Sıcak Suda Yaşlandırılan Cam Fiber-Epoksi Kompozitlerin Tabakalar arası Kayma Dayanımındaki Değişimlerin İncelenmesi

Konferans Bildirisi -- Teorik ve Uygulamalı Mekanik Türk Milli Komitesi, 2015Conference Paper -- Theoretical and Applied Mechanical Turkish National Committee, 2015Bu çalışmada, cam fiber takviyeli epoksi kompozitlerin tabakalararası kayma dayanımına sıcak suyun etkisi incelenmiştir. Kompozit üretiminden önce cam fiberlerin yüzeyine farklı derişimlerde silan yüzey işlemi uygulanmıştır. Kompozitlerin kayma dayanımına su sıcaklığının, kompozitlerin suda bekletilme süresinin ve kullanılan silan derişiminin etkisi tespit edilmiştir. Su sıcaklıkları 25, 50 ve 75 oC ve suda bekletilme süresi 24, 48 ve 72 saat olarak seçilmiştir. Fiber yüzey işlemlerinde silan uyumlaştırıcı ajanı olarak ?-glycidoxypropyltrimethoxysilan (?-GPS) kullanılmıştır ve silan uyumlaştırıcı ajanı derişimi toplam çözeltide %0,1 ile %0,5 arasında değiştirilmiştir. Su sıcaklığı ve kompozitlerin suda bekletilme süresi arttıkça kompozitlerin tabakalararası kayma dayanımının da azaldığı belirlenmiştir. %0,5 ?-GPS silan ile yüzey işlemine tabi tutulmuş cam fiber takviyeli epoksi kompozitler sıcak suya karşı en iyi dayanımı göstermiştir.In this study, effect of hot water aging on interlaminar shear strength of glass fiber reinforced epoxy composites was investigated. Silane treatments at different concentrations were applied to surface of glass fibers before composite production. Effect of water temperature, holding duration in water of composites and used silane concentration on interlaminar shear strength was determined. 25, 50 and 75 oC as water temperatures and 24, 48 ve 72 hours as holding duration in water were selected. ?-glycidoxypropyltrimethoxysilane (?-GPS) as a silane coupling agent was used in the fiber surface treatment and the silane coupling agent concentration was varied from 0.1 to 0.5 % (v/v) in aqueous solution. It was determined that the interlaminar shear strengths of the composites decreased with increasing of water temperature and holding duration in water. 0.5 % ?-GPS silane treated glass fiber reinforced epoxy composite showed the best resistance against hot water

Grafen Takviyeli Biyokompozitlerin Mekanik Ve Termal Özelliklerinin İncelenmesi

Konferans Bildirisi -- Teorik ve Uygulamalı Mekanik Türk Milli Komitesi, 2015Conference Paper -- Theoretical and Applied Mechanical Turkish National Committee, 2015Bu çalışmada kitosan biyopolimeri grafen nanopartikülleri ile takviye edilmiştir. Polimerik kompozitler ağırlıkça farklı oranlarda grafen kullanılarak çözelti döküm tekniği ile hazırlanmıştır. Çekme testleri kompozitlerin çekme dayanımı ve Young modülünü belirlemek için gerçekleştirilmiştir. Ayrıca kitosanın termal iletkenliğine grafenin etkisi tespit edilmiştir. % 2 grafen kitosan içerine katıldığında, kitosanın çekme dayanımı ve Young Modülü sırasıyla % 72 ve % 170 artmıştır. Kompozitlerin termal iletkenliği kitosan ile kıyaslandığında çok daha yüksek olduğu tespit edilmiştir.Chitosan polymer was reinforced with graphene nanoparticles in this study. Polymeric composites were prepared by the solution casting technique using graphene at different weight ratios. Tensile tests were carried out to determine tensile strength and Young’s modulus of the composites. The effect of graphene on thermal conductivity of chitosan was also determined. The tensile strength and Young’s modulus of chitosan increased by approximately 72 % and 170 %, respectively when 3 wt.% of graphene was added into chitosan. The thermal conductivity values of these composites were obtained to be higher in comparison with that of chitosan

Grafit Takviyeli Etil Vinil Asetat (Eva) Kompozitlerin Mekanik Özelliklerine Termal Çevrimin Etkisi

