Chemical Engineering / Kimya Mühendisliği
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Book Part Citation - Scopus: 2Influence of Filler Surface Modification on the Properties of Pp Composites(Wiley, 2015) Balköse, DevrimThis chapter reviews the fillers have been grouped as silica, glass, silicates, magnesium hydroxide and eggshell, cellulose and carbon, and their surface modification techniques. It explains the effects of the surface modification of fillers on the properties of composite materials having polypropylene as the matrix. The surface modification of fillers affects the properties of the polypropylene matrix composites in different aspects depending on the types of the filler and the modifications. The polypropylene phase was also functionalized by treating PP with MA or ammines. The properties most affected are the tensile strength, Young modulus, and elongation at break of the composites. If crosslinking occurs between the filler and functionalized PP, the tensile strength increases and elongation at break decreases owing to decrease in mobility. PP crystallite formation at the interface also increases the adhesion between filler and matrix. © 2015 Wiley-VCH Verlag GmbH & Co. KGaA. All rights reserved.Article Citation - WoS: 43Citation - Scopus: 47Bioactive Diatomite and Poss Silica Cage Reinforced Chitosan/Na-carboxymethyl Cellulose Polyelectrolyte Scaffolds for Hard Tissue Regeneration(Elsevier, 2019) Tamburacı, Sedef; Kimna, Ceren; Tıhmınlıoğlu, FundaRecently, natural polymers are reinforced with silica particles for hard tissue engineering applications to induce bone regeneration. In this study, as two novel bioactive agents, effects of diatomite and polyhedral oligomeric silsesquioxanes (POSS) on chitosan (CS)/Na-carboxymethylcellulose (Na-CMC) polymer blend scaffolds are examined. In addition, the effect of silica reinforcements was compared with Si-substituted nano-hydroxyapatite (Si-Hap) particles. The morphology, physical and chemical structures of the scaffolds were characterized with SEM, liquid displacement, FT-IR, mechanical analysis, swelling and degradation studies. The particle size and the crystal structure of diatomite, POSS and Si-Hap particles were determined with DLS and XRD analyses. In vitro studies were performed to figure out the cytotoxicity, proliferation, ALP activity, osteocalcin production and biomineralization to demonstrate the promising use of natural silica particles in bone regeneration. Freeze-dried scaffolds showed 190-307 mu m pore size range and 61-70% porosity. Both inorganic reinforcements increased the mechanical strength, enhanced the water uptake capacity and fastened the degradation rate. The nanocomposite scaffolds did not show any cytotoxic effect and enhanced the surface mineralization in osteogenic medium. Thus, diatomite and POSS cage structures can be potential reinforcements for nanocomposite design in hard tissue engineering applications.