| Epoxy resin(EP)is one of the most useful thermosetting polymers.It is widely applied in chemical,electrical,construction,transportation,aerospace military and other fields.However.EP has flammability,it will release a lot of smoke in the burning process,and with the dripping,it is easy to cause fire accidents,which poses a threat to personal safety and property safety,as well as the natural environment,so its application is limited.In response to the above problems,flower-like nickel phyllosilicate(Ni-PS)was synthesized using hydrothermal method to prepare flame-retardant EP.In order to further improve the flame-retardant effect,Ni-PS was modified with iron-containing compounds and flower-like nickel phyllosilicate containing iron(Fe@Ni-PS)was prepared.The effects of Fe@Ni-PS on the flame retardant properties and thermal stability of EP were studied.The main contents of this paper are summarized as follows:1.Firstly,flower-like nickel phyllosilicate(Ni-PS)was synthesized from SiO2 and nickel chloride hexahydrate by hydrothermal method.The chemical structure and morphology of Ni-PS were analyzed by characterization methods,which confirmed that Ni-PS was successfully prepared.Then Ni-PS was used as the flame retardant of EP to prepare a series of EP/Ni-PS composites,and the flame retardant and thermal stability properties were studied.The test results of limited oxygen index test(LOI)and vertical burning test(UL-94)showed that the flame retardancy of EP composites was significantly improved when the addition of Ni-PS added was 4 wt%.The LOI value increased from 24.4%of pure EP to 27.2%,and the burning time of EP composite decreased from 142.7 s of pure EP to 50.1 s.The cone calorimetry test(CCT)results showed that the peak of the heat release rate(pHRR),total heat release(THR)and the peak of smoke production rate(pSPR)of EP/Ni-PS composites were 856.81 kW/m2,100.69 MJ/m2 and 0.37 m2/s,respectively,which were 15.6%,4.0%and 15.9%lower than those of EP.Thermogravimetric analyses(TG)results showed that the thermal stability of EP/Ni-PS was significantly improved,and the char residue increased from 5.3 wt%of pure EP to 25.0 wt%.2.In order to further improve the flame retardancy of EP,Fe@Ni-PS was prepared with Ni-PS and ferric nitrate nonahydrate as raw materials.By analyzing the chemical structure and morphology of Fe@Ni-PS,it was determined that Fe@Ni-PS was successfully prepared.Using Fe@Ni-PS as the flame retardant of EP,a series of EP/Fe@Ni-PS composites were prepared.The flame retardancy and thermal stability of EP composites were studied.The LOI test results showed that when the addition of Fe@Ni-PS was 4 wt%,the LOI value of EP composites increased to 28.9%,which was 18.4%higher than pure EP.UL-94 test results showed that EP/Fe@Ni-PS can self-extinguish after only 12 s after ignition,and the amount of smoke was significantly reduced,and it passed the UL-94 V-1 level test.The CCT results showed that the pHRR,THR and pSPR of EP/Fe@Ni-PS composites were 810.86 kW/m2,99.89 MJ/m2 and 0.34 m2/s,respectively,which were reduced by 20.1%,4.7%and 22.7%compared with pure EP.The TG results showed that the addition of Fe@Ni-PS can significantly improve the thermal stability of EP composites,and the residual content was also increased to 37.2 wt%.Scanning electron microscopy(SEM)of the char layer showed that EP/Fe@Ni-PS composite can form a more complete and continuous char layer,play the role of heat insulation and oxygen isolation,which can effectively protect the EP matrix and improve the fire safety of the composite.Figure 39 Table 11 Reference 156... |
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