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1

Analysis of Strenght Properties of Carbon Fibre-Reinforced Composites

Bondyra Agnieszka, Łusiak Tomasz

Transactions on Aerospace Research

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2023

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Nr 1 (270)

45--66

EN

Tensile tests were carried out on three series of composite samples according to the ASTM (American Society for Testing and Materials). The materials tested were characterised by using the same manufacturing method. The specimens were hand-laminated using MGS L285/H285 epoxy resin. The feature that differentiates the structure of each laminate series is the type of reinforcement. A biaxial fabric IMS65 CTLX with a 0/90 arrangement was used to reinforce the C-series composite specimens; for the D-series, a symmetrical fabric Interglass 02037 with a 0/90 weave was used, and for the e-series specimens, a modular fabric IMS65 with a 45 weave was used. The share of composites in the manufacture of construction products is steadily increasing. This is due to the development of new technologies for manufacturing composite elements and composites, with properties that are more and more in line with the requirements of the industry resulting from technological progress. Composite products have to meet many performance requirements. Tensile testing is used to determine some of the key mechanical properties of laminates. Fibre-reinforced polymer (FRP) composites have been used in various engineering structures for many decades. Their unique physical and mechanical properties make them a well-known, most produced and most widely used type of composite materials. In the case of fibre composites, it is the fibres that take over the basic stresses and are responsible for achieving the appropriate stiffness and strength, while the matrix ensures optimum use of the properties of the fibres and gives shape to the manufactured element. The mechanical properties of the composite and its failure process are fundamentally dependent on the high strength of the fibres, the stiffness of the matrix and the strength of the fibre-matrix interface.

2

Rheological properties of polypropylene composites with calcium carbonate under high shear rates

Kloziński Arkadiusz, Lewandowski Krzysztof, Mirowski Jacek, Barczewski Mateusz, Jakubowska Paulina

Polimery

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2023

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Vol. 68, nr 7-8

403--412

EN

The rheological properties of isotactic polypropylene (iPP) and its composites with unmodified and stearic acid-modified calcium carbonate (5, 10, 20, 30 wt%) were investigated. The processability factor K of the composites was determined based on changes in the mass flow rate (MFR). The assessment of rheological properties was carried out at high shear rates, in the injection process, using a special in-line measuring head. Measurements were performed at a temperature of 230°C, in the range of apparent shear rate from 19,100 to 101,900 s-1, based on the Ostwald-de Waele power-law model. Comparative analysis of the processing and rheological characteristics, as determined with two techniques (off-line measurements and in-line measurements), has shown a diverse behaviour of polymer composites in flows (flow resistances, the behaviour of the flow and viscosity curves, the power law index), resulting from a varying fill degree, applied filler type and measuring shear rate range.

PL

Zbadano właściwości reologiczne izotaktycznego polipropylenu (iPP) oraz jego kompozytów z niemodyfikowanym i modyfikowanym kwasem stearynowym węglanem wapnia (5, 10, 20, 30% mas.). Współczynnik przetwarzalności K kompozytów określano na podstawie zmian masowego wskaźnika szybkości płynięcia (MFR). Ocenę właściwości reologicznych przeprowadzono w warunkach dużych szybkości ścinania, w procesie wtryskiwania, przy zastosowaniu specjalnej głowicy pomiarowej typu in-line. Pomiary wykonano w temperaturze 230°C, w zakresie pozornej szybkości ścinania od 19 100 do 101 900 s-1, w oparciu o model potęgowy Ostwalda-de Waele’a. Analiza porównawcza charakterystyk przetwórczych i reologicznych, wyznaczonych dwoma technikami pomiarowymi (off-line i in-line), wykazała zróżnicowany sposób zachowania się kompozytów polimerowych w przepływach (opory przepływu, przebiegi krzywych płynięcia i lepkości, wykładnik płynięcia), wynikający z różnego stopnia napełnienia, rodzaju zastosowanego napełniacza oraz zakresu pomiarowego szybkości ścinania.

