational education – expectations and needs

Zmniejszenie rozbieżności pomiędzy wymaganiami rynku pracy a ofertą szkolnictwa zawodowego wymaga ich diagnozowania i odpowiednich zmian w ofercie kształcenia, dokształcania i doskonalenia zawodowego. Istotne jest zwiększenie zakresu i pogłębienie współpracy między samorządem, urzędami pracy, poradnictwem zawodowym, szkołami zawodowymi, uczelniami technicznymi oraz pracodawcami. Powinny być przy tym uwzględniane potrzeby przedsiębiorców pod kątem kwalifikacji absolwentów oraz oczekiwania i potrzeby szkół.Reducing the differences between the requirements of the labor market, and offer vocational training needs of their diagnosis and appropriate changes in the offer of education, training and professional development. It is important to increase the scope and deepen the cooperation between the government, labor offices, vocational guidance, vocational schools, technical universities and employers. Should be taken into account the needs of employers in terms of qualifications of graduates and the expectations and needs of school

Time Management and the Dimensions of Teachers’ Professionalism

Dobre zarządzanie czasem jest szczególnie ważne w pracy szkoły. W artykule przedstawiono możliwości wykorzystania czasu w kontekście profesjonalizmu nauczycieli oraz badania nad subiektywną percepcją zarządzania czasem w powiązaniu z efektywnością działań i kompetencjami zawodowymi potrzebnymi w zmieniającej się rzeczywistości.Good time management is especially important at school work. The article presents the possibilities of using time in the context of teachers' professionalism and research on the subjective perception of time management in connection with the effectiveness of activities and professional competences needed in the changing reality

Perception of Time by Professional Teachers in the Word of New Technologies

Umiejętne zarządzanie swoim czasem nabiera szczególnego znaczenia we współczesnym świecie. W artykule przedstawiono możliwości wykorzystania nowoczesnych technologii przez nauczycieli w pracy zawodowej oraz badania nad subiektywną percepcją czasu.Skillful management of your time is of particular importance in the modern world. The article presents the possibilities of using modern technologies by teachers in professional work and research on subjective perception of time

Research on the Causes of Cracking of Pipes Derived from Recirculated Polyethylene

The objectives of the research was to determine the causes of cracks in pipes made of high-density polyethylene (HDPE) regranulate during their storage. A visual assessment of the cracks was carried out and their fatigue nature was found. Due to the insufficient information on the composition and properties of the processed regranulate, tests were carried out on the density distribution and mass flow rate of plastic samples taken from various areas of the pipe wall. Comparative tests were performed using infrared spectrophotometry of a plastic sample taken from a pipe, commercial HDPE and commercial polypropylene (PP) by attenuated total reflection/Fourier-transform infrared spectroscopy (ATR-FTIR), thermogravimetry (TG) and differencial scaning calorimetry (DSC) method. There were differences in density and flow rate depending on the distance from the outer surface of the pipe, reaching several percent. Based on the conducted spectroscopic, thermogravimetric and differential scanning calorimetry studies, none of the expected plastics contamination, mostly PP, has been found in recirculated polyethylene. Futhermore, the expected decrease in the temperature of phase transformations and the beginning of decomposition of polyethylene (PE) after recycling, compared to the original one, were visible. Possible causes of cracks were considered to be differences in the PE structure in the pipe wall and the occurrence of possible porous structures, which when storing pipes in variable load and temperature conditions could cause the propagation of microcracks

Study on the Properties and Structure of Rotationally Moulded Linear Low-Density Polyethylene Filled with Quartz Flour

The objective of this study is to determine selected properties of thin-walled rotationally moulded composite parts. Linear low-density polyethylene (LLDPE) filled with quartz flour (QF, 5–35 wt.%) was tested. High-density polyethylene functionalized with maleic anhydride (HDPE-g-MA) was used as a compatibility agent. Polymer samples were prepared with and without the compatibility agent (2 wt.% in relation to the QF content). The study investigated the effect of QF content and HDPE-g-MA on the properties of rotationally moulded parts, including their melt flow rate (MFR), thermal properties (DSC and TGA), thermomechanical properties (VST), mechanical and physical properties, microstructure, and geometry. Results showed that the properties of LLDPE/QF with HDPE-g-MA were significantly higher than those of LLDPE/QF without HDPE-g-MA. It was also found that the compatibility agent improved the composite material’s thermal stability. This improvement was attributed to interactions occurring between the composite material components due to the use of the compatibility agent. In addition to that, microscopic examination demonstrated that the use of HDPE-g-MA improved miscibility of the composite material components. The composite samples containing HDPE-g-MA had better surface geometry

Flammability of Polymer Compositions Filled with Wheat Bran

The article presents the results of flammability tests on polymer compositions with wheat bran (WB) as the applied filler, and polyethylene (PE) or poly(butylene succinate) (PBS) as the matrix material. Tests were conducted using samples of compositions containing 10, 30 and 50%wt wheat bran. The test samples were manufactured by injection moulding from compositions previously produced by extrusion pelleting. For comparative purposes, samples made only of the plastics used for the composition matrix were also examined. Flammability tests were carried out in accordance with the recommendations of EN 60695-11-10 Part 11–10 with horizontal and vertical positioning of the sample, using a universal flammability-test-stand. During the flammability tests, changes in the temperature field in the area of the burning sample were also recorded, using a thermal imaging camera. Sample residues after flammability tests were also examined with infrared spectroscopy (FTIR) to assess their thermal destruction. The results of the study showed a significant increase in flammability with bran content for both PE and PBS matrix compositions. Clear differences were also found in the combustion behaviour of the matrix materials alone. Both the burning rate and maximum flame temperature were lower in favour of PBS. PBS compositions with wheat bran also showed lower flammability, compared with their PE matrix counterparts

Aniline polymerization in a constant magnetic field environment

Badano wpływ stałego pola magnetycznego (SPM) na proces polimeryzacji polianiliny. Proces prowadzono na platynowych elektrodach płytkowych, nieizolowanych i izolowanych jednostronnie (z dwóch różnych stron teflonem), o powierzchniach skierowanych równolegle do linii sił SPM. Stwierdzono, że właściwości magnetyczne cząstek biorących udział w procesie polimeryzacji elektrochemicznej oraz ich ładunek (+/–) mają istotny wpływ na oddziaływanie SPM na przebieg procesu. Zaproponowano mechanizm wpływu SPM na zachodzące reakcje elektrochemiczne, oparty na powstawaniu efektu magnetohydrodynamicznego (MHD), powodującego zmianę szybkości transportu reagujących substancji w kierunku elektrody.The influence of the constant magnetic field (CMF) on the polymerization of polyaniline was investigated. The process was carried out on platinum plate electrodes, non-insulated and one-sided Teflon insulated (from two different sides), with surfaces directed parallel to the CMF line of force. It was found that the magnetic properties of the particles involved in the electrochemical polymerization process and their charge (+/-) have a significant impact on the influence of the CMF on the course of the process. The mechanism of the influence of CMF on the studied electrochemical reactions was proposed, based on the formation of the magnetohydrodynamic effect (MHD), causing a change in the rate of transport of the reacting substances towards the electrode