Effects of nanoparticles on thermal characteristics of polyamide-6, polylactic acid and polystyrene involving various flame retardants

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Tezin Türü: Doktora

Tezin Yürütüldüğü Kurum: Orta Doğu Teknik Üniversitesi, Mühendislik Fakültesi, Metalurji ve Malzeme Mühendisliği Bölümü, Türkiye

Tezin Onay Tarihi: 2013

Öğrenci: HATİCE KAYA

Eş Danışman: CEVDET KAYNAK, JALE HACALOĞLU

Özet:

In this work, the effects of addition of nanoparticles halloysite, (HNT), organically modified montmorillonites (MMT10A, MMT25A and MMT30B) and SiO2 on thermal degradation characteristics of polyamide 6 (PA6), polylactide (PLA) and polystyrenes (PS and HIPS) involving flame retardants are investigated. The composites of PA6 and PLA involve phosphorus containing flame retardant, aluminium diethylphosphinate (AlPi). Composites HIPS involve mineral flame retardant, aluminium hydroxide and those of PS involve halogenated flame retardant, brominated epoxy (BE). Addition of MMT25A does not affec+ thermal stability of PA6. On the other hand, thermal stability of PA6 decreases in the presence of HNT, and increases in the presence of MMT30B. Upon incorporation of AlPi thermal stability of PA6 decreases noticeably. Addition of nanoparticles to flame retarded PA6 affects both thermal stability and product patterns. In the presence of AlPi, thermal stability of PLA is decreased due to the attack of phosphinate groups to carbonyl groups. Upon addition of MMT30B to PLA-AlPi, thermal stability of the composite is increased slightly. In addition, trans-esterification reactions between PLA and the organic modifier of the nanoclay are noted. Presence of SiO2 affects mainly product patterns of AlPi, whereas, in the presence of HNT, the interactions between PLA and AlPi are hindered, and product patterns resemble to those of the pure forms. Products involving head-to-head linkages, double and triple bonds are generated during the pyrolysis of HIPS in the presence of MMT10A. The addition of aluminium hydroxide enhances the effects of the clay. Reactions between BE and PS, and upon addition of Sb2O3, reactions between BE and Sb2O3 and between the products generated and PS are noticed. Addition of MMT10A hinders the interactions between BE and PS. On the other hand, the reactions of Sb2O3 with bromines are increased in the presence of MMT10A.