3

Wybrane zastosowania kompozytów w wojsku

Błachnio Józef, Chalimoniuk Marek, Nidzgorska Adrianna

Journal of KONBiN

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2023

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Vol. 53, iss. 4

191--209

PL

W artykule przedstawiono problematykę dotyczącą zastosowania nowych rozwiązań konstrukcyjnych z wykorzystaniem materiałów kompozytowych, na szeroko rozumiane potrzeby wojska. Pokrótce przedstawiono charakterystykę kompozytów i ich właściwości, wyszczególniając ich liczne zalety, a także niedostatki. Omówiono nowe konstrukcje podzespołów samolotów, śmigłowców oraz zasygnalizowano wzrost udziału kompozytów polimerowych w lotnictwie wojskowym i cywilnym. Przedstawiono zastosowanie kompozytów do ochrony żołnierza: elastyczną kamizelkę kompozytową i hełm, do ochrony przed promieniowaniem mikrofalowym, jak również egzoszkielet żołnierza ułatwiający operacje na polu działań. Podkreślono możliwości szerokiego zastosowania materiałów kompozytowych w różnych gałęziach przemysłu.

EN

The article presents the issue of applying new design solutions from composite materials for military needs. The article also includes composites’ characteristics and properties, underlining their benefits and deficiencies. New aircraft and helicopter subassembly designs were demonstrated, and an increased use of polymer composites in civil and military aviation was mentioned. In addition, the application of composites used for the soldier’s protection in the form of elastic composite west, helmet against microwave radiation was depicted, as well as the soldier’s exoskeleton to facilitate operations on the field. Composites are future-oriented materials applied in civil and military areas due to their properties.

4

Comparative Evaluation of the Selected Mechanical Properties of Polymer Composites Reinforced with Glass and Hemp Fabrics

Scheibe Mieczysław, Bryll Katarzyna, Brożek Piotr, Czarnecka-Komorowska Dorota, Sosnowski Mariusz, Grabian Janusz, Garbacz Tomasz

Advances in Science and Technology. Research Journal

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2023

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Vol. 17, no 2

268--278

EN

The requirements of sustainable development of the economy force the replacement of the previously used composite materials in the production of elements not only with lighter, but also more durable materials. These materials should meet more and more stringent environmental protection requirements. This study aimed to determine the possibility of introducing a polymer structural composite reinforced with natural fiber into the structure of the hull of vessels instead of the commonly used polymer-glass composite (GFRP). The hemp fabric was used to reinforce the polymer matrix. The compared analysis of the physical properties of the classic GFRP composites with obtained new HFRP composites, i.e. density, impact strength, as well as resistance to static tensile and bending, was carried out. As a result of the performed analyzes and comparison of the results with the standards, it can be concluded that it is possible to apply a polymer-hemp (HFRP) composite for the shipbuilding and boatbuilding needs – limited to plating elements with medium and low strength requirements.

5

Analysis of the Surface Layer and Feed Force after Milling Polymer Composites with Coated and Uncoated Tools

Ciecieląg Krzysztof

Advances in Science and Technology. Research Journal

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2023

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Vol. 17, no 4

70--78

EN

Polymer composites are widely used in various fields and industries. This study investigated milling of four different glass and carbon fiber reinforced plastics. First, feed force values were determined in the milling process conducted using tools with polycrystalline diamond inserts, with titanium nitride-coated cemented carbide inserts and with uncoated ground cemented carbide inserts. Machined surfaces were then examined for roughness. Using scanning microscopy (SEM), differences in the surface layer were also determined. Results showed that the lowest force values were obtained in milling of glass fiber reinforced plastics using tools with polycrystalline diamond inserts. The best machining results in terms of roughness were obtained after milling glass fiber reinforced plastics.

