Person: SANCAK, ERHAN
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SANCAK
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ERHAN
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Publication Metadata only Effect of silane coupling treatments on mechanical properties of epoxy based high-strength carbon fiber regular (2 x 2) braided fabric composites(WILEY, 2021) SANCAK, ERHAN; Eryilmaz, Oguz; Sancak, ErhanBraiding technique is one of the most cost-effective and versatile methods to manufacture braided preforms for producing textile reinforced composites. Carbon fiber is one of the most common reinforcing fibers having high strength and modulus used in high-performance composites. In this study, epoxy resin was modified with 3-aminopropyltriethoxysilane (APTES) and 3-aminopropylmethyldimethoxysilane (APMDMS) in order to enhance interfacial adhesion between matrix and carbon fiber. Composites were produced by vacuum-assisted resin infusion method using braided fabrics which were manufactured from a high-strength standard modulus type of carbon fiber (T700S) by using a radial braiding machine. Epoxy resin was treated with silane at different concentrations from 0.0% to 1.0%. According to the mechanical results, the ideal (optimum) concentration of APTES and APMDMS for the matrix modification has been around 0.5 wt% of the epoxy system. Also, the mechanical properties of APTES-treated epoxy composites are slightly higher than those of APMDMS-treated epoxy composites at the same concentration. When it is compared to silane untreated composite, 0.5 wt% of APTES/APMDMS silane treated epoxy/carbon braided composites have led to an increase of 7.71/6.16% and 7.65/6.05% in tensile and flexural strength while the corresponding increase has resulted in 17.48/13.51% and 16.63/13.33% in terms of tensile and flexural modulus, respectively. Impact testing results indicate that 0.5 wt% of APTES and APMDMS composites are improved 6.87% and 4.31% compared to untreated composites, respectively.Publication Open Access Analyses of the mechanical, electrical and electromagnetic shielding properties of thermoplastic composites doped with conductive nanofillers(SAGE PUBLICATIONS LTD, 2018-05) SANCAK, ERHAN; Yilmaz, Ali Can; Ozen, Mustafa Sabri; Sancak, Erhan; Erdem, Ramazan; Erdem, Ozlem; Soin, NavneetThe purpose of this study is to observe effect of incorporating vapor-grown carbon nanofibers with various amounts in polyvinylidene fluoride matrix in terms of mechanical strength and electromagnetic shielding effectiveness. Thermoplastic conductive nanocomposites were prepared by heat-pressed compression molding. Vapor-grown carbon nanofibers were utilized at various weight ratios (1wt.%, 3wt.%, 5wt.%, and 8wt.%) as conductive and reinforcing materials. Polyvinylidene fluoride was used as a thermoplastic polymer matrix. Scanning electron microscopic analysis was conducted in order to characterize the morphology and structural properties of the nanocomposites and results revealed well dispersion of carbon nanofibers within the matrix for all concentrations. Mechanical characteristics were investigated according to standards. Findings proved that overall increments of 16%, 37.5%, and 56% were achieved in terms of tensile strength, elasticity modulus, and impact energy, respectively, where a total reduction of 44.8% was observed in terms of elongation for 8wt.% vapor-grown nanofiber matrix compared to that of 0wt.%. Electromagnetic shielding effectivenesses of the nanocomposites were determined by standard protocol using coaxial transmission line measurement technique in the frequency range of 15-3000 MHz. It was observed that resistance, sheet resistance, and resistivity of nanocomposites depicted substantial reduction with the increment in nanofiber content. Nevertheless, it was observed that nanofiber content, dispersion, and network formation within the composites were highly influent on the electromagnetic shielding effectiveness performance of the structures.Publication Metadata only Analysis of EMSE and mechanical properties of sputter coated electrospun nanofibers(ELSEVIER SCIENCE BV, 2016) SANCAK, ERHAN; Erdem, Ramazan; Ilhan, Mustafa; Sancak, ErhanPA6 nanofibers were electrospun successfully and sputter coated with gold and palladium to create functional nanofibrous membranes that possess electromagnetic shielding ability. Properties of the electrospinning solutions were analyzed in terms of viscosity, conductivity and pH values. Coating thicknesses of the nanofibrous membranes were determined as 50 nm and 100 nm. Morphology of the nanofibrous membranes were observed by SEM analysis. Elemental composition of the specimens was explored by using Energy Dispersive Spectroscopy. Results revealed that defect free and uniform nanofibers were obtained, and the diameters of the fibers were changed after coating. Tensile strength and elongation measurements confirmed that the mechanical characteristics of the nanofibrous membranes