Study on synergistic expansion and flame retardancy of modified kaolin to low density polyethylene. (14th April 2021) - Ou, Hongxiang
Abstract: To improve the flame retardancy of low density polyethylene (LDPE), the intercalation of modified kaolin with urea (KU) was prepared by mechanochemical method and combined with intumescent flame retardant (IFR) as LDPE flame retardant in this paper. KU was used as synergistic flame retardant. The mechanical properties, flame retardant properties and smoke properties of KU/SiO2 @MAPP/DPER/LDPE composites were investigated. The results demonstrated that the intercalation rate of KU was 63% and the addition of KU effectively improved many aspects of LDPE's performance. When 3 wt% KU were added, the LOI of SiO2 @MAPP/DPER/LDPE increased from 24.1% to 27.2% and the UL-94 reached V-1. The tensile strength was 16.6 MPa and the elongation at break was 554%. The smoke density test showed that the flue gas emission was obviously improved. Raman test showed that the R value of LDPE3 was 0.96. The addition of KU effectively increased the residual carbon content of composites and thermal stability of the composites. Graphical abstract: Combustion performance mechanism diagram of composite materials. Image 1 Highlights: The modified kaolin (KU) was prepared by mechanochemical method. The method was simple and environmentally friendly. Combined KU with DPER and SiO2 @MAPP, a novel halogen-free intumescent flame retardant was synthesized. The addition of KU improved the thermal stability, mechanical properties of LDPE, and the graphitization of carbon residue.