DOPO钠盐官能化LDH的制备及其阻燃环氧树脂性能

Preparation of DOPO-based sodium salt functionalized LDH and its application in flame retarding epoxy resins

首先以9,10-二氢-9-氧杂-10-磷杂菲-10-氧化物(DOPO)、双氧水和无水碳酸钠为原料合成了DOPO钠盐(DOPO-ONa),再将镁铝双氢氧化物(LDH)经高温焙烧、DOPO-ONa改性、水中重建过程,成功制备DOPO-ONa官能化LDH(R-D-LDH),采用X射线衍射(XRD)、紫外可见(UV-Vis)光谱和热失重(TG)表征其结构。制备含R-D-LDH环氧树脂,采用UL-94垂直燃烧、极限氧指数(LOI)和锥形量热、热失重(TG)、差示扫描量热(DSC)测试分析R-D-LDH加入对环氧树脂阻燃和热性能的影响。结果表明,LDH经DOPO钠盐官能化后能提高阻燃效率。与含LDH环氧树脂相比,含R-D-LDH环氧树脂燃烧程度降低,具有较高的LOI值。R-D-LDH降低环氧树脂燃烧的强度和抑制烟的产生。当加入6%(质量分数)R-D-LDH时,使环氧树脂的LOI值由23.7%提高至24.6%;燃烧时热释放速率峰值(PHRR)、总释放热(THR)和总烟产量(TSR)分别降低211kW/m^2、13MJ/m^2、1229m^2/m^2,残炭率提高幅度为58%;且维持基体的玻璃化转变温度(Tg)为160.6℃,其初始分解温度(T5%)高达365.7℃。

DOPO-based sodium salt (DOPO-ONa) was successfully synthesized from 9,10-dihydro-9-oxa-10-phosphorphenanthrene-10-oxide (DOPO),aqueous hydrogen peroxide solution and anhydrous sodium carbonate.Then,DOPO-based sodium salt functionalized LDH (R-D-LDH) was successfully prepared by the high temperature roasting of LDH,DOPO-ONa- modification and reconstruction in water,and its structure was characterized by XRD,UV-Vis and TG.The epoxy resins containing R-D-LDH was prepared,and its flame-retardant and thermal properties were studied by using UL-94 vertical burning,LOI,cone calorimeter,TG and DSC.The results indicated that the flame-retardant efficiency of LDH was improved after functionalization by DOPO-based sodium salt.Compared with the epoxy resins containing LDH,the epoxy resins containing R-D-LDH showed the reduced burning degree and had the higher LOI values.The combustion intensity and smoke production of epoxy resin were decreased by the incorporation of R-D-LDH.When 6 wt% R-D-LDH was introduced into epoxy resin,the LOI value of epoxy resin was increased from 23.7% to 24.6%.And during combustion,its PHRR,THR and THR were decreased by 211 kW/m^2,13 MJ/m^2 and 1 229 m^2/m^2,respectively,and its increase range of the residue was 58%.Moreover,its T gwas 160.6 ℃,which was same as the pure epoxy resin,and its T 5% was as high as 365.7 ℃.