to the strong synergism between Cu 2 O and EDA-APP, the formation and compactness of the intumescent char layer increase. Additionally, CO, which is a toxic
gas, can be oxidized to CO 2 according to the redox cycle in which Cu
+2 is converted to Cu
0 (Fig. 7.1); this results in reduced smoke toxicity. This conversion is
reversible in the presence of oxygen, which acts as fuel for polymer combustion.
This conversion reaction presents two advantages, including a reduction in oxygen
concentration and toxic gas CO concentration. Further, it was observed that in the
presence of Cu 2 O, the HRR, THR, TSP, and COP of the polymer system are
reduced through intumescent char formation. EP nanocomposites with various
metal oxides, microencapsulated ammonium polyphosphate (MAPP), and APP
were prepared and a strong synergetic reaction was observed between Cu 2 O and
MAPP. Hence MAPP/Cu 2 O containing system showed strong FR activity with high
LOI values and achieved a V-0 rating in the UL-94 test [23]. Xu et al. [24]
synthesized PU nanocomposites with MoO 3 -GNS, Cu 2 O-GNS, and GNS alone.
There was a clear difference in the FR activities of the resultant nanocomposites;
those containing a metal oxide-GNS combination showed better FR activity with
strong smoke suppression owing to a strong synergetic effect. These combination
FRs presented several advantages, such as catalytic charring due to metal oxides
and a strong physical barrier due to GNS, which can prevent the release of combustible gases. Cu 2 O-TiO 2 -graphene oxide (GO) was synthesized by a hydrothermal method and used to prepare polyester composites. The results revealed that
even at low loadings, the FRs significantly decreased pyrolytic toxic gas evolution
and HRR compared to either Cu 2 O-TiO 2 or TiO 2 -GO nanocomposites [25].
Fig. 7.1 Illustration of a possible synergetic effect in EDA-APP and the mechanism of flame
retardation and smoke suppression [26]. Reproduced with permission from Elsevier Science Ltd
7.1 FR Polymer Nanocomposites Based on Various Nanoparticles
85
gas, can be oxidized to CO 2 according to the redox cycle in which Cu
+2 is converted to Cu
0 (Fig. 7.1); this results in reduced smoke toxicity. This conversion is
reversible in the presence of oxygen, which acts as fuel for polymer combustion.
This conversion reaction presents two advantages, including a reduction in oxygen
concentration and toxic gas CO concentration. Further, it was observed that in the
presence of Cu 2 O, the HRR, THR, TSP, and COP of the polymer system are
reduced through intumescent char formation. EP nanocomposites with various
metal oxides, microencapsulated ammonium polyphosphate (MAPP), and APP
were prepared and a strong synergetic reaction was observed between Cu 2 O and
MAPP. Hence MAPP/Cu 2 O containing system showed strong FR activity with high
LOI values and achieved a V-0 rating in the UL-94 test [23]. Xu et al. [24]
synthesized PU nanocomposites with MoO 3 -GNS, Cu 2 O-GNS, and GNS alone.
There was a clear difference in the FR activities of the resultant nanocomposites;
those containing a metal oxide-GNS combination showed better FR activity with
strong smoke suppression owing to a strong synergetic effect. These combination
FRs presented several advantages, such as catalytic charring due to metal oxides
and a strong physical barrier due to GNS, which can prevent the release of combustible gases. Cu 2 O-TiO 2 -graphene oxide (GO) was synthesized by a hydrothermal method and used to prepare polyester composites. The results revealed that
even at low loadings, the FRs significantly decreased pyrolytic toxic gas evolution
and HRR compared to either Cu 2 O-TiO 2 or TiO 2 -GO nanocomposites [25].
Fig. 7.1 Illustration of a possible synergetic effect in EDA-APP and the mechanism of flame
retardation and smoke suppression [26]. Reproduced with permission from Elsevier Science Ltd
7.1 FR Polymer Nanocomposites Based on Various Nanoparticles
85