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1

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

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2022

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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.

2

Influence of the Soaking Time on the Mechanical Properties of Coir as a Natural Composite Reinforcement

Arsyad Muhammad, Soenoko Rudy, Arman Arman

Fibres & Textiles in Eastern Europe

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2020

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Vol. 28, no. 6 (144)

98--103

EN

This study aimed to determine the effect of the long soaking of coir in sodium hydroxide solution on its mechanical properties. The materials used, namely coir, sodium hydroxide solution, polyester matrix, catalyst, and aquades. The coir was soaked in a sodium hydroxide solution for 1, 5, 7, 9, and 11 hours. After that, coconut fibre was washed using distilled water, and then dried in an oven at 90 °C for 5 hours. Next, a single fibre tensile and pull out test was performed. Based on the results and discussion, it was concluded that immersing coconut fibre in sodium hydroxide solution for 7-hours gave the maximum tensile strength and interfacial shear strength of 223.91 N/mm2, and 9.8 N/mm2, respectively Coir as a composite reinforcement has the potential to be used for engineering material such as ceiling boards and fishing boat walls.

PL

Celem pracy było określenie wpływu długotrwałego moczenia włókna kokosowego w roztworze wodorotlenku sodu na jego właściwości mechaniczne. Zastosowane materiały, a mianowicie: kokos, roztwór wodorotlenku sodu, matryca poliestrowa i katalizator. Włókno kokosowe moczono w roztworze wodorotlenku sodu przez: 1, 5, 7, 9 i 11 godzin. Następnie włókno kokosowe przemyto wodą destylowaną i suszono w piecu w temperaturze 90 °C przez 5 godzin. Następnie przeprowadzono pojedynczą próbę rozciągania włókna. Na podstawie wyników i dyskusji stwierdzono, że zanurzenie włókna kokosowego w roztworze wodorotlenku sodu na 7 godzin dało efekt w postaci maksymalnej wytrzymałości na rozciąganie i międzyfazowej wytrzymałości na ścinanie wynoszących odpowiednio 223,91 N/mm2 i 9,8 N/mm2. Tak wzmocnione włókno kokosowe ma szansę na użycie jako zbrojenie kompozytowe i potencjał do wykorzystania w materiałach inżynieryjnych, takich jak płyty sufitowe i ściany łodzi rybackich.

3

Surface modification of PBO fiber by electrostatic discharge for composites

Wu G. M., Shyng Y. T.

Archives of Materials Science and Engineering

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2007

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Vol. 28, nr 12

722-728

EN

Purpose: PBO fibers provide great potential applications as reinforcement fibers for advanced composites due to the excellent thermal resistance and specific stiffness and strength. However, the interfacial adhesion between reinforcing fiber and polymer matrix in a composite system is a primary factor for the stress transfer from matrix to fiber. In this paper, the effects of surface treatment on the modification of PBO fiber and its composite materials have been investigated using electrostatic discharge under atmospheric pressure. The surface treatment process has been designed to improve fiber/matrix interfacial bonding quality while providing minimum alteration to the bulk characteristics of the reinforcement fiber. Design/methodology/approach: Both as-spun (AS) and high-modulus (HM) PBO fibers were surface treated and characterized in this study. The characterization techniques included scanning electron microscopy, MTS tensile tester, dynamic contact angle analysis system and microbond pull-out tests. Findings: The results showed that PBO fibers exhibited-10% reduction in tensile strength after the proposed treatment process. The AS fiber surface free energy could be increased from 49.90 mJ/m² to 65.42 mJ/m² (+31%) and the HM fiber surface free energy could be increased from 46.20 mJ/m² to 65.36 mJ/m² (+41%). The interfacial shear strength between PBO fiber and the epoxy matrix was improved to 41.6 MPa (+20%) for AS fiber system, and it improved to 40.1 MPa (+23%) for HM fiber system. The composite failure mode also shifted from fiber/matrix interface adhesive failure to partly cohesive failure. Research limitations/implications: The composite interfacial shear strength was improved through the increased surface free energy of PBO fiber. The more cohesive failure mode allowed more energy to be dissipated during failure. Originality/value: The proposed electrostatic discharge treatment process could improve the surface characteristics of PBO fiber and the applications in advanced composites.

4

Surface modification of PBO fiber by electrostatic discharge for composites

Wu G. M., Shyng Y. T.