Konferans Bildirisi -- Teorik ve Uygulamalı Mekanik Türk Milli Komitesi, 2015Conference Paper -- Theoretical and Applied Mechanical Turkish National Committee, 2015Bu çalışmada, eriyik harmanlama yöntemi ile farklı grafit miktarlarına sahip grafit/EVA kompozitleri hazırlanmıştır. Grafit/EVA kompozitlerin mekanik özelliklerine termal çevrimin etkisini incelemek için, kompozit numuneleri -25 ile 60 °C sıcaklıkları arasında 50 ve 100 defa termal çevrime tabi tutulmuştur. Yapılan 50 ve 100 termal çevrim sonucunda Grafit/EVA kompozitlerin elastisite modülleri artmıştır.In this study, Graphite/EVA composites having different graphite content were prepared by melt blending process. To investigate the effect of thermal cycles on the mechanical properties of graphite/EVA composites, the composite samples were subjected to the thermal cycle processes for 50 and 100 times between temperatures of -25 °C and 60°C. The moduli of graphite/EVA composites at the end of thermal cycle of 50 and 100 increased

Fiber takviyeli polimer kompozitler mekanik performansinda arayüzeylerin etkisi

Bu çalışmada, fiber yüzey işlemlerinden sonra cam yüzeylerindeki ?-GPS (?-Glycidoxypropyltrimethoxysilan)'ın yapısı analiz edildi ve cam elyaf/epoksi kompozitlerin mekanik özellikleri üzerinde yüzey işlemlerinin etkileri incelendi. Fiber yüzey işlemleri fiber ve matris arasında faydalı bir arayüzey oluşturmak için kullanıldı. Fiber ve matris arasındaki arayüzeysel yapışmayı geliştirmek için cam elyaflar kimyasal ve plazma polimerizasyon yöntemleri kullanılarak yüzey işlemine tabi tutuldu. Kimyasal ve plazma polimerizasyon işlemlerinden sonra cam yüzeylerindeki ?-GPS'in yapısı ve cam yüzeyi ve ?-GPS arasındaki etkileşim Fourier Transform Infrared Spektrometre (FT-IR), temas açısı ölçüm cihazı ve taramalı elektron mikroskobu (SEM) kullanılarak incelendi. Cam yüzeylerinde ?-GPS'in plazma polimerizasyonu ile hazırlanan ince filmlerin özellikleri üstünde plazma gücünün ve maruz kalma zamanının etkisi X-ışını Fotoelektron Spektroskopisi (XPS) ile incelendi. Filmlerdeki fonksiyonel grupların varlığını ortaya çıkarmak için XPS analizlerinden yararlanıldı. Cam yüzeylerindeki filmlerin morfolojileri atomik kuvvet mikroskobu (AFM) ve SEM ile incelendi. Cam elyaf/epoksi kompozitlerin mekanik özellikleri üzerinde fiber yüzey işlemlerinin etkisi incelendi. Kompozitlerin mekanik özellikleri çekme, eğilme ve kısa kirişle kayma testleri ile incelenmiştir. Kompozitlerin kırılma yüzeyleri ayrıca SEM ile incelendi. Kompozitlerin mekanik özellikleri kimyasal ve plazma polimerizasyon işlemleri ile geliştirildi. In this study, structure of ?-GPS (?-glycidoxypropyltrimethoxysilane) on glass surfaces after fiber surface treatments was analyzed and effects of the treatments on mechanical properties of glass fiber/epoxy composites were investigated. Fiber surface treatments were used to create the beneficial interface between the fiber and the matrix. Glass fibers were treated using wet chemical and plasma polymerization processes to improve the interfacial adhesion between fiber and matrix. The structure of ?-GPS on glass surfaces after wet chemical and plasma polymerization processes and the interaction between glass surface and ?-GPS were examined using Fourier Transform Infrared Spectroscopy (FT-IR), contact angle measurement device and Scanning Electron Microscopy (SEM). The influence of plasma power and exposure time on the properties of thin films prepared by plasma polymerization of ?-GPS on the glass surfaces was also investigated by X-ray Photo-electron Spectroscopy (XPS). XPS analyses were utilized to reveal the presence of functional groups in the films. Morphologies of the films on the glass surfaces were observed by Atomic Force Microscopy (AFM) and SEM. The effects of fiber surface treatments on mechanical properties of glass fiber/epoxy composites were investigated. Mechanical properties of the composites were investigated by tensile tests, flexural tests and short beam shear tests. The fracture surfaces of the composites were observed with SEM. Mechanical properties of the composites were improved by wet chemical and plasma polymerization studies

