利用热重法比较了两种不同烷基次膦酸锌及其阻燃环氧树脂(EP)复合材料的热性能.首先探究甲基环己基次膦酸锌(Zn(MHP))、甲基乙基次膦酸锌(Zn(MEP))、Zn(MHP)/EP、Zn(MEP)/EP在N2氛围下的热稳定性. 然后运用Kissinger 法、Flynn-Wall-Ozawa(简称FWO法)计算出EP、Zn(MHP)、Zn(MEP)、EP/Zn(MHP)、EP/Zn(MEP)) 热分解活化能E、指前因子lnAk,并结合Coast-Redfern理论模型机理函数g(α),求得反应级数n.结果表明,Zn(MHP)比Zn(MEP) 具有更高的热稳定性和表观热分解活化能.同时Zn(MHP)或Zn(MEP)能明显提高EP的热稳定性能,延迟EP的分解、提高残碳率和热分解活化能.当添加量为均为20%(质量分数)时,EP/Zn(MHP)的热分解活化能高于EP/Zn(MEP).Coats-Redfern法推断Zn(MHP)的热分解机理为g(a)=-ln(1-α),反应级数即为1,Zn(MEP)的机理函数为g(a)=3[1-(1-α)1/3],反应级数为1/3.EP/Zn(MHP)和EP/Zn(MEP)的热分解机理函数与EP一致,均为g(a)=[-ln(1-α)]2/3,反应级数为2/3.
In this study, thermal stability and decomposition kinetics of Zn(MHP) and Zn(MEP) as well as epoxy(EP) flame retardants system were investigated by thermogravimetric analysis.The average activation energy (Ea) and pre-exponential factor A of decomposition were calculated with Flynn-Wall-Ozawa (FWO) and Kissinger method.Coats-Redfern method was used to discuss the probable degradation mechanism by selection of different mechanical models.The results show that the Ea value obtained from Kissinger method is in good agreement with the value from FWO method.Zn(MHP) shows higher thermal stability and has higher Ea value than Zn(MEP).Adding Zn(MHP) or Zn(MEP) into EP can improve the thermal stability and delay the Ea of EP, the char residue and the decomposition of EP.When the filler loading is kept at 20wt%, EP/Zn(MHP) has higher Ea than EP/Zn(MHP).The solid state decomposition mechanism with Coats-Redfern method for Zn(MHP) is in accordance with the function of g(a)=-ln(1-α) with n=1.The decomposition mechanism of Zn(MEP) corresponds to the function of g(a)=3[1-(1-α)1/3]with n=1/3.EP/Zn(MHP) and EP/Zn(MHP) have the same thermal decomposition mechanism, which proposes to the function of g(a)=[-ln(1-α)]2/3 with n=2/3.
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