6

The influence of calcium carbonate and its modifications on the extrusion process and selected properties of polypropylene cast films

Kloziński Arkadiusz, Szczepańska Małgorzata, Jakubowska Paulina, Samujło Bronisław, Barczewski Mateusz, Lota Grzegorz

Polimery

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2022

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Vol. 67, nr 10

509--521

EN

The effect of unmodified and stearic acid-modified calcium carbonate (5, 10, 20 and 30 wt%) on selected properties (tensile strength, puncture resistance, haze and gloss) and processability of polypropylene films (MVR, extensional viscosity) was investigated. The composites were obtained in the twin-screw extrusion process with cold granulation, and the films in the single-screw extrusion process, using a flat die head (so-called cast films) and a chill roll type cooling and pull-back device. It has been shown that stearic acid is an effective modifier of polypropylene processing properties both under shear and tensile flow conditions (lower extensional viscosity of films containing modified calcium carbonate).

PL

Zbadano wpływ dodatku 5, 10, 20 oraz 30 % mas. niemodyfikowanego imodyfikowanego kwasem stearynowym węglanu wapnia na wybrane właściwości użytkowe (wytrzymałość na rozciąganie, odporność na przebicie, zamglenie, połysk) iprzetwórcze folii polipropylenowych (MVR, lepkość wzdłużna). Kompozyty otrzymano w procesie dwuślimakowego wytłaczania z granulacją na zimno, a folie w procesie jednoślimakowego wytłaczania, przy użyciu głowicy płaskiej (tzw. cast films) oraz urządzenia chłodząco - odciągającego typu chill roll. Wykazano, że kwas stearynowy jest efektywnym modyfikatorem właściwości przetwórczych folii polipropylenowych zarówno w warunkach przepływu ścinającego, jak i rozciągającego (mniejsza lepkość wzdłużna folii zawierających modyfikowany węglan wapnia).

7

Polimerowe kompozyty w ochronie przed promieniowaniem mikrofalowym

Głuszewski Wojciech, Kubacki Roman

Nowa Energia

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2022

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nr 4

80--84

PL

Urządzenia i podzespoły elektroniczne, w których znajdują się układy scalone mogą ulec bezpowrotnemu zniszczeniu pod wpływem wysokomocowych impulsów elektromagnetycznych - HPM. Generatory HPM są stosowane do działań wojskowych, terrorystycznych oraz przestępczych. Skutki przerwania pracy, uszkodzenia lub zniszczenia systemów elektrycznych, bądź elektronicznych są szczególnie niebezpieczne dla: transportu drogowego, kolejowego i lotniczego oraz energetyki i telekomunikacji. W artykule omówiono wybrane wyniki badań nad radiacyjną modyfikacją kompozytów polimerowych typu: elastomer Engage 8200, szkło metaliczne, grafit - skutecznych w ochronie przed działaniem promieniowań mikrofalowych i radiowych. Celem prac było znalezienie nowego materiału absorpcyjnego o następujących parametrach: mniejszej lub znacznie mniejszej wadze w porównaniu z typowymi ferrytami, elastyczności i możliwości rozwijania na powierzchni ziemi, wytrzymałości mechanicznej na naciski, np. przejazd pojazdem mechanicznym.

8

The effect of kenaf loading on kenaf/ABS composites structure and thermal properties

Mashelmie S., Rabiatul Manisah M., Bahiyah Baba N., Mohd A.