The Improvement of Mechanical Properties of Jute Fiber/LDPE Composites by Fiber Surface Treatment

In this study, the effect of oligomeric siloxane on the mechanical properties of jute fabric-reinforced low-density polyethylene (LDPE) composites is examined. After alkali treatment of jute fabric, oligomeric siloxane treatment is conducted to promote adhesion between jute fiber and polyethylene matrix. Mechanical properties of fabricated composites such as tensile strength, flexural strength, and interlaminar shear strength (ILSS) were evaluated. The tensile strength is observed to increase from 17.5MPa for untreated jute fabric/LDPE composite to 27.7MPa for oligomeric siloxane-treated alkalized jute fabric/LDPE composite. Provided that jute fabric is treated with alkali and oligomeric siloxane, a 39% increase is observed in the flexural strength. It is interesting to note that the effect of siloxane treatment after alkalization procedure of jute fabric on ILSS of jute/LDPE composite is due to the fact that 98% improvement is obtained. It can be observed that the adhesion between jute fiber and LDPE also improves to a great extent through both alkali and oligomeric siloxane treatment, respectively. These results are also confirmed by the SEM observations of fracture surfaces of jute/LDPE composites

Determination of properties of Althaea officinalis L. (Marshmallow) fibres as a potential plant fibre in polymeric composite materials

WOS: 000328801200024The mechanical, thermal, chemical, crystallographic and morphological properties of althaea fibres, extracted from Althaea officinalis L, was examined for the first time in this study. A. officinalis L. was obtained from Mordogan, Izmir (Turkey). After extraction process, lignin, cellulose and hemicellulose contents of althaea fibres were identified. Fourier transform infrared and X-ray photoelectron spectroscopy were utilized for surface functional groups of althaea fibres. By using X-ray diffraction analysis, CI value for althaea fibre is obtained to be 68%. The images of scanning electron microscopy were taken for observation of morphology of althaea fibres. The tensile modulus and tensile strength values of althaea fibre were obtained by single fibre tensile tests as 415.2 MPa and 65.4 GPa, respectively. Thermogravimetric analysis showed that thermal degradation of the fibre begins at approximately 220 degrees C. Besides, by pulling out the althea fibre from the embedded high density polyethylene, interfacial shear strength value was determined to be 8.16 MPa. The results suggest that the althaea fibre can be used in composite applications as a natural reinforcement material. (C) 2013 Elsevier Ltd. All rights reserved

Extraction and properties of Ferula communis (chakshir) fibers as novel reinforcement for composites materials

WOS: 000313854200062The aim of this study is to examine the use of Ferula communis fibers as potential reinforcement in polymer composites. The fibers are extracted from the F. communis plant which grows in Selcuk, Izmir in western Turkey. The chemical composition of ferula fibers in terms of cellulose, lignin, and ash contents was determined. Surface functional groups of ferula fibers were obtained by fourier transform infrared and Xray photoelectron spectroscopy. Crystallinity index and crystallite size were determined by X-ray diffraction analysis. The morphology of ferula fibers was investigated through scanning electron microscopy, the thermal behavior through thermogravimetric and differential scanning calorimetry analyses. The real density of ferula fibers was measured by means of Archimedes method with ethanol. The mechanical properties of F. communis were measured through single fiber tensile tests. The interfacial shear strength (IFSS) in a polyester matrix has been estimated from the pull-out test. Crown Copyright (C) 2012 Published by Elsevier Ltd. All rights reserved.Natural Science Foundation of Dokuz Eylul University under BAPDokuz Eylul University [2008145]The Authors sincerely acknowledge Natural Science Foundation of Dokuz Eylul University under BAP Grant No. 2008145 due to differential scanning calorimetry analysis. Also we thank Prof. Dr. Mithat Yuksel, Burhan SIMSIR and Selman Gulsen for their contributions to the study