PL
 |
EN
Preferencje help
Polish version English version Język
Widoczny [Schowaj] Abstrakt
Liczba wyników

Znaleziono wyników: 9

Liczba wyników na stronie
first rewind previous Strona / 1 next fast forward last
Wyniki wyszukiwania
Wyszukiwano:
w słowach kluczowych:  epoksyd
help Sortuj według:

help Ogranicz wyniki do:
first rewind previous Strona / 1 next fast forward last
1
Content available remote Assessment of mechanical and thermomechanical properties of epoxy-basalt composites modified with halogen-free intumescent flame retardants
Barczewski Mateusz, Matykiewicz Danuta, Andrzejewski Jacek, Sałasińska Kamila, Paszkiewicz Sandra, Piasecki Adam, Aniśko Joanna, Hejna Aleksander, Przestacki Damian
Composites Theory and Practice
|
2023
|
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.
2
Content available remote Effect of nano-kaolinite weight fraction on interfacial shear strength of fibre reinforced nanocomposite
Hasan Hisham Mohammed Ali, Hasan Bahaa Aldin Abass
Composites Theory and Practice
|
2022
|
R. 22, nr 1
16--20
EN
Many studies around the world focus on the use of organic and inorganic additions to polymer composites to enhance their mechanical properties. Investigations were conducted to study the mechanical properties of composites with nano-kaolinite weight fractions of 1, 3, 5, 7, and 12% incorporated into an epoxy matrix. Further investigations were carried out on the diffusion of the epoxy nano-kaolinite monomer into the interfibrillar space when polypropylene and Kevlar rope fibre were added. The Kevlar fibre/matrix and polypropylene fibre/matrix interfacial shear strength was evaluated by the single fibre drag-out method. The highest interfacial shear strength was observed at a 5 wt.% nano-kaolinite content. Energy-dispersive X-ray spectroscopy (EDX) and scanning electron microscopy (SEM), as well as characterisation by X-ray diffraction (XRD), were performed on all the epoxy/nano-kaolinite, Kevlar specimens.
3
Content available remote Experimental investigation of bond–slip behavior of between-anchored steel strips to concrete surface
Kopraman Yağmur, Özdemir Anil, Anil Özgür, Sakin Shaimaa, Armakan Furkan
Archives of Civil and Mechanical Engineering
|
2022
|
Vol. 22, no. 4
art. no. e198, 2022
EN
Reinforced concrete and masonry structures may need strengthening or retrofitting for many different reasons. It is known that strengthening/retrofitting details developed with steel elements are used and widely preferred in these studies. Realistic knowledge of the bond–slip material model between the existing concrete surface and the steel strip in the strengthening/retrofitting details developed using steel strips is extremely important to determine the designed strengthened structural bearing capacity and load–displacement behavior. In the literature review, no study was found in which the bond–slip material model between concrete surfaces and steel strips was investigated extensively. For this reason, an experimental study was planned. In the experimental program, using a special axial tensile test setup designed by the authors, 72 test specimens were tested under the effect of monotonically increased axial tensile force. Axial load displacement, shear stress–shear displacement, and strain distribution values along the steel strip of the test specimens were obtained. It was interpreted how the results were affected by the experimental variables. An innovative bond–slip material model was proposed using the experimental results between the non-anchored and anchored steel strips and the concrete surface. It is thought that the bond–slip model between the developed steel strips and the concrete surface will be useful in the realistic calculation of the bearing capacity and general load–displacement behaviors of the strengthening/retrofitting details designed using steel strips. It can be used in finite element models. It can be used in finite element models. The increase in concrete compressive strength from 10 to 25 MPa increased the axial load maximum bearing capacity values of the steel strips by an average of 44%. The maximum bearing capacity values of the steel strips bonded with a 2 mm thickness epoxy layer were calculated by, on average of 86% higher than the test specimens bonded with 6 mm thickness epoxy. The maximum axial bearing forces of the test specimens in which the axial tensile force was applied concentrically were obtained on an average of 27% greater than the test specimens tested by applying eccentric loading. The maximum bearing capacity values of the test specimens with two anchors on the steel strips adhered to the concrete surface were obtained on an average of 42% higher than the non-anchored test specimens in which only epoxy was used. The maximum bearing capacity values of the test specimens with 400 mm steel strip adhesion length exhibited an average of 108% higher maximum bearing capacity values than the test specimens with 100 mm steel strip bond length.
