The flammability of expandable polystyrene foams coated with melamine modified urea formaldehyde resin
writer：曹博，谷曉昱，宋曉卉，金曉冬，劉新瑜，劉曉東，孫軍*，張勝*
keywords：applications, flame retardance, foams,polystyrene, resins
source：期刊
specific source：Journal of Applied Polymer Science
Issue time：2017年
Urea formaldehyde resin (UF) was modified by introducing melamine during the condensation in order to reduce the amount of free formaldehyde and increase the solid content. The melamine modified UF (MUF) was firstly mixed with intumescent flame retardant (IFR) and then coated on the surface of pre-expanded polystyrene (PS) particles to prepare flame retardant expandable PS (EPS) foams. Theflammability of EPS foam samples was characterized by limiting oxygen index (LOI), UL-94 vertical burning and cone calorimeter tests, and the results indicated that the peak heat release rate was significantly reduced from 406 to 49 kW/m(2) and LOI value could reach 36.3 with V-0 rating in UL-94 test after coated with IFR. The smoke density test indicated that the maximum smoke density was decreased by the addition of IFR. Thermal analysis suggested that the thermal stability and char formation were significantly improved by the presence of coated flame retardants. The residual char observation revealed that MUF and IFR were beneficial to form integrated char layers with hollow stents, which could be the main reason for the improvement of flame retardant properties. Themechanical properties of flame retardant EPS foams can still meet the standard requirements for industrial applications.