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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.

Syndiotactic polystyrene (SPS) has attracted considerable attention recently due to its high melting temperature, low cost, and relatively low density value. The aim of the study is to reveal whether a blend of PPS and SPS (PPS-SPS) can be used instead of PPS for high thermal stability, high mechanical performance, and high thermal conductive material applications. For this aim, poly(phenylene sulfide)/syndiotactic polystyrene-based carbon-loaded composite materials were prepared using a twin screw extruder. Two carbon based materials, carbon fiber (CF) and synthetic graphite (SG), were used to improve the mechanical properties and thermal conductivity of the PPS-SPS blends. Through-plane conductivity values of PPS-30SG-10CF and PPS-SPS-30SG-10CF were obtained to be 13.67 and 12.92 W/mK, with densities of 1.55 and 1.50 g/cm3, respectively. It was demonstrated that PPS-SPS blend-based carbon-loaded composites have great potential to be used in thermal management applications with the advantages of relatively low cost and lightweight compared to PPS-based composites., Scientific and Technological Research Council of Turkey [117M088]; R & D Center of IMS Polymers, The authors are grateful for the funding from the Scientific and Technological Research Council of Turkey (Project no: 117M088) and the R & D Center of IMS Polymers.

In this study, halogen-free flame retardants and metal synergist materials were used to enhance the flammability of PA6. PA6-based composites including various fractions of additives were manufactured using a twin-screw extruder and an injection molding machine. Mechanical, thermal, physical, morphological, and flame retardant properties were investigated with several characterization methods. The study aims to meet R22 requirements based on the EN45545 standard for fire protection of railway vehicles, according to which limiting oxygen index (LOI), smoke density, and conventional index of toxicity (CIT) values under HL3 hazard levels have to be min 32%, max 300, and max 1.5, respectively. 15FR-2MH, 15FR-5MH, 15FR-1MH-1ZB, 15FR-1MH-1BOH, and 15FR-1MH-1SIL composites exhibited both the required smoke density, CIT, and LOI values for R22. It can be said that hybrid synergists provide all requirements according to the R22-EN45545 standard . Instead of using 15FR-2MH, 15FR-1MH-1BOH led to a lower smoke density value for PA6., Izmir Egitim Saglik Sanayi Yatirim A.S (IMS Polymers) RD Center [MG014], The authors gratefully acknowledge the financial support given by the Izmir Egitim Saglik Sanayi Yatirim A.S (IMS Polymers) R&D Center (project no: MG014, project title: Development of Halogen-Free Polyamide 6-Based Composite Materials with High LOI).

7th International Advances in Applied Physics and Materials Science Congress and Exhibition (APMAS) -- APR 22-26, 2017 -- Fethiye, TURKEY, WOS: 000451281600052, Over the last decades, automotive industries have investigated a variety of technological developments and design strategies. The reduction of vehicle weight has been proved to be a particularly effective way to meet automobile performance requirements in the areas of fuel economy and emissions. One major option in the vehicle weight reduction strategy is the use of lightweight materials, namely the carbon fiber reinforced polymers. However, poor adhesion between carbon fibers and polymer matrix could be an important issue for carbon fiber reinforced polymers. In this study, in order to increase interfacial bonding between carbon fibers and the polymer matrix, maleic anhydride grafted polypropylene at different weight contents was used as a compatibilizer for better polymer/fiber interpenetration. Recycled chopped carbon fiber reinforced polypropylene composites with maleic anhydride grafted polypropylene were prepared with high speed thermo kinetic mixing and hot press molding techniques. Thermal properties of the composites were studied by thermal gravimetric analysis and differential scanning calorimety. Morphology of the composites was observed by scanning electron microscopy. The tensile properties of these composites were investigated. Tensile strength values of recycled chopped carbon fiber reinforced polypropylene based composites increased with increasing compatibilizer content.

