Thermal characterization of composites of polyamide-6 and polypropylene involving boron compounds via direct pyrolysis mass spectrometry

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Tezin Türü: Doktora

Tezin Yürütüldüğü Kurum: Orta Doğu Teknik Üniversitesi, Fen Edebiyat Fakültesi, Kimya Bölümü, Türkiye

Tezin Onay Tarihi: 2013

Öğrenci: GÜLLÜ CEYDA İŞBAŞAR AFACAN

Eş Danışman: JALE HACALOĞLU, ÜLKÜ YILMAZER

Özet:

In this work, the effects of addition of boron compounds, boron phosphate (BPO4), zinc borate (ZnB), borosilicate (BSi) and lanthanum borate (LaB), on thermal degradation characteristics of composites of polyamide 6 (PA6) and polypropylene (PP) are analyzed via Direct Pyrolysis Mass Spectrometry (DP-MS) technique. The composites of PA6 involve nitrogen containing flame retardants, melamine (Me) or melamine cyanurate (MC); or phosphorus containing flame retardant, aluminum diethylphosphinate (AlPi), with or without organically modified clay. Composites of PP involve intumescent flame retardants (IFR) with or without maleic anhydride grafted polypropylene (PP-g-MA) and organically modified clay. The presence of Me or MC does not affect thermal stability of PA6, but due to the strong interactions between Me, MC or isocyanic acid and PA6, generation of new fragments occurs and loss of Me or MC is shifted to high temperatures. Presence of boron compounds results in significant changes in loss of Me and MC and thermal degradation products of the PA6. The presence of AlPi decreases thermal stability of PA6 noticeably. Addition of boron compounds or organically modified clay, improves the thermal stability of PA6/AlPi composite, most probably due to the weakening of the interactions between AlPi and PA6. Addition of boron containing compounds to PP involving IFR, improves the thermal stability of PP; yet, no significant differences in the thermal degradation pathways of PP are observed. Moreover, decrease in the relative intensities of PP based fragments with high mass and in those of both pentaerythritol (PER) and ammonium polyphosphate (APP) based fragments are recorded. Upon addition of Cloisite 15A, the thermal stability of PP is decreased. Inclusion of IFR to this composite improves the thermal stability. Inclusion of all boron compounds (especially ZnB) affects the thermal stability of the composite.