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Article Citation - WoS: 64Citation - Scopus: 74Production and Characterization of Poly (lactic Acid)-Based Biocomposites Filled With Basalt Fiber and Flax Fiber Hybrid(Sage Publications Ltd, 2020) Eselini, Najah; Tirkes, Seha; Akar, Alinda Oyku; Tayfun, UmitPoly (lactic acid) (PLA)-based biocomposites containing flax fiber (FF) and basalt fiber (BF) both separately and together were prepared by melt blending method at the total constant ratio of 30 wt%. Mechanical properties, thermo-mechanical characteristics, thermal stability, flow behaviors, water uptake, and morphology of composites were investigated by tensile, hardness and impact tests, dynamic mechanical analysis (DMA), thermal gravimetric analysis, melt flow index (MFI) test, water absorption, and scanning electron microscopy, respectively. Mechanical test results show that tensile strength, elongation, elastic modulus, and impact strength are extended up to higher values with increase in BF content in hybrid composites. Conversely, the presence of FF displays a negative effect in which these values drop down drastically as the FF concentration increases. On the other hand, slightly higher hardness values are obtained by the addition of FF at higher loadings. DMA analysis reveals that BF inclusion leads glass transition temperature of PLA to one point higher, but hybrid and FF containing composites shift that temperature to lower values. Storage moduli of composites are enhanced with the increase in BF concentration and remarkable decreases are observed for FF-filled composites. Hybrid composites exhibit average MFI values between PLA/FF and PLA/BF composites.Article Citation - WoS: 14Citation - Scopus: 17Hybrid Nanocomposites of Elastomeric Polyurethane Containing Halloysite Nanotubes and Poss Nanoparticles: Tensile, Hardness, Damping and Abrasion Performance(Cambridge Univ Press, 2020) Mohamed, Salma Taher; Tirkes, Seha; Akar, Alinda Oyku; Tayfun, UmitThermoplastic polyurethane (TPU) matrix was reinforced with polyhedral oligomeric silsesquioxane (POSS) and halloysite nanotubes (HNT), both separately and combined. Composite samples were fabricated using a melt-compounding method. Characterization of the composites obtained was performed via tensile and hardness tests, melt-flow index measurements (MFI), abrasion tests, dynamic mechanical analysis (DMA) and scanning electron microscopy (SEM) to investigate the mechanical performance, flow behaviour, tribological characteristics, thermo-mechanical response and morphological properties. The greatest tensile strength value was obtained for the smallest HNT content. Further addition of HNT resulted in agglomerations for both POSS and HNT particles. The shore hardness of TPU was enhanced by filler inclusions. The TPU/POSS composites displayed significant improvement in terms of abrasion resistance compared to TPU at lower loading levels. The DMA study showed that composites containing 0.5% POSS and 1.0% HNT displayed the greatest storage modulus. The glass-transition temperature of TPU shifted to smaller values with the addition of both nanoparticles. The HNT inclusions increased the MFI value of TPU because of their large aspect ratio. Homogeneous mixing of nanoparticles in the TPU matrix was confirmed by a SEM study of the composites. Their dispersion decreased as the concentrations of POSS and HNT increased. An adjuvant effect of POSS with HNT was achieved in their hybrid composites.Article Citation - WoS: 31Citation - Scopus: 34Mechanical, Thermo-Mechanical and Morphological Characterization of Abs Based Composites Loaded With Perlite Mineral(Iop Publishing Ltd, 2020) Alghadi, Aiah Mohamed; Tirkes, Seha; Tayfun, UmitAcrylonitrile-butadiene-styrene (ABS) copolymer was filled with perlite mineral (PER) at four different loading level of 2.5%, 5%, 10% and 15%. ABS/PER composites were produced using lab-scale micro-compounder followed by injection molding process. Mechanical, thermo-mechanical, melt-flow and morphological properties of composites were reported by tensile and impact tests, dynamic mechanical analysis (DMA), melt flow index (MFI) test and scanning electron microscopy (SEM), respectively. Mechanical characterizations revealed that tensile strength, elongation and Youngs? modulus of ABS were improved by PER inclusions. However, impact strength of ABS reduced with increase of PER concentration. Glass transition temperature of ABS displayed increasing trend for %5 concentration of PER. MFI test implied that PER addition caused slight decreasing for MFI value of unfilled ABS. Homogeneous dispersion of PER particles into ABS matrix for their lower loading level was obtained from SEM micrographs of composites. According to findings, 5% PER containing sample exhibited the best performance and it was remarked as the most suitable candidate among fabricated ABS based composites.