Polypropylene (PP) was filled with synthetic graphite (SG) and graphene nanoplatelets (G) at different weight fractions. Composites were prepared by the melt mixing process by using a co-rotating twin screw extruder. Mechanical tests were carried out to determine tensile and flexural properties of composites. Dynamic Mechanical Analysis of composites was performed to determine their thermo-mechanical properties, such as storage modulus and loss modulus. Scanning Electron Microscopy was used to observe the fracture surfaces of the composites after tensile tests. The effect of SG and G on thermal properties such as melting and crystallization temperature, thermal conductivity, thermal stability, and coefficient of thermal expansion of PP was investigated. Tensile strength and flexural strength of PP increased with the addition of 10 wt% SG. The highest thermal conductivity achieved in this study at 50 wt% SG and 3 wt% G loading was 4.6 W/mK. POLYM. COMPOS., 40:277-287, 2019. (c) 2018 Society of Plastics Engineers

Seki, Yoldas/0000-0002-2225-1236; ATAGUR, Metehan/0000-0002-1916-457X, WOS:000448083600027, Recycled carbon fiber reinforced polypropylene (PP) composites were fabricated by using high speed thermo-kinetic mixer. The effect of recycled carbon fiber on the morphological, chemical, physical, thermal, and mechanical properties of PP composites was investigated. The results indicate that the tensile and flexural strength of PP increase with addition of recycled carbon fiber up to 20 wt%. When 40 wt% recycled carbon fiber was added into PP, the tensile and flexural moduli were increased by about 177 and 359%, respectively. The coefficient of thermal expansion was found to be decreased by increasing recycled carbon fiber weight fraction. The addition of low weight fraction of recycled carbon fibers (up to 5 wt%) increased the nucleation process on PP crystallization. POLYM. COMPOS., 39:3656-3665, 2018. (c) 2017 Society of Plastics Engineers

In this study, multilayer graphene (Gr)-reinforced cellulose composites were synthesized by using 1-ethyl-3-methylimidazolium diethylphosphonate ionic liquid. The composites were fabricated via dissolving the cellulose in 1-ethyl-3-methylimidazolium diethylphosphonate and Gr loading at different ratios (0.2, 0.4, and 0.6 wt.%). Both sides of the composites were coated with gold leaf to generate electrodes. The effect of Gr loading on chemical functional groups, crystallographic properties, thermal stability, and morphological and mechanical properties of cellulose film was investigated by Fourier transform infrared spectroscopy, X-ray diffraction, thermogravimetric analysis, scanning electron microscopy, and tensile test, respectively. Electromechanical behavior of the cellulose composite films reinforced with Gr (0.2, 0.4, and 0.6 wt.%) was investigated under DC excitation voltages of 1, 3, 5 and 7 V. Gr loading of 0.2 wt.% increased maximum tip displacement by 400% when the actuator is excited with 3 V.

The effect of gold electrode thickness (10, 27, 45, 67 and 80 nm) on the electromechanical performance of Nafion-based Ionic Polymer Metal Composite (IPMC) actuators was investigated in this study. The mechanical, morphological, electrical properties and electroactive behaviors of IPMC under direct current voltage (DC) and alternating voltage (AC) were examined. The tip displacement and maximum blocking force of actuators under various electrical stimulations were measured. In order to define transient response characteristics and quasi-steady state value of the actuators, DC excitations of 1, 3, 5, 7 and 9 V were used. Besides, to define bandwidth of the actuator samples, square wave excitation with magnitudes of 3, 5, and 7 V and frequencies of 0.1, 0.25, 0.5, 1, and 2 Hz were applied to actuator samples. The actuator having a gold electrode thickness of 45 nm produced maximum tip displacement among all actuators for all excitation DC voltages. In the square wave experiments, the higher cutoff frequencies were observed for the actuators with 27 and 45 nm electrode thicknesses. The blocking force of IPMC increased with increasing gold electrode thickness from 10 nm to 45 nm and decreased with increasing gold electrode thickness from 45 nm to 80 nm.

