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    Novel and eco-friendly hydrophobic treatment of cotton and polyester fabrics based-on octavinyl and aminopropylisobutyl polyhedral oligomeric
    (Elsevier Sci Ltd, 2023) Akbasak, Tughan; Kodal, Mehmet; Mert, Olcay; Ozkoc, Gueralp
    The hydrophobicity of cotton and polyester fabrics plays a significant role in various industrial applications. Anchoring hydrophobic chemicals onto the fabric surface is one of the major strategies. Fluorinated chemicals are widely employed to construct hydrophobic surfaces. However, alternative hydrophobic coatings are urgently sought by researchers due to the potential risks and hazards of fluorinated chemicals. Polyhedral oligomeric silsesquioxanes (POSS) are one of the most potential alternatives as they increase the roughness and lower the surface energy through chemical enhancement of the surface. In this work, hydrophobic cotton and polyester surfaces were fabricated anchoring Octavinyl POSS (OL-POSS) and Aminopropylisobutyl POSS (AM-POSS) onto the surface via one-step dip-coating technique. To enhance the surface roughness and the hydrophobicity, Ul-traviolet (UV) radiation was employed with Benzoyl Peroxide (BPO) initiator. Water contact angle (WCA) of both fabrics increased from 0 degrees to 136 degrees using 5% POSS coatings with initiator and UV present. Water absorption duration (WAD) also increased from several seconds up to 310 min. Furthermore, 5% POSS modified fabrics gave similar or better WAD values when compared to coatings treated with fluorinated chemicals. The findings confirmed that OL-POSS and AM-POSS coatings are eligible environmentally friendly candidates for the replacement of fluorinated chemicals.
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    Unlocking the Potential Use of Reactive POSS as a Coagent for EPDM/PP-Based TPV
    (Mdpi, 2023) cakir, Nazli Yazici; Inan, Oezgenur; Ergun, Merve; Kodal, Mehmet; Ozkoc, Gueralp
    Thermoplastic vulcanizates (TPVs) are multifunctional materials consisting of two or more phases with solid elastomeric properties at room temperatures and fluid-like properties above their melting point. They are produced through a reactive blending process known as dynamic vulcanization. The most widely produced TPV type is ethylene propylene diene monomer/polypropylene (EPDM/PP), which is the focus of this study. The peroxides are mainly selected to be used in crosslinking of EPDM/PP-based TPV. However, they still have some disadvantages, such as the side reactions resulting in the beta chain scission of the PP phase and undesired disproportionation reactions. To eliminate these disadvantages, coagents are used. In this study, for the first time, the use of vinyl functionalized polyhedral oligomeric silsesquioxane (OV-POSS) nanoparticles was investigated as a potential coagent in EPDM/PP-based TPV production via peroxide-initiated dynamic vulcanization. The properties of the TPVs having POSS were compared with the conventional TPVs containing conventional coagents, such as triallyl cyanurate (TAC). POSS content and EPDM/PP ratio were investigated as the material parameters. Mechanical properties of EPDM/PP TPVs exhibited higher values in the presence of OV-POSS, which resulted from the active participation of OV-POSS into the three-dimensional network structure of EPDM/PP during dynamic vulcanization.