4
Content available remote Thermal gravimetric analysis of glass fiber reinforced composite for understanding the impact of copper oxide in relation to titanium oxide filler particles
Alam Shahinoor, Chowdhury Mohammad Asaduzzaman
Composites Theory and Practice
|
2021
|
R. 21, nr 1-2
12--21
EN
In this work, the composite samples required to investigate their thermal properties were fabricated employing the conventional hand lay-up technique, followed by a light compression molding process. A fixed weight of plain woven glass fiber and epoxy with four different types of fillers as calcium carbonate (CaCO3), aluminum oxide (Al2O3), magnesium oxide (MgO) and titanium oxide (TiO2) or copper oxide (CuO) of different weights (5, 10 and 15 g) were studied. According to thermal gravimetric analysis (TGA), it was observed that the melting point (Tm) and glass-transition temperature (Tg) are affected by the presence of CuO and TiO2, which indicate the degree of composite crystallinity established by the stronger interfacial interaction by the CuO than that of the TiO2 particles and the amorphous region of the chain. These studies were supported by examination of the surface morphology of the composites by means of scanning electron microscopy (SEM).
5
Content available remote Effect of silica fume and calcium carbonate whisker on interfacial behavior of near-surface-mounted FRP with magnesium phosphate cement
Zhang Liwen, Geng Tao, Liu Zhouqiang, Zhang Wenhua, Shang Qinghu
Archives of Civil and Mechanical Engineering
|
2020
|
Vol. 20, no. 1
14--29
EN
Magnesium phosphate cement (MPC) is a potential substitute of epoxy as an adhesive material due to its advantages in setting time, early strength, and good fire and corrosion resistance. In this study, silica fume (SF) and calcium carbonate whisker (CCW) were employed to improve bond capacity of MPC which were used instead of epoxy in near-surface-mounted (NSM) fiber-reinforced polymer (FRP) systems. A direct pull-out test (DPT) was carried out to investigate bond performances of FRP–concrete interface after incorporating SF and CCW. According to the mix proportion of the MPC, a total of twenty-seven specimens in nine sets were divided into four groups: one group without additive, one group with SF alone, one group with CCW alone, and the last group with SF and CCW combination. Results showed that SF or CCW alone could improve MPC bond capacity, but their excess application would reduce it. SF and CCW combination, however, did not improve bond capacity as effectively as SF or CCW alone. Moreover, the addition of CCW would improve MPC’s bond ductility, with or without the adding of SF, but with the increase in CCW concentration, this improvement effect would decrease. Meanwhile, SF alone lowered its bond ductility.
6
Content available Reakcje utleniania wybranych grup funkcyjnych z wykorzystaniem oxone® jako źródła tlenu cząsteczkowego
Zawadzki P., Czardybon W., Chrobok A.