were merely altered after coating. Electromagnetic Shielding Effectiveness (EMSE) of the nanofibers was determined according to the ASTM D4935-10 protocol by using coaxial transmission line measurement technique in the frequency range of 15-3000 MHz. It was observed that 100 nm coated membrane performed better EMSE than uncoated and 50 nm coated nanofibrous membranes. (C) 2016 Elsevier B.V. All rights reserved.Publication Metadata only Investigation of electromagnetic shielding properties of needle-punched nonwoven fabrics with stainless steel and polyester fiber(SAGE PUBLICATIONS LTD, 2013) BEYİT, ALİ; Ozen, Mustafa Sabri; Sancak, Erhan; Beyit, Ali; Usta, Ismail; Akalin, MehmetIn this study, electromagnetic shielding properties of needle-punched nonwoven fabrics were investigated. The paper evaluates and compares the electromagnetic shielding of needle-punched nonwoven fabrics produced from stainless steel/polyester and normal polyester fibers. Stainless steel/polyester fiber and normal polyester fiber were blended at specified ratios in the experimental study. Webs were produced from the fibers with the carding machine and then bonded with the needle-punching machines. The thickness and electromagnetic shielding properties of the needle-punched fabrics were tested. An electromagnetic shielding effectiveness (EMSE) device was used for measuring the electromagnetic shielding. The experimental study indicated that as the conductive stainless steel fiber ratio in nonwoven fabrics increases, the EMSE also increases at low, medium and high frequencies. Satisfactory electromagnetic shielding values were obtained at wide bandwidth, i.e. 1200-3000 MHz. The highest EMSE values of the needle-punched nonwoven fabric with 25% conductive steel fiber were, respectively, 6 dB at 0-300 MHz low frequency, 12 dB at 300-1200 MHz medium frequency and 18 dB at 1200-3000 MHz high frequency. It was found that 90% of electromagnetic waves were shielded by nonwoven fabric at high frequencies, 85% at medium frequencies and 80% at low frequencies.Publication Metadata only The Effects of Fabric and Conductive Wire Properties on Electromagnetic Shielding Effectiveness and Surface Resistivity of Interlock Knitted Fabrics(KOREAN FIBER SOC, 2018) SANCAK, ERHAN; Sancak, E.; Akalin, M.; Usta, I.; Yuksek, M.; Ozen, M. S.Our aim in this study was to investigate the effects of course density, yarn linear density and thickness and type of conductive wire on electromagnetic shielding effectiveness. Metal/cotton conductive composite yarns were produced by the core-spun technique on the ring spinning machine, involving stainless steel, copper and silver coated copper wires with 40 mu m, 50 mu m, 60 mu m thicknesses and Ne10/1 and Ne20/1 count yarns. The interlock fabrics were knitted on a 7G flat knitting machine with the three different machine settings. The EMSE and the surface resistivity of knitted fabrics were measured by the co-axial transmission line method according to the ASTM-D4935-10 standard in the frequency range from 15 to 3000 MHz and by the ASTM D257-07 standard, respectively. It was observed that all fabrics shielded around 95 % of electromagnetic waves at low frequencies, 80 % at medium frequencies and 70 % at high frequencies. Increasing the course density and thickness of conductive wire in interlock knitted fabrics increased the EMSE correspondingly. The knitted fabrics that had been produced with high yarn count showed greater EMSE because there was less isolation. The effect of the metal wire type was highly significant between 15 and 600 MHz.Publication Metadata only Development of bio-composite structures for Interior noise reduction in automobiles(2018-12-07) PARS, ABDULKADİR; SANCAK, ERHAN; BEYİT, ALİ; ÖZEN, MUSTAFA SABRİ; YÜKSEK, METİN; USTA, İSMAİL; PARS A., SANCAK E., BEYİT A., ÖZEN M. S. , YÜKSEK M., USTA İ.Publication Metadata only Investigation of electromagnetic shielding properties of boron, carbon and boron-carbon fibre hybrid woven fabrics and their polymer composites(TAYLOR & FRANCIS LTD, 2017) SANCAK, ERHAN; Mistik, Sleyman Ilker; Sancak, Erhan; Ovali, Sabih; Akalin, MehmetThe growth of the electronic industry and the widespread use of electronic equipment in communications, computations, automations, biomedicine, space and other purposes have led to many electromagnetic interference (EMI) problems as systems operate in close proximity. It is likely to become more severe in the future, unless proper EMI control methodology and techniques are used to meet the electromagnetic compatibility requirements. In recent years, electromagnetic (EM) waves in the 1-10 GHz range are broadly used in wireless communication tools and local area networks. In the future, the usable range of EM waves will tend to shift further to higher frequency regions with the development of information technology as well as electronic devices. As a consequence, the seriousness of problems such as EMI of electronic devices and health issues is ever