Journal of Achievements in Materials and Manufacturing Engineering

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2006

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Vol. 17, nr 1-2

169--172

EN

Purpose: PBO fibers provide great potential applications as reinforcement fibers for advanced composites due to the excellent thermal resistance and specific stiffness and strength. However, the interfacial adhesion between reinforcing fiber and polymer matrix in a composite system is a primary factor for the stress transfer from matrix to fiber. In this paper, the effects of surface treatment on the modification of PBO fiber and its composite materials have been investigated using electrostatic discharge under atmospheric pressure. The surface treatment process has been designed to improve fiber/matrix interfacial bonding quality while providing minimum alteration to the bulk characteristics of the reinforcement fiber. Design/methodology/approach: Both as-spun (AS) and high-modulus (HM) PBO fibers were surface treated and characterized in this study. The characterization techniques included scanning electron microscopy, MTS tensile tester, dynamic contact angle analysis system and microbond pull-out tests. Findings: The results showed that PBO fibers exhibited -10% reduction in tensile strength after the proposed treatment process. The AS fiber surface free energy could be increased from 49.90 mJ/m2 to 65.42 mJ/m2(+31%) and the HM fiber surface free energy could be increased from 46.20 mJ/m2 to 65.36 mJ/m2 (+41%). The interfacial shear strength between PBO fiber and the epoxy matrix was improved to 41.6 MPa (+20%) for AS fiber system, and it improved to 40.1 MPa (+23%) for HM fiber system. The composite failure mode also shifted from fiber/matrix interface adhesive failure to partly cohesive failure. Research limitations/implications: The composite interfacial shear strength was improved through the increased surface free energy of PBO fiber. The more cohesive failure mode allowed more energy to be dissipated during failure. Originality/value: The proposed electrostatic discharge treatment process could improve the surface characteristics of PBO fiber and the applications in advanced composites.

5

Wpływ modyfikacji powierzchni tlenku glinu na zwilżalność i wytrzymałość połączenia w układzie Cu/AL203

Książek M., Sobczak N., Mikułowski B., Radziwiłł W., Wójcik M.

Odlewnictwo - Nauka i Praktyka

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2003

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R. 5, nr 1

4-9

PL

Przeprowadzono badania wpływu cienkiej warstwy Ti o grubości 800 nm, naniesionej na podłoże z tlenku glinu (metodą PVD) na zwilżalność i własności mechaniczne połączenia w układzie Cu/Al2O3. Metodą kropli leżącej przeprowadzono badania porównawcze kinetyki zwilżania podłoża z pokryciem i bez pokrycia przez ciekłą Cu (99,99%) w temperaturze 1373 K i 1423 K, w warunkach próżni dynamicznej rzędu 0,2 mPa. Badania oddziaływania w układzie Cu/Ti/Al2O3 wykazały, że modyfikacja powierzchni podłoża tlenku glinu tytanem polepsza zwilżalność w układzie Cu/Al2O3. Pomiar wytrzymałości połączenia przeprowadzono metodą ścinania próbek po badaniach zwilżalności, wykorzystując własną metodykę. Wyniki próby ścinania wykazały, że istnieje wyraźna zależność wytrzymałości na ścinanie od temperatury i kąta zwilżania tylko w układzie miedź-pokrycie-tlenek glinu, tj. niższej wartości kąta zwilżania odpowiada wyższa wartość wytrzymałości na ścinanie. Badania strukturalne w układzie Cu/Ti/Al2O3 wykonane metodą mikroskopii optycznej oraz skaningowej wykazały rozpuszczanie pokrycia Ti w Cu i formowanie struktury granicy rozdziału, odpowiadającej wyższej wytrzymałości na ścinanie w porównaniu do układu typu Cu/Al2O3. Przeprowadzone badania oddziaływania tlenku glinu z nałożoną warstwą tytanu z ciekłą Cu w powiązaniu z pomiarem wytrzymałości połączenia pozwoliły na ustalenie optymalnych parametrów dla procesu wytwarzania połączeń metal-ceramika o żądanej strukturze i własnościach mechanicznych.

EN

The subject of the work was to study the effect of Ti thin film on alumina substrates on wetting and bond strength properties in Cu/Al2O3 couples. Applying the sessile drop method, the wetting behaviour of molten Cu (99,99%) on coated and uncoated alumina substrates was studied at 1373 K and 1423 K under a vacuum of 0.2 mPa. The sessile drop samples were used to examine the interface structure and shear strength. The Ti layer of 800 nm thickness improves the wetting properties in Cu/Al2O3 and for all couples the temperature increase results in lower values of contact angle. The shear test demonstrates different wetting-bond strength relationship for coated and uncoated couples. Contrary to Cu/Ti/Al2O3, in Cu/Al2O3 couples higher shear strength was noted for higher contact angle, corresponding to lower temperature of wettability test. The structure characterisation of interfaces by means of optical microscopy and electron microscopy equipped with spectrometric system for microanalysis of chemical composition suggests that positive effect of Ti layer on the improvement of both wetting and bond strength properties in Cu/Al2O3 system results from a favourable change of structure and chemistry of the interface.