However, the PP/MTAPP/PA6 composites exhibit an enhanced thermal stability at temperatures ranging from 450 to 700[degrees] C and have higher charred residues when the suitable amount of PA6 as a charring agent is incorporated into the PP/MTAPP composites.
However, it is found that the introduction of PA6 as a charring agent to PP/MTAPP composites leads to a great improvement in the mechanical properties, especially for the tensile strength (samples PPMA1-3).
This work demonstrates the influence of PA6 as a charring agent on the flame retardancy and synergistic effect of intumescent flame-retardant PP composites.
Charring of wood is also dependent on the heat load applied on the structural surface and change in the value of heat load depending on the length of thermal exposure (Taubkin 1999).
To identify charring peculiarities in wood of different species at different temperatures, special one-side heating equipment was used (Lukosius 2004; Lipinskas, Maciulaitis 2005).
After the sample cooled down, the charring depth H, mm of wood under research was measured using sliding callipers.
The results of charring research, which was carried out with different species of wood using one-side heating chamber, are shown in Figs 10 and 11.
The values of the charring rate for the wood samples are presented in Fig.
Friquin (2010) compares different factors affecting the charring rate.
Syme (1994) found an effect of wood density on the charring depth in Australian tests with fire similar to ISO 834 fire.
4 consist of rules for calculating notional charring rate dependent on density:
where C--notional charring rate (mm/min); D--wood density with moisture content 12% (kg/[m.