Zinc oxide (ZnO) is one of the most popular photocatalyst metallic compounds because of its advantages, such as, cost efficiency, numerous active sites, high surface reactivity, and low environmental impacts. In fact, it is listed as safe by the US Food and Drug Administration given that zinc is an essential trace element. ZnO particles have high thermal conductivity as well as great heat capacity. Therefore, incorporating them into polymeric compounds will result in absorbing the heat transmitted from the surroundings and retarding the direct thermal impact to the polymer backbone. In other terms, they act as an inhibitor to slow down the flame spread rate.
With recent advancements in nanotechnology, nano-sized zinc oxides are among the emerging high-value inorganic products with significant features, (such as, high catalyst effect, effective antibacterial properties, high UV absorption, high thermal and physical stability, and high heat capacity) that have many applications in different industries, such as, cosmetics, plastics, sensors, and semiconductors.
It is common to use high concentration of inorganic mineral fillers, such as, Al(OH)3 up to 20 wt% to modify flame retardancy of polyvinyl chloride (PVC). However, it is reported that the addition of only 0.635 wt% of ZnO and 9 wt% of Al(OH)3 combination into PVC can significantly increase the LOI value of PVC nanocomposite (up to 30%). This observation was more likely due to the formation of crosslinked surface modified ZnO in polymer matrix, which accelerate the nucleation process and improve the heterogeneous nucleating ability in the cross linked polymer matrix.
Intumescent Flame Retardant systems (IFRs) are FRs that can insulate materials during combustion through the formation of an expanded carbonized layer. These systems usually require three components: an acidic source, a carbonization source, and a blowing agent. ZnO-intumescent Flame Retardant (IFR) system has been reported to be effective in flame retardancy property of the polypropylene-ethylene-propylene-diene monomer (PP-EPDM) polymer blend. The IFR used here was self-designed out of poly ammonium phosphate (acid source), dipentaerythritol (carbonization agent), and melamine (blowing agent). Addition of 1 wt% ZnO and 29 wt% IFR showed the best fire performance as that formulation exhibited an LOI value of 35.6% compared with 17% LOI of original PP-EPDM blend. Furthermore, a heat release peak (pHRR) appeared for the formulation containing ZnO, reflecting the better barrier effect of the char layer compared to the original polymer blend and also formulations containing only IFR. Uniformly dispersed ZnO particles assist the IFR to have a more homogenous and compact char layer. Moreover, great heat capacity of them would result in absorbing the heat transferred from the combustion and creating a more effective char layer.
Novista Group supplies equivalent of FP-2100JC, FP-2200S, FP-2500S, Exolit OP1230, OP930, OP1312, OP1314 to global market.
