Sentetik Grafit Dolgulu Polipropilen Kompozitlerin Reolojik Özelliklerinin Belirlenmesi

Konferans Bildirisi-- İstanbul Teknik Üniversitesi, Teorik ve Uygulamalı Mekanik Türk Milli Komitesi, 2017Conference Paper -- İstanbul Technical University, Theoretical and Applied Mechanical Turkish National Committee, 2017Sentetik grafit (SG) polimerlerin elektriksel ve termal iletkenliklerini iyileştirmek için sıklıkla kullanılır. Polimerin içine SG yüklenmesi polimerin reolojik özelliklerini de değiştirir. Bu çalışmada amaç polipropilen kopolimerin (PPc) içerisine yüklenen SG’nin reolojik özelliklerini nasıl değiştirdiğini ortaya koymaktır. SG yüklenmiş PPc kompozit pelletler Leistritz Extruder Corporation ZSE 27 model çift vidalı ekstrüder kullanarak üretilmiştir. SG yüklenmesi polimer eriyiğinin içine ekstrüderin yan besleyicisinden yapılmıştır. PPc ve SG yüklenmiş PPc kompozitlerin reolojik özellikleri Göttferd, Rheograph 20 model kapiler reometre kullanarak incelenmiştir. PPc ve üç farklı oranda SG yüklemiş PPc kompozitlerin gözlemlenen ve düzeltilmiş verileri kullanarak reolojik özellikler incelenmiştir. Görünür viskozite ve kayma gerilmesi değerlerine ek olarak, PPc ve SG yüklemiş kompozitlerin normal gerilim fark değerleride bulunmuştur. Elde edilen sonuçlar Carreau-Winter modeli tarafından değerlendirilmiştir. SG yüklenmesinin PPc nin sıfır-kayma viskozitesini arttırdığı bulunmuştur. %10 ve %30 SG yüklenmesi sıfır-kayma viskozitesini çok fazla arttırmaz iken %50 yüklenmesi ise ciddi oranda arttırmıştır.Synthetic graphite(SG) is frequently used to improve electrical conductivity and thermal conductivity of polymers. SG filling into polymers changes the rheological properties of polymers. In this study, the effect of SG filling into polypropylene copolymer (PPc) on the rheological properties of PPc was investigated. SG filled PPc composite pellets were prepared by using twin screw extruder (Leistritz Extruder Corporation Model ZSE 27). SG was fed into polymer melt from the side feeder. Rheological properties of PPc and SG filled PPc composite pellets were determined by using a capillary rheometer (Göttferd, Rheograph 20). Apperent and corrected data were used for investigation of rheological properties of PPc and SG filled PPc composites. In addition to apperent viscosity and shear stress, normal stress difference values for PPc and SG filled PPc composites were also obtained. The results were evaluated by Carreau-Winter model. SG filling into PPc increased zero-shear viscosity value of PPc. 10 and 30 wt% of SG has not led to considerable increase in zero-shear viscosity of PPc. However 50 wt%SG filling ito PPc has largely increased zero-shear viscosity

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

Carbon Nanotube-, Boron Nitride-, and Graphite-Filled Polyketone Composites for Thermal Energy Management

In order to improve the thermal conductivity of 30 wt % synthetic graphite (SG)-filled polyketones (POKs), conductive fillers such as multiwall carbon nanotubes (CNTs) and hexagonal boron nitride (BN) were used in this study. Individual and synergistic effects of CNTs and BN on 30 wt % synthetic graphite-filled POK on thermal conductivity were investigated. 1, 2, and 3 wt % CNT loading enhanced the in-plane and through-plane thermal conductivities of POK-30SG by 42, 82, and 124% and 42, 94, and 273%, respectively. 1, 2, and 3 wt % BN loadings enhanced the in-plane thermal conductivity of POK-30SG by 25, 69, and 107% and through-plane thermal conductivity of POK-30SG by 92, 135, and 325%. It was observed that while CNT shows more efficient in-plane thermal conductivity than BN, BN shows more efficient through-plane thermal conductivity. The electrical conductivity value of POK-30SG-1.5BN-1.5CNT was obtained to be 1.0 × 10-5 S/cm, the value of which is higher than that of POK-30SG-1CNT and lower than that of POK-30SG-2CNT. While BN loading led to a higher heat deflection temperature (HDT) than CNT loading, the hybrid fillers of BNT and CNT led to the highest HDT value. Moreover, BN loading led to higher flexural strength and Izod-notched impact strength values than CNT loading