Study On The Synergistic Flame-retardant Polypropylene Of Hyperbranched Triazine Char-forming Agent And Nano-filler

In order to solve the problem of the flammability of polypropylene?PP?,a kind of hyperbranched triazine char-forming agent was designed and synthesized.Meanwhile,a series of flame retardant PP composites were prepared by nanocomposite technology with the goal of solving the high loading and mechanical deterioration causing by traditional intumescent flame retardant?IFR?on PP composites.This thesis is mainly divided into the following parts:?1?The ethylenediamine hyperbranched triazine?HECA?was synthesized by"one-pot"method.The results showed that it exhibited good thermal stability and water resistance.The flame retardant property of the PP composites with 25 wt%loading?APP:HECA=3:1 in IFR?could achieved UL-94 V-0 rating.The flame retardant mechanisms of the flame retardant system was also studied,and it was concluded that the IFR dehydrated and produced crosslinked charing layer during the PP composites combustion under the catalysis of phosphoric acid.The excellent synergistic effect of P,N and C played an effective role in flame retardancy.?2?A carbon-based hybrid material,MAH-g-CFs,was synthesized via a simple solvothermal method.When the addition of MAH-g-CFs was 3 wt%and IFR was 22 wt%,the PP composite reached UL-94 V-0 rating.The flame retardant mechanism of the composites was the synergistic effect of phosphorus and nitrogen plays a key role in the improvement of flame retardancy.Meanwhile,MAH-g-CFs served as a physical support in the flame retardant system.Moreover,MAH on MAH-g-CFs can improve the interfacial interaction and improve the mechanical properties of composites.?3?The organosilicon was introduced into the flame retardant system by two kinds of synthesis methods.The result showed that the silicone had excellent synergistic flame retardant effect with IFR,which could effectively reduce the addition of IFR.The composites could still maintain good flame retardancy when the content of IFR was 20 wt%.Scanning electron microscope?SEM?showed that SiO₂ microspheres filled carbon layer and served as a physical barrier in the expanded charring layer.Moreover,the compact charring layer made immense contribution to the improvement of flame retardant efficiency.In addition,the expanded charring layer formed by microsphere and IFR prolonged the escape path of smoke and thus the composites achieved remarkable smoke suppression effect.