rising. In this study, electromagnetic shielding effectiveness, absorbance and reflectance properties of the boron, carbon and boron-carbon plain woven fabrics and boron/polyester, carbon/polyester, and boron-carbon/polyester hybrid composites were investigated. Using a coaxial transmission line holder set-up, the (EMSE), reflectance and absorbance of various fabrics and composites were carried out in the frequency range from 15 to 3000 MHz.Publication Metadata only Investigation of the Electromagnetic Shielding Effectiveness of Needle Punched Nonwoven Fabrics Produced from Stainless Steel and Carbon Fibres(INST CHEMICAL FIBRES, 2018) SANCAK, ERHAN; Ozen, Mustafa Sabri; Usta, Ismail; Yuksek, Metin; Sancak, Erhan; Soin, NavneetThe electromagnetic shielding effectiveness (EMSE) of needle punched, nonwoven fabrics produced using staple stainless steel and carbon fibres was investigated. Utilising carding and large scale industrial type needle punching machines, webs of staple stainless steel and carbon fibres were produced, which were subsequently bonded on the needle punching machine at approximately 132 punches/cm(2) and 13.5 mm needle penetration depth. The effect of varying the carbon fibre content was studied by varying the blend ratio of stainless steel and carbon fibres between 5-20%. EMSE measurements of as-produced needle punched nonwoven fabrics were carried out using the coaxial transmission line method (ASTM D4935-10) in the frequency range of 15-3000 MHz. Within the range, the EMSE values were enhanced from 22.3 dB (95/5, stainless steel/carbon) to 44.7 dB (80/20, stainless steel/carbon), which was attributed to the enhanced conductivity of the fabrics. In fact, the surface resistivity of the samples decreased from 5.80E + 3 Omega to 2.43E + 2 Omega, enhanced for 95: 5 and 80: 20 stainless steel/carbon blends.Publication Metadata only Electrospinning of single and multilayered scaffolds for tissue engineering applications(TAYLOR & FRANCIS LTD, 2017) BEYİT, ALİ; Erdem, Ramazan; Yuksek, Metin; Sancak, Erhan; Atak, Onur; Erginer, Merve; Kabasakal, Levent; Beyit, AliOptimized electrospinning conditions were applied to produce single and multilayered (ML) scaffolds composed of polycaprolactone, collagen and elastin. The ML scaffold was cross-linked with glutaraldehyde to increase the stability. Morphological and structural characteristics of the scaffolds were measured by SEM and FTIR analyses. Results revealed that polymers combined to each other well and uniform fibers were obtained with the diameters ranging from 156 +/- 53 to 1536 +/- 293 nm. Contact angle measurements were performed to investigate the hydrophilic character of each structure. It was observed that incorporation of the natural polymers into the blends increased the hydrophilicity. Mechanical tests proved that collagen contributed to fabricate stiffer structures while elastin provided more elasticity. Biocompatibility of the scaffolds was examined by SEM analysis and WST-1 test with mouse fibroblast cells (L929) in vitro. Results exhibited that the addition of natural polymers increased the cell growth, and none of the single and ML scaffolds presented cytotoxic effect.Publication Metadata only Investigation of electromagnetic shielding effectiveness of needle punched nonwoven fabrics with staple polypropylene and carbon fibres(TAYLOR & FRANCIS LTD, 2016) SANCAK, ERHAN; Ozen, Mustafa Sabri; Sancak, ErhanConductive needle punched nonwoven fabrics are developed from staple polypropylene (PP) and varying weight fractions (10, 20 and 30 wt.%) of staple carbon fibres. A fibrous webs of staple PP and carbon fibres were formed at a wool-type carding machine, and these webs subsequently bonded on needle punching machine with 132 punches/cm(2) and 13.5 mm needle penetration depth. The electromagnetic shielding effectiveness (EMSE), absorption and reflection characteristics of as-produced needle punched nonwoven fabrics were determined using a network analyser as specified in ASTM D4935-10 in the frequency range 15-3000 MHz. The surface resistivity measurements were carried out in accordance with ASTM D 257-07 standard. These results indicate that the EMSE values increase incrementally with frequency in the 15-3000 MHz range. The nonwoven sample with 30 wt.% carbon fibre showed the lowest surface resistivity of 3.348 k Omega and corresponding highest EMSE of similar to 42.1 dB in the 3000 MHz frequency range. In comparison, the highest EMSE values from 10 to 20 wt.% staple carbon fibre were found to be 15.6 and 32.2 dB in the 3000 MHz frequency, respectively. It was observed that the absorbance and reflectance curves of each nonwoven fabric move at opposite directions to each other. It was found that as the amount of carbon fibre in the nonwoven fabric increases, absorbance values decrease, but reflectance values increase. The resultant nonwoven fabric samples are expected to be used as garment interlining after thermal bonding and wall interlayer in the future.