In this diploma thesis, the effect of incorporating the organophosphorus compound 6, 6'-(1-
phenylethane-1,2-diyl)bis(dibenzo[c,e][1,2]-oxaphosphinine-6-oxide) (PHED) into the
polymer matrix of a commercial fibre-forming PA6 (Aquamide 24401) during the meltspinning process of a PA6/PHED filament yarn was investigated in terms of its thermooxidative stability and physical-mechanical properties. It is evident from the literature that the
in situ incorporation of the flame retardant PHED additive during the polymerization process
results in high flame retardant efficiency for the PA6/PHED-is textile filament. Since the use
of flame retardant composites, produced by melt-compounding is a common approach used in
the industry, the aim of this thesis was to determine whether the incorporation of PHED to the
PA6 melt during the melt-spinning process can provide efficient flame retardancy. For this
purpose, a PHED concentration of 15 wt% was used, as flame self-extinguishment of the
PA6/PHED-is yarn was achieved at this concentration. The morphological properties of the
fibre surface were studied by scanning electron microscopy (SEM). The thermal properties of
the fibres, their thermooxidative stability and flammability were determined by differential
dyinamic calorimetry (DSC), thermal gravimetry (TG) and a vertical flammability test. The
tensile properties of the fibres were analysed on an Instron dynamometer. The incorporation of
the PHED additive in the melt spinning process resulted in the formation of micro-bumps on
the fibre surface. Incorporation of the PHED additive increased the thermo-oxidative stability
and reduced the burning time of the fibres after removal of the flame source from 7.6 s for the
PA6 sample to 1.6 s for the PA6/PHED sample resulting in self- extinguishment, which is a
slightly lower flame retardant efficiency compared to PA6/PHED-is. Although incorporation
of the PHED additive into the molten PA6 caused a slight decrease in melting and crystallisation
temperatures of less than 5 °C, it also caused an 88% decrease in elongation at break and a 41
% decrease in ultimate tensile strength for the PA6/PHED filament, representing twice higher
effect on degradation in tensile properties of the PA6/PHED filament.
|