| Nitrile Butadiene Rubber(NBR) possess a large amount of-CN groups beside the main molecular chain, Which endow NBR excellent properties, such as oil and solvent resistance, heat resistance, wearable and good mechanical characteristics, consequently NBR can be widely used in fields like petroleum industry, transportation system, aviation technology, press and building material area. Nevertheless, the limited oxygen index(LOI) of NBR is around 22% that makes it is a kind of combustible rubber and its products cannot meet fire-retarding request in area mentioned above. Therefore, it is of great social and economic significance to research and develop high quality flame-retarding NBR products.This thesis adopted the way of modifying the NBR matrix by epoxy structure, in which the flame retardant was chemically bonded to the molecule skeleton of NBR, improving the dispersion and bonding strength of the flame retardant in matrix from molecule structure, and obtaining the NBR material with excellent fire resistance. APP is an efficient flame retardant containing phosphorus and nitrogen two elements, while large hygroscopicity and poor compatibility with the polymer material. Through the reaction between oxygen-containing groups generated by epoxy modification and APP during mixing improves the compatibility of APP and the bonding strength with the substrate, thereby enhancing the flame retardant efficiency of APP. When the content of APP was 50 phr, LOI value of ENBR/APP was 33.5%, increased 10.2% when compared with NBR/APP, when the amount of APP was 40 phr, vertical burning pass the UL-94V-0 grade, values of Peak Heat Release Rate(PHRR) and average Heat Release Rate(av-HRR) were 518.3kW/m2 and 192.5k W/m2, decreased by 15.3% and 14.9% respectively when compared with NBR/APP, char residue at 700℃ was 42.2wt%, increased by 14.1%.Mg(OH)2 is chosen as flame retardant and reinforcing particles to enhance the mechanical properties and flame retardant properties of ENBR, which is due to oxygen containing groups in ENBR interact with Mg(OH)2 improved crosslinking density of ENBR. Furthermore, we also studied the effect of Sb2O3 as synergistic flame retardant to MDH/ENBR compound system. The experiment results show that Sb2O3 can improve the dispersion of MDH in the rubber matrix and inhibit the agglomeration effect, when the amount of Sb2O3 is 7.5Phr, tensile strength reached the maximum value of 12.58 MPa compared with the blank sample there is 10.7% increased. Sb2O3 have a synergistic effect in ENBR/MDH composites significantly, when the total amount of flame retardant is 40 phr, the dosage of Sb2O3 is 7.5phr, the synergistic efficient of Sb2O3 and MDH reaches a maximum value of 1.62, the LOI value increase from 26.5% to 27.9%, and past the UL-94 V-0 test.In addition, we also discussed the degradation dynamics and mechanism of flame-retarding of ENBR, ENBR/MDH and ENBR/MDH/Sb2O3 by modern test and analysis technique. |
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