芴基苯并噁嗪单体的合成、固化动力学及热性能

Synthesis, Curing Kinetics and Thermal Properties of Fluorene-Based Benzoxazines

以芴、苯酚、对甲氧基苯酚和多聚甲醛为原料,采用溶液法合成了直接在芴的苯环结构上进行修饰的2个新型芴基苯并噁嗪单体3-芴基-3,4-二氢-1,3-苯并噁嗪(FBZ-1)和3-芴基-6-甲氧基-3,4-二氢-1,3-苯并噁嗪(FBZ-2)。利用FT-IR,1H NMR和13C NMR对其结构进行了表征。采用示差扫描量热法(DSC)研究了2个单体的固化动力学,计算了固化反应活化能,确定了最佳固化温度。通过DSC和热重(TGA)分析了单体及其聚合物的热性能。结果表明,FBZ-1和FBZ-2呈现出典型的热开环固化特征,放热峰顶温度(5℃·min^(-1)的升温速率)分别为231.2℃,228.7℃,其聚合物初始热分解温度(热失重5%时)达290℃、299℃;850℃时的残炭率(Yc)达到40.9%和36.9%,极限氧指数(LOI)分别是33.86、32.26。

Two new fluorene-based benzoxazine monomers(3-fluorenyl-3,4-dihydro-1,3-benzoxazine(FBZ-1) and 3-fluorenyl-6-methoxyl-3,4-dihydro-1,3-benzoxazine(FBZ-2))were synthesized through the reaction of phenol/para methyl phenol with formaldehyde and 2-anlinofluorene. 2-anlinofluorene was from the nitrification and reduction of fluorene. The chemical structures were confirmed through FTIR, 1H NMR and 13C NMR analyses. The polymerization reactions of the precursors were monitored with Differential Scanning Calorimetry(DSC) and FT-IR. The curing kinetics were investigated, activation energy and optimum curing temperature were obtained. The thermal properties of cured polymers were evaluated through DSC and Thermo Gravimetric Analysis(TGA). The two fluorene-based benzoxazines show that the typical curing characteristic of the oxazine ring-opening centred at 231.2℃ for FBZ-1 and 228.7℃ for FBZ-2. The thermal decomposition temperature(5% weight loss) and the char yield(Yc) of fluorene-based polybenzoxazine at 850℃ is 290℃ and 40.9% for FBZ-1, 299℃ and 36.9% for FBZ-2. Limit oxygen index(LOI) is 33.86, 32.26, respectively.