Wiadomości Chemiczne
|
2016
|
[Z] 70, 5-6
289--297
EN
Oxidation reactions belong to the group of the most commonly used processes in both organic and inorganic chemistry. The main issues in such transformation are usually safe handling of the oxidants as well as waste generation. Peroxymonosulfuric acid is one of the strongest oxidants. It was described for the first time in 1898 by Heinrich Caro. Nowadays, the commercial sources of KHSO5 are low-cost industrial bulk chemicals, e.g., the triple salt Oxone® (2KHSO5· KHSO4·K2SO4). These products are stable oxidizing agents commonly used in fine chemicals synthesis, and are easy to handle, non-toxic as well as generate non-polluting by-products. Over the past several years the scope of its use has extended. One of the most important transformation that have been made possible with the use of Oxone® are epoxidation and ketone formation. Epoxides and ketones are important synthetic building blocks widely used in the chemical industry for the production of pharmaceutical products, flavours, fragrances, resins, adhesives and paints. The use of Oxone® was demonstrated in several combinations both in classical methods that involved metal catalysis as well as in novel approaches with the use of microwaves and ionic liquids. Over the past 20 years, ionic liquids, together with supercritical fluids and water, have become powerful alternatives to conventional organic solvents. Ionic liquids are salts having in the structure an organic cation and an inorganic or organic anion, with a melting point below 100°C. The advantage of using ionic liquids is a big variety of available structures. Combinations of both ionic liquids and Oxone® offer an interesting alternative to classical oxidation methods used in industry.
7
Content available Application of carbon nanotubes (CNT) to design of the strain sensor
Grabowski K., Uhl T., Zbyrad P.
Pomiary Automatyka Kontrola
|
2012
|
R. 58, nr 11
984-986
EN
The aim of this work was to develop a sensor which could be easily applied to the tested material and integrated with it. Therefore, this paper is focused on the development of the Carbon Nanotube - a polymer strain sensor - which should fulfill such requirements. The development of such a sensor is discussed and the test of its performance are presented. Multiwalled CNTs were mixed with polymer and applied to the materials with use of screen printing. The sensor was tested for different types of loads. Manufacturing technology and sensor test results are presented in this work.
PL
W pracy opisano prototyp czujnika zrealizowany przy użyciu nanorurek węglowych oraz epoksydu. Czujnik został naniesiony na badany materiał (kompozyt włókna szklanego) przy użyciu sitodruku. Struktura sensora (rozłożenie nanorurek w epoksydzie) została zbadana przy użyciu mikroskopu elektronowego. Wykazano, że przy stosunkowo dużych zawartościach procentowych (powyżej 7.5%) nanorurki węglowe tworzą zbite skupiska, przy czym mniejsze zawartości procentowe pozwalają na stosunkowo równomierne rozłożenie nanorurek węglowych w epoksydzie. Dodatkowo czujniki zostały poddane badaniom statycznym jak i dynamicznym. Przy badaniach statycznych miało to na celu zbadania odpowiedzi sensora (czy jest zachowana jego liniowość). Przy obciążeniach dynamicznych celem było sprawdzenie czy dochodzi do uszkodzenia struktury sensora przy stosunkowo dużej ilości cykli obciążeń. Zmiany rezystancji zostały porównane ze zmianami odkształceń badanego materiału (uzyskanymi z maszyny wytrzymałościowej). Otrzymano liniowe odpowiedzi czujników zarówno przy małej jak i dużej liczbie cykli obciążeń.
8
Kompozyty epoksydowe jako materiały elektroizolacyjne.
Halama A., Traczewski A., Jerzmański D., Stankiewicz J.
Prace Naukowe Instytutu Podstaw Elektrotechniki i Elektrotechnologii Politechniki Wrocławskiej. Konferencje
|
2006
|
Vol. 44, nr 18
324-326
PL
W pracy przedstawiono wyniki badań wpływu różnych układów epoksydowych i wzmocnień włókna bazaltowego jako wzmocnienia na właściwości kompozytów.
EN
This article describes the influence of different epoxy systems resin systems and glass fiber reinforcements on mechanical and electrical properties of composites. The influence of fiber reinforcement with basalt on properties of composites was also investigated.
9
Content available remote Przydatność iniekcji w naprawie rys
Chmielewska B., Koper W.
Materiały Budowlane
|
2006
|
nr 12
37-41
first rewind previous Strona / 1 next fast forward last
JavaScript jest wyłączony w Twojej przeglądarce internetowej. Włącz go, a następnie odśwież stronę, aby móc w pełni z niej korzystać.