Journal of Achievements in Materials and Manufacturing Engineering

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2022

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Vol. 111, nr 2

49--56

EN

Purpose: Many manufacturers have recently become interested in using fiber-reinforced polymer composites (FRPs) in structural applications. Synthetic fibres, such as carbon and glass fibres, have been commercialised internationally for decades, but they cause environmental issues because synthetic fibres are non-biodegradable and difficult to recycle once they have served their purpose, potentially polluting the environment. Thus, natural fibre composites like kenaf is a possible replacement for synthetic fibre due to their superior physical and mechanical properties. Kenaf appears to be the best candidate for replacing synthetic fibres in order to accomplish the goal of environmental preservation while also displaying excellent properties such as equivalent specific strength, low density, and renewable resources. Design/methodology/approach: The kenaf fiber was treated in KOH and added to ABS matrix to produce new composites at different loading (10, 15, 20 and 25 wt.%) by using Two Roll Mill machine. The influence of the fiber on the composites properties was evaluated. The produced material was subjected to SEM, MFI, TGA and DSC analysis. Findings: The incorporation of the treated kenaf fiber has an influence on the properties of kenaf/ABS composites. The addition of 10 wt.% kenaf was found to be the best loading with MFI value, initial degradation temperature and glass transition temperature at 0.8208 g/10 min, 322.63°C and 130°C respectively. The fiber was well dispersed in the matrix and shown good adhesion to the ABS. The addition of treated fiber contribute to a reduction in the MFI, improved the thermal stability of the composites and typical effects of Tg of the composite compare to pure ABS. Research limitations/implications: The results suggest the need to continue the study in order to further analyse higher kenaf loading and shed more light on the properties of the composites to improve understanding of kenaf/ABS composites. Originality/value: Obtained results are a solution to alternative of synthetic fibers, which may contribute to the sustainable development of composites materials industry through the utilization of kenaf fiber with ABS matrix.

9

Kompozyty na osnowie polilaktydu wzmacniane włóknem bazaltowym z dodatkiem antybakteryjnych nanocząstek do zastosowań biomedycznych

Rusin-Żurek Karina, Kuciel Stanisław

Inżynieria Materiałowa

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2022

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Vol. 43, nr 3

26--31

PL

W pracy oceniono wpływ dodatku włókien bazaltowych oraz antybakteryjnych nanocząstek metali, nanotlenku miedzi (CuO) i nanotlenku cynku (ZnO) na właściwości wytrzymałościowe, a także wpływ degradacji hydrolitycznej na spadek właściwości wytrzymałościowych kompozytów wytworzonych metodą wtryskiwania na osnowie polilaktydu. W celu przeprowadzenia badań wytworzono 9 kompozycji z zawartością 5 i 15% mas. włókien bazaltowych oraz 2-proc. dodatkiem nanocząstek metali. Dodatkowo każdy z kompozytów posiadał 2% dodatku kompatybilizatora - promotora mieszalności. W celu oceny właściwości wytrzymałościowych kompozyty zostały poddane próbom rozciągania, zginania oraz udarności. Przeprowadzono także degradację hydrolityczną w roztworze soli fizjologicznej w temp. 40°C. Wykonano również mikrofotografie SEM na przełomach po rozciąganiu w celu oceny efektów wzmocnienia oraz stopnia homogenizacji. Wyniki badań wykazały, że dodatek włókien bazaltowych zwiększył wytrzymałość na rozciąganie i zginanie, a także zwiększył sztywność kompozycji. W warunkach degradacji hydrolitycznej po 7 tygodniach nastąpił znaczący 30-50-proc. spadek wytrzymałości i sztywności materiałów. Dodatek antybakteryjnych nanocząstek tlenków metali zmniejszył właściwości wytrzymałościowe. Na zdjęciach z mikroskopii elektronowej po rozciąganiu kompozytów z dodatkiem nanocząstek tlenku cynku zaobserwowano przełomy kruche z obszarami silnie rozwiniętymi. Na zdjęciach SEM kompozytów z dodatkiem nanotlenku miedzi wyraźniej obserwowane były powierzchnie ugrupowań krystalicznych z włóknami bazaltowymi w osnowie. Wytworzone kompozyty z włóknem bazaltowym i antybakteryjnymi nanocząstkami metali mogą poprawić właściwości użytkowe wtryskiwanych elementów do zastosowań biomedycznych.

