Wyniki wyszukiwania - Biblioteka Nauki

1

Insights into the processing, structure, and mechanical performance of polyethylene/gypsum composites

100%

Hejna A. , Barczewski M. , Kosmela P. , Mysiukiewicz O.

Composites Theory and Practice

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2024

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tom R. 24, nr 1

7--24

EN

Polymer composites are used in all branches of industry, with numerous applications. Despite the many years of modifying commodity polymers, using novel fillers allows the range of their applicability to be extended. The impact of new types of fillers on the polymer matrix is not always predictable and requires further studies. The presented study analyzed the application of gypsum as a filler for composites based on high-density polyethylene (PE). The filler was introduced in the amounts of 1-20 wt.%, and its impact on the processing, static, and dynamic mechanical performance of the composites was investigated. At lower filler loadings, the composites could be processed without any hindrance of flowability compared to the neat PE. Up to 5 wt.%, the tensile strength was maintained at a similar level to PE due to the satisfactory quality of the interface and good interfacial adhesion. Higher loadings caused a drop in the tensile strength with a simultaneous rise in Young’s modulus. A further increase in the filler loading resulted in higher values of porosity and growth of the adhesion factor, determinedfrom the dynamic mechanical results, which led to deterioration of the mechanical performance.

2

Enhanced aging resistance of poly(ε-caprolactone)/brewers’ spent grain composites

88%

Hejna A. , Formela K. , Barczewski M. , Kuang T. , Saeb M. R.

Polimery

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2022

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tom Vol. 67, nr 1

3--12

PL

W prezentowanej pracy zbadano wpływ parametrów wytłaczania młóta browarnianego na odporność fotooksydacyjną kompozytów polimerowo-drzewnych na osnowie poli(ε-kaprolaktonu). Próbki napełniaczy o wyższej zawartości melanoidyn skuteczniej spowalniały degradację polimeru, hamując dekompozycję fazy amorficznej polimeru. W efekcie, obserwowano wyższe wartości współczynnika starzenia dla próbek zawierających młóto browarniane wytłaczane w wyższej temperaturze, co oznacza ograniczone zmniejszenie właściwości mechanicznych.

EN

The presented paper investigated the influence of the brewers’ spent grain (BSG) extrusion parameters on the photo-oxidative resistance of poly(ε-caprolactone)-based wood polymer composites. Filler samples characterized by the higher melanoidin content were more efficient in hindering of polymer degradation, inhibiting the decomposition of the polymer amorphous phase. As a result, deterioration of mechanical performance was limited, which was expressed by the higher values of aging factor for samples containing BSG extruded at higher temperatures.

3

The impact of filler thermomechanical modifications on static and dynamic mechanical performance of flexible foamed polyurethane/ground tire rubber/zinc borate composites

75%

Hejna A. , Kosmela P. , Olszewski A. , Formela K. , Zedler Ł. , Piasecki A. , Skórczewska K.

Composites Theory and Practice

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2023

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tom R. 23, nr 2

76--83

EN

The rapid development of the automotive industry is very beneficial to many aspects of human life, but it is also a very significant environmental burden. The most straightforward impact is related to the generation of exhaust, but the management of post-consumer car parts is also a major challenge. Among them, waste tires are very burdensome due to their enormous numbers. Therefore, it is essential to develop novel, environmentally friendly methods for their disposal, which would reduce their environmental impacts. One of the most promising approaches is shredding, resulting in the generation of ground tire rubber (GTR), which can be introduced into polymeric materials as a filler. The presented work is related to the thermomechanical treatment of GTR in a twin-screw extruder assisted by zinc borate (ZB), whose incorporation is aimed to increase interparticle friction within the extruder barrel. The impact of the treatment conditions on the particle size and Surface development of the GTR/ZB compositions was evaluated. Modified GTR was introduced into flexible polyurethane (PU) foams, and the impact on the static and dynamic mechanical performance of the resulting composites was investigated. Increasing the treatment temperature occurred to have an adverse effect on the tensile performance of the composites due to the agglomeration of GTR particles limiting the efficiency of stress transfer, which was also confirmed by dynamic mechanical analysis. On the other hand, increasing the ZB share in the GTR/ZB compositions limited PU disruptions related to the reactivity of the GTR functional groups with isocyanates, which enhanced the mechanical performance of the composites. It was proven that the proposed method of GTR thermomechanical treatment assisted by ZB might benefit the performance of flexible PU foamed composites, which could broaden the application range of GTR and provide novel ways for its efficient utilization.

4

Assessment of mechanical and thermomechanical properties of epoxy-basalt composites modified with halogen-free intumescent flame retardants

63%

Barczewski M. , Matykiewicz D. , Andrzejewski J. , Sałasińska K. , Paszkiewicz S. , Piasecki A. , Aniśko J. , Hejna A. , Przestacki D.

Composites Theory and Practice

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2023

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tom R. 23, nr 4

239--246

EN

This study aims to examine the effect of flame retardants (FRs) on the mechanical and thermomechanical properties of epoxy composites reinforced with basalt fibers. To effectively modify fire behavior, it is usually necessary to introduce significant amounts of FRs, which raises many concerns due to the potential deterioration of other functional properties, including mechanical performance. In this work, 30 wt.% halogen-free FRs, including a two-component FR (ammonium polyphosphate with pentaerythritol) and melamine cyanurate, were introduced into the polymer matrix. The unmodified and intumescent FR-modified epoxy resin composites reinforced with basalt fibers were subjected to static flexural test and thermomechanical properties assessment. The research results were correlated with the analysis of changes in the chemical composition assessed using Fourier transform infrared spectroscopy. As a result, the saturation of the reinforcing fabrics by the modified epoxy resin was limited, which caused a different failure mechanism under static bending and impact test conditions. Both FR systems reduced the flammability of the modified epoxy laminates along with also acceptable deterioration of the mechanical properties. The most beneficial effects considering the combination of all the analyzed features were noted for the two-component FR system containing ammonium polyphosphate and pentaerythritol.