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  • Küçük Resim
    Öğe
    Effects of Microcrystalline Cellulose on Some Performance Properties Chitosan Aerogels
    (2021) Özen, Ertan; Yıldırım, Nadir; Dalkılıç, Berk; Ergün, Mehmet E.
    The aim of this research was to investigate the effect of the microcrystalline cellulose reinforcement on some physical, mechanical, thermal, and morphological properties of the chitosan aerogels. The bio-based chitosan aerogels were produced using chitosan as a matrix and the microcrystalline cellulose as a reinforce material through the freeze-drying method. The aerogel suspensions were prepared in five different ratios to investigate the effect of microcrystalline cellulose content. The density, porosity, thermogravimetric analysis, and compressive resistance tests were conducted according to relevant standards. Morphological properties were investigated using a scanning electron microscope. The introduction of microcrystalline cellulose significantly improved the compressive resistance, thermal properties (T-onset and T-%50) of the chitosan aerogels. The optimum performance properties determined as 0,12 MPa for compressive resistance, 0,27 MPa for compressive modulus, 292,45 degrees C for T-onset and 365 degrees C for T-%50. According to scanning electron microscope images, aerogels showed microporous structure as expected. As a result, the bio-based chitosan aerogels reinforced with microcrystalline cellulose were successfully manufactured. The mechanical and thermal properties including compressive resistance, compressive modulus, T-onset and T-%50 of chitosan-microcrystalline cellulose aerogels found promising.
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    Öğe
    Manufacture of wood fiber reinforced polyvinyl acetate rigid foams
    (2020) Ergün, Mehmet Emin; Özen, Ertan; Yildirim, Nadir; Dalkılıç, Berk
    In this work, rigid foams designed and manufactured using the freezedrying technique were made from polyvinyl acetate (PVAc), bleachedkraft pulp and unbleached kraft pulp. The rigid foams designed asan environmentally-friendly product with no pentane or hydrochlorofluorocarbon included in the manufacturing process. The PVAcbased foams were reinforced with different kraft pulp contents. Theirperformance properties such as compressive and flexural strength,physical and morphological properties were investigated according torelevant standards. The foam densities ranged from 0,017 g/cm3 with%17,65 coefficient of variation (CV) to 0,137 g/cm3 with %2,33 CV.The compression resistance was found between 0,001 N/mm2 with%50,00 CV and 0,03 N/mm2 with %5,98 CV. The flexural resistancewas found between 0,005 N/mm2 with %20,00 CV and 0,11 N/mm2with %6,06 CV. Optimum properties were observed at B-4 (PVAc/Bleached Kraft pulp 1/0.8). Bleached kraft pulp reinforcement gavebetter results on performance characteristics of foam materials compared to unbleached kraft pulp reinforcement. Overall test resultsshowed that the PVAc based rigid foams have promising results.