EN

The study assessed the effect of the addition of basalt fibers and antibacterial metal nanoparticles, copper nanoxide (CuO) and zinc nanoxide (ZnO), on the strength properties and influence of hydrolytic degradation on the decrease strength properties of composites produced by injection molding based on a polylactide (PLA). In order to carry out the research, 9 compositions were prepared with the 5 and 15% by mass basalt fibers (BF) content and 2% addition of metal nanoparticles. Additionally, each of the composites had a 2% addition of a compatibilizer - a miscibility promoter. In order to assess the strength properties, the composites were subjected to a tensile, bending and impact tests. Hydrolytic degradation was performered in physiological saline solution at 40°C. SEM micrographs of samples breakthroughs were taken to assess the effects of enhancement and the homogenization. The test results showed that the addition of BF increased the tensile and bending strength, and also increased the stiffness of the composition. After 7 weeks of hydrolytic degradation there was a significant 30-50% decrease in the strength and stiffness of the materials. The addition of antimicrobial metal oxide nanoparticles decreases the strength properties. In the SEM photos after tensile tests the composites with the addition of ZnO nanoparticles, it could be observed cleavage fractures with areas of strong developed. The SEM photos of composites with the addition of CuO show more clearly the surfaces crystalline groups with BF in the matrix. The produced composites with BF and antibacterial metal nanoparticles can improve the functional properties of the injected elements for biomedical applications.

10

Effect of calcinated halloysite on structure and properties of rigid poly(vinyl chloride) composites

Wieczorek Martina, Tomaszewska Jolanta, Bajda Tomasz, Długosz Jacek

Chemical and Process Engineering

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2022

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Vol. 43, nr 3

383-–404

EN

Halloysite is a filler which may be used to produce composites with thermoplastic polymer matrix. This work summarized the results of investigations of processing, structural, mechanical, and thermal properties of the composites with poly(vinyl chloride) (PVC) matrix and raw halloysite (HA) as well as its calcined product (KHA). The effectiveness of calcination was confirmed with X-ray diffraction, Fourier-transform infrared spectroscopy, scanning electron microscopy, and nitrogen adsorption method. The PVC composites with HA as well as KHA were processed in the molten state in the Brabender mixer chamber. The reduction of gelation time and simultaneous increase in maximum torque with filler content were found based on the results of plastographometric analysis. SEM images of PVC/halloysite composites showed a homogeneous distribution of the filler in the polymer matrix. The introduction of halloysite leads to a slight increase in Young’s modulus and tensile strength compared to neat PVC, where the increase of both parameters is greater when KHA is used. The incorporation of 1% KHA led to an increase in impact strength, an effect which may be attributed to toughening of the polymer. A slight improvement of the Vicat softening temperature of 2.7 degrees C for PVC/HA and heat deflection temperature of 2.4 C for PVC/KHA was also ascertained for PVC modified with 10 wt% of filler.

11

Microscopic Analysis of the Aluminium Castings Produced with the use of Polymer Composite Patterns

Czarnecka-Komorowska Dorota, Gawdzińska Katarzyna, Popielarski Paweł

Archives of Foundry Engineering

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2022

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Vol. 22, iss. 3

113--117

EN

The paper presents a microscopic analysis of the surface and fracture of aluminium castings produced using the lost-wax method for patterns made of a composite material, i.e. polyethylene with the addition of bentonite. Castings are made of AlSi7 aluminium alloy (silumin) in a plaster mould. A new type of polymer waxes enriched with bentonite was used to obtain new composites, minimizing the defects caused by the casting production process. The castings were made in the centrifugal casting process. The prepared plaster moulds were removed from the furnace and poured with liquid aluminium alloy (AlSi7) at 750°C. The surface and fracture of the castings was analysed using an optical digital microscope type VHX-7000 manufactured by KEYENCE. It has been proven that the studied castings feature surface defects (raw surface defects) in the form of high roughness and the presence of bentonite inclusions classified as casting contamination. During the tests, shape defects related to mechanical damage were also.