A detailed characterization of Graphene (Gr) loaded chitosan films was conducted in this study. Thermal characterization of Gr loaded CS films was made by using thermogravimetric analysis and thermal conductivity measurement. 1, 2, and 3 wt% loading of Gr into CS increased the thermal conductivity of CS by 25, 258 and 244%, respectively. The effect of Gr loading into CS on electrical resistivity properties of CS was determined by surface resistivity measurements. 1 wt% loading of Gr decreased the surface resistivity of CS film from 4.7 x 10(5) Omega/sq to 4.4 x 10(3) Omega/sq. Viscoelastic properties of CS-Gr composite film samples were analyzed by using dynamic mechanical analysis. Mechanical, morphological, crystallographic properties of composite films were determined by tensile tests, scanning electron microscopy (SEM) observations, and X-ray diffraction analyses, respectively. The storage modulus of CS was increased by 32% with 1 wt% Gr loading into CS. With the loading of 1 wt% of Gr, tensile strength and Young's modulus of CS film increased by 128%, and 52%, respectively. The hydrophilicity of the CS and CS-Gr composites films was examined by contact angle measurements. (C) 2016 Elsevier Ltd. All rights reserved.

7th International Advances in Applied Physics and Materials Science Congress and Exhibition (APMAS) -- APR 22-26, 2017 -- Fethiye, TURKEY, WOS: 000451281600075, High density polyethylene (HDPE) has been used extensively in many sectors of the industry. The main reason for the frequent use of HDPE is its low cost, easy processing, and high performance. These sectors include household and garden products, packaging etc. In order to reduce the production cost of plastic products and to improve plastic's moldability and stability, one or more minerals are usually filled into the thermoplastics. The minerals commonly used as fillers in plastic molding compounds include calcium carbonate, talc, silica, wollastonite, clay, mica, glass beads, and alumina trihydrate. In this paper, diatomite (DA) filled HDPE composites were prepared with gelimat mixer and hot press molding technique. Thermal properties of the composites were studied by thermogravimetric analysis and dynamic mechanical analysis. The mechanical properties of the composites were determined by using universal testing machine. Morphology of the composites was investigated by scanning electron microscopy. With the addition of DA into HDPE, significant change in tensile and flexural strengths of HDPE was not observed. The loss and storage moduli increased with increasing weight fraction of DA.

7th International Advances in Applied Physics and Materials Science Congress and Exhibition (APMAS) -- APR 22-26, 2017 -- Fethiye, TURKEY, WOS: 000451281600053, The aim of this study is to develop composites with high thermal conductivity by employing the thermophysical properties of aluminum nitride (AlN), hexagonal boron nitride (hBN), and synthetic graphite (SG). AlN, hBN, and SG filled polyamide 6 (PA) composites were prepared using a co-rotating twin-screw extruder and injection molding. Changes in thermal, mechanical, and electrical properties of the composites were investigated. The highest in-plane and through-plane thermal conductivity values were obtained with 50 wt.% SG and 50 wt.% AlN loadings, respectively. Mechanical strength of PA decreased for all filler loadings. Electrical conductivity results showed that AlN and hBN filled PA composites behave as electrical insulators. On the contrary, SG loading led to electrically conductive PA composites.

In this study, graphene nanoplatelets (0.10, 0.25, and 0.50 wt.%) were loaded into cellulose matrix to improve electroactive performance of cellulose-based composite actuators. Firstly, cellulosic films were produced by dissolving microcrystalline cellulose in 1-butyl-3-methylimidazolium chloride. Afterwards, graphene loaded cellulosic films were fabricated and gold leaf was coated on both surfaces of graphene loaded cellulose-based films. The changes in crystallographic properties and chemical functional groups of cellulose were investigated by X-ray diffraction and Fourier transform infrared analyses, respectively. Besides, thermal stability, electrical conductivity, and morphological properties of the films were examined by thermogravimetric analysis, electrical conductivity measurement, and scanning electron microscopy, respectively. The tensile strength and the Young's modulus of the films and actuators were also determined by tensile tests. The electroactive characteristics were analyzed under DC excitation voltages of 3 V, 5 V and 7 V. The time responses were evaluated via proposed experimental data based model. The performances of the actuators were compared in terms of maximum tip displacement, minimum tip displacement and time constant. (C) 2014 Elsevier Ltd. All rights reserved.

