Study On The Synthesis And Application Of Novel Phosphorous-nitrogen-containing Halogen-free Flame Retardant

In recent years, with people’s emphasis on environmental protection and increasingly perfecting flame retardant related laws and regulations, the demand of halogen-free and environmentally friendly retardant has been increased. Intumescent flame retardant system with nitrogen and phosphorus as the main component, which has the acid source, carbon source and gas source at the same time and the advantage of environmental protection, high efficiency, low smoke and low toxic, has become the main development direction of the halogen-free flame retardant. In this paper, a novel phosphorous-nitrogen-containing halogen-free flame retardant was prepared in which phosphoric was used as the acid source, melamine (MA) and piperazine (PI) was used as the carbon source. The flame retardant was added to polypropylene (PP) and thermoplastic elastomer (SEBS/PP) to form a flame retardant complex system, of which the retardant mechanism and overall performance was also studied. The main contents of this dissertation are summarized as follows:A novel pyrophosphate-based flame retardant (MPIPP) was synthesized with melamine, piperazine and phosphoric acid as raw materials. With the conditions such as the raw material ratio, reaction time and reaction temperature selected, the optimal coordination flame retardant properties were achieved. By infrared spectrum (IR), elemental analysis (EA), nuclear magnetic resonance analysis (13C-NMR) and thermal gravimetric analysis (TG), the molecular structure and thermal stability of MPIPP was characterized. The results showed that MPIPP has good thermal stability, and the melting temperature is 280℃. The addition of MPIPP can greatly improve the thermal stability and flame retardancy of PP, while exhibiting excellent char-forming capacity. Meanwhile, MPIPP has good compatibility in PP, so that the mechanical properties of flame retardant PP were less affected by the flame retardant.Using a twin-screw extruder, the flame retardant SEBS/PP composites were prepared with the mixture of paraffin oil modified SEBS and PP as a matrix and MPIPP as flame retardant. The impact of Oil, PP and MPIPP on flame retardancy, mechanical and rheological properties of SEBS/PP composites was discussed, while comparing the overall performance of domestic flame retardant NP430C and imported flame retardant ADK-FP-2200 in the SEBS/PP composites application. The results showed that the LOI of composites is 30.3% and the composites could pass V-0 (3mm) rating in UL-94 tests when added 30% MPIPP; The addition of MPIPP and NP430C could have a greater impact on mechanical properties of SEBS/PP composites than ADK-FP-2200.