12

Study on the Machinability of Glass, Carbon and Aramid Fiber Reinforced Plastics in Drilling and Secondary Drilling Operations

Ciecieląg Krzysztof

Advances in Science and Technology. Research Journal

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2022

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Vol. 16, no 2

57--66

EN

Composite materials are usually subjected to machining processes, especially when they are used to for the aviation and automotive industries. Apart from side surface milling and face milling, these materials are subjected to machining to make holes and countersinking holes, cuts of complex shape, recesses, and grooves. One of the many machining methods for polymer composites is drilling. The accuracy of a drilled hole is very important for operational reasons, because it has impact on the quality and strength of the connection between polymer composite elements and structural elements. This paper shows the results of a study investigating the impact of drilling and secondary drilling as well as technological drilling parameters on the maximum feed force, surface roughness and hole quality. Holes were drilled in glass, carbon and aramid fiber reinforced plastics. The study has shown that the highest maximum feed force occurs when drilling in aramid fiber reinforced plastic. The lowest values of the maximum feed force were obtained when drilling in glass fiber reinforced plastic. The influence of drilling parameters on surface roughness during drilling holes in composite materials was also determined. The highest values of roughness parameters were obtained in the machining of aramid fiber reinforced plastic, while the lowest roughness parameters were obtained on the hole surface when drilling in carbon fiber reinforced plastic.

13

Effect of Water Absorption on Tribological Properties of Thermoplastics Matrix Composites Reinforced with Glass Fibres

Walczak Mariusz, Szala Mirosław, Pieniak Daniel

Advances in Science and Technology. Research Journal

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2022

|

Vol. 16, no 2

232--239

EN

The present work investigated the water absorption of thermoplastic matrix composites and their effect on tribological behaviour. Four thermoplastic composites were researched based on Polyamide 6 and Polyamide 66 matrix reinforced with glass fibres. The composites fabricated using the injection moulding technique were immersed in distilled water at room temperature for a water absorption test for 14 days. Dry sliding wear was conducted using a pin-on-disc trbiotester. The coefficient of friction (COF) and the wear rate (K) was determined. The sliding trace was analyzed using a scanning electron microscope (SEM) to reveal the sliding wear mechanism of composites. Studies have shown that polyamide PA6 based composites are less prone to absorb water than PA66 matrix. In addition, the composites richer in fibreglass exhibit lower water absorption. Tribological results indicated that polymer composites showed higher COF and K after water absorption testing. Mean COF and K were in the range of 0.071÷0.321 and 2.51∙10-6÷1.81∙10-4 mm3N-1m-1, respectively. Wear traces SEM analysis revealed that untreated samples are characterized by less intense abrasive and adhesive wear mode than the hydrated polymers. Besides, the degradation process took place primarily at the polymer matrix-fibreglass interfaces.

14

Analiza właściwości termicznych i mechanicznych polietylenu z dodatkiem mączki drzewnej

Gnatowski Adam, Kijo-Kleczkowska Agnieszka, Suchecki Łukasz

Rynek Energii

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2021

|

Nr 2

49--53

PL

Praca podejmuje analizę oddziaływania dodatku napełniacza na właściwości termomechaniczne wyprasek kompozytowych polietylenu HDPE. Napełniacz, w postaci mączki drzewnej, stanowił masowo 2,5; 5 i 10% kompozytu. Wykonano badania próbek pod kątem wytrzymałości na rozciąganie, właściwości termomechanicznych metodą DMTA oraz właściwości termicznych metodą DSC. W odniesieniu do wyprasek z polietylenu, próbki kompozytowe miały zbliżone wartości wytrzymałości na rozciąganie, charakteryzowały się nieznacznie wyższą wartością modułu zachowawczego i wykazały zbliżony zakres temperatury topnienia fazy krystalicznej.