Vine stem is an agricultural side product and has limited economic value. Alternative uses of such agricultural powder into value-added products such as thermoplastic composites can provide remarkable environmental and economic benefits. Vine stem filler may be used as a potential reinforcement in polymeric materials. In this study, vine stem reinforced high density polyethylene (HDPE) composite materials were manufactured and characterized. Agricultural waste of vine stem was collected from Manisa region, Turkey. Vine stem was ground in a grinder and thereby turning into the powder form. Composites were obtained using twin screw extruder by adding different amounts of vine stem powder (5,10 and 20% wt.) into HDPE. Mechanical, thermal, water absorption and crystallographic properties of waste vine stem reinforced HDPE composites were investigated. HDPE containing 10% waste vine stern exhibited the highest tensile strength and flexural strength. Vine stem powder addition into HDPE delayed the thermal decomposition of HDPE. DMA analyses showed that the storage modulus values of reinforced HDPE are higher than neat HDPE throughout the whole temperature scale. (C) 2016 Elsevier Ltd. All rights reserved.

Woven roving jute fiber-reinforced unsaturated polyester composites were subjected to water absorption tests in order to study the effects of water ageing on the mechanical properties. Composite specimens were immersed in distilled water and salt water up to 2736 h. The water absorption of specimens reached to an equilibrium level after an immersion time of 300 h. It was observed that tensile, flexural, and interlaminar shear strengths (ILSSs) of jute/polyester composites decreased depending on the immersion time. The ILSS values of the composites were reduced by more than 53% for both the distilled water and the salt water after an immersion time of 2736 h.

© 2015, Springer Science+Business Media Dordrecht.Electroactive behavior of carboxymethylcellulose (CMC)-based actuators was investigated in this study. CMC-based films were firstly fabricated by using 1-butyl-3-methylimidazolium bromide. Characterization studies of the CMC films were conducted by using Fourier transform infrared, X-ray diffraction analysis, thermogravimetric analysis, scanning electron microscopy, and tensile testing. CMC-based actuator films were produced by gold coating on both surfaces of CMC-based films. Polyethylene glycol (PEG) at different loadings (1, 1.5 and 2 g) was used to improve electroactive behavior of CMC based actuators. Maximum tip displacements were obtained under DC excitation voltages of 1, 3, 5 and 7 V. CMC based actuator loaded with 1.5 g PEG exhibited the largest tip displacement among other actuators for each excitation voltage. The PEG loading did not lead to considerable differences in tensile strength of CMC-based films. However, Young’s modulus decreased with PEG loading.

In this article, the effects of graphene loading (0.1, 0.2, 0.3 wt%) on both the electromechanical and mechanical properties of carboxymethylcellulose (CMC)-based actuators were investigated. CMC-based graphene-loaded actuators were prepared by using 1-butyl-3-methylimidazolium bromide. The synthesized graphene-loaded actuators were characterized by Fourier transform infrared, X-ray diffraction analysis, thermogravimetric analysis, scanning electron microscopy, and tensile tests. Electromechanical properties of the actuators were obtained under DC excitation voltages of 1, 3, 5, and 7 V with a laser displacement sensor. According to the obtained results, the ultimate tensile strength of CMC-based actuators containing 0.3 wt% graphene was higher than that of unloaded actuators by approximately 72.8 %. In addition, the Young’s modulus value of the graphene-loaded actuators increased continuously with increasing graphene content. Under a DC excitation voltage of 5 V, the maximum tip displacement of 0.2 wt% graphene-loaded actuators increased by about 15 % compared to unloaded actuators.

The effects of the PWM excitation signal parameters, such as frequency and magnitude, on the Nafion-based ionic polymer metal composite (IPMC) actuator response were found out. The first set of experiments was designed to observe the actuator response when the actuators were biased with constant DC voltages. These experimental results were exploited to build an experimental data based dynamic model. The model and these results were also used as references to evaluate the experimental results in the proceeding experiments. The second set of experiments was designed to observe the actuator response when the DC square wave signals at different frequencies (0 to 1000 Hz) were applied. The third set of experiments was designed to observe the actuator response when the PWM signals at different magnitudes (6, 8 and 10 V) were applied. It is observed that back relaxation reduces with increasing frequency, but after a certain frequency value, it remains approximately constant. It is seen that the input output relationship of the actuators are linear only for a range of PWM signal magnitudes. The observations in both the PWM frequency and the magnitude experiments indicated that the performance of the Nafion-based IPMC actuator could be improved by selecting a magnitude of PWM signals between 6-8 Volts and by selecting a frequency between 400-1000 Hz.