EN

The paper analyzes the impact of filler addition on the thermomechanical properties of HDPE polyethylene composite moldings. The filler, in the form of wood flour, constituted 2.5, 5 and 10% by mass of the composite. The samples were tested in terms of tensile strength, thermomechanical properties by the DMTA method, and thermal properties by the DSC method. With regard to purely polyethylene moldings, the composite samples showed lower tensile strength, higher modulus, and a change in the range of the melting point of the crystalline phase and the degree of crystallinity.

15

The new functional filler TiO2-SiO2/polyhedral oligomeric hybrid silsesquioxane as a potential modifier of polyethylene

Kloziński Arkadiusz, Ambrożewicz Damian, Jakubowska Paulina, Dudziec Beata, Andrzejewska Ewa, Marciniec Bogdan, Jesionowski Teofil

Polimery

|

2021

|

T. 66, nr 11-12

602--610

EN

The paper presents preliminary application studies of the innovative TiO2 -SiO2 / POSS filler as a potential low-density polyethylene modifier. It was found that the addition of the filler increases the stiffness and hardness of the composite and slightly changes the intensity of its color.

PL

Przedstawiono wstępne badania aplikacyjne innowacyjnego napełniacza TiO2 -SiO2 /POSS jako potencjalnego modyfikatora polietylenu małej gęstości. stwierdzono, że dodatek napełniacza powoduje wzrost sztywności i twardości kompozytu oraz nieznacznie zmienia intensywność jego barwy.

16

Wpływ rodzaju napełniacza naturalnego na strukturę i własności kompozytów polimerowych

Nowak Agnieszka J., Drynda Paulina, Wolny Justyna

Modelowanie Inżynierskie

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2021

|

T. 42, nr 73

21--29

PL

W artykule przedstawiono zagadnienia dotyczące kompozytów polimerowych z naturalnym wzmocnieniem, w tym kompozytów biodegradowalnych. W ramach pracy własnej wytworzono kompozyty o osnowie polimeru biodegradowalnego BIOPLAST GS 2189 z napełniaczem w postaci mączki drzewnej oraz odpadowego przemiału kawy o zawartości do 20% obj. Próbki do badań uformowano w technologii wtrysku. Zbadano wpływ rodzaju oraz zawartości procentowej napełniacza na strukturę, własności mechaniczne oraz nasiąkliwość wody wytworzonych materiałów.

EN

The article presents issues related to polymer composites with natural reinforcement, including biodegradable composites. As part of our own work, composites based on the biodegradable polymer BIOPLAST GS 2189 with a filler in the form of wood flour and waste coffee ground with a content of up to 20% by volume were produced. The test specimens were formed in the injection technology. The influence of the type and percentage of the filler on the structure, mechanical properties and water absorption of the produced materials was investigated.

17

Influence of fibre loading and surface treatment on the impact strength of coir polyester composites

Karthikeyan S.

Archives of Materials Science and Engineering

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2021

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Vol. 107, nr 1

16--20

EN

Purpose: In this work, coir fibre with varying fibre content was selected as reinforcements to prepare polymer-based matrices and the problem of reduced fibre-matrix interfacial bond strength has been diluted by chemical treatment of coir fibres with alkali solution. Design/methodology/approach: The effect of fibre loading, solution concentration and soaking time on the impact strength of the composites were analyzed using statistical techniques. Response Surface Methodology (RSM) approach was used to model and optimize the impact properties of coir-polyester composites. Findings: The impact strength of coir fibre reinforced polyester composite depends mainly on the fabrication parameters such as fibre-polyester content, soaking time, concentration of soaking agent and adhesive interaction between the fibre and reinforcement. Research limitations/implications: The mechanical properties of any coir polyester composite depend on the nature bonding between the fibre and reinforcement. The presence of cellulose, lignin on the periphery of any natural fibre reduces the bonding strength of the composite. This limitation is overcome by fibre treatment over sodium hydroxide to have better impact properties. Practical implications: Now days, natural fibre reinforced composites are capable of replacing automotive parts, subjected to static loads such as engine Guard, light doom, name plate, tool box and front panels etc. These materials can withstand any static load due to its higher strength to weight ratios. Originality/value: The effect of fibre loading, solution concentration and soaking time on the impact strength of the composites were analyzed using statistical techniques. Response Surface Methodology (RSM) approach was used to model and optimize the impact properties of coir-polyester composites. The impact strength of NaOH impregnated coir fibre reinforced polyester composites was evaluated.

18

Micro-machining of UHMWPE composites reinforced with carbide fillers

Gürgen Selim, Sofuoğlu Mehmet Alper

Archives of Civil and Mechanical Engineering

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2021

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Vol. 21, no. 4

189--202

EN

Polymer matrix composites (PMCs) have become one of the most widely used engineering materials due to both the developments in polymers and advanced fillers. It is expected that polymer composites will take their final shape during the production phase, which means that they are not required to undergo new processes. However, in some applications, machining operations, such as turning, milling, grooving and hole drilling, cannot be avoided and thus, finishing operations must be applied to these materials. Since these materials have complex microstructures, finishing operations may cause situations that adversely affect engineering properties, such as matrix cracking, delamination, debonding, etc. In this study, micro-milling operations were performed for recently developed ceramic reinforced polymer composites. Three different spindle speeds were used while feed rate and cutting depth were kept constant in the operations. The composites were produced from powdered UHMWPE and silicon carbide particles. Several parameters were varied in the production of the composites, such as molding pressure, filler loading and filler size. The investigated outputs were cutting temperature and surface roughness, whereas machined surfaces and chip morphologies were also investigated via microscopy analyses. In the final stage, regression analyses were performed to investigate the relationships between the process parameters. According to the results, ceramic reinforced polymer composites exhibit different machinability properties than fiber-reinforced ones due to hard fillers and low melting point of UHMWPE.

19

Biokompozyty polimerowe na bazie polilaktydu i włókien celulozowych

Fabijański Mariusz

Przemysł Chemiczny

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2020

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T. 99, nr 6

923--926

PL

Badano proces wtrysku PLA z różnymi zawartościami włókien celulozowych (dwa typy) w otwartej formie wtryskowej z gniazdem w kształcie spirali Archimedesa. Oznaczono właściwości mechaniczne poszczególnych kompozytów. Stwierdzono, że proces ten nie stwarza problemów technologicznych. Właściwości mechaniczne ulegają pogorszeniu, jednak nie dyskwalifikuje to badanych materiałów do zastosowań, w których wyrób nie jest mocno obciążony mechaniczne.

EN

Two types of cellulose fibers (10-40% by mass) were mixed with polylactide by an open-ended spiral-shaped injection molding. Tensile strength, impact strength and hardness of the composites were detd. The addn. of cellulose fibers resulted in deterioration of all mech. properties of polylactide but the composites can be used in some applications where any high mech. strength of the product is required.

20

Validation process for computational model of full-scale segment for design of composite footbridge

Ferenc Tomasz, Mikulski Tomasz

Polish Maritime Research

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2020

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nr 2

158--167

EN

Experimental tests and numerical simulations of a full-scale segment of a foot and cycle bridge made of polimer composites are presented in the paper. The analysed structure is made of sandwich panels, which consist of glass fibre reinforced polymer (GFRP) multi-layered laminate faces and a PET foam (obtained from recycling) core. The dimensions of the segment cross-section are the same as for the target footbridge; however, span length was reduced to 3 m. The experimental tests were conducted in a laboratory of the Faculty of Ocean Engineering and Ship Technology at Gdansk University of Technology. A single vertical force was generated by a hydraulic cylinder and was applied to the platform of the structure. The experimental tests were supported by numerical analyses performed in Femap with NX Nastran software by means of the finite element method (FEM). Results obtained in the computational model were compared with results from experiments. Thus, the numerical model was validated and the obtained conclusions were used in the next step of the design process of a composite footbridge with a span length of 14.5 m.