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苯并噁嗪是一种类似酚醛树脂的开环固化型热固性树脂,具有一定的耐热性和阻燃性,但在阻燃要求高的场合使用时,需要进一步改善其阻燃性、力学性能及工艺性。而已有的阻燃改性方法较难实现在提高树脂阻燃性的同时兼顾其力学性能和工艺性。采用一种具有增韧作用的耐高温超支化聚合物—超支化聚硼酸酯(HBPB),在改善苯并噁嗪树脂力学性能和固化工艺性的基础上对其进行阻燃改性。加入2.5或5.0wt%的HBPB后,苯并噁嗪树脂的800℃(氮气)残碳率可由46.0%提高至50.9%和54.8%;阻燃性能明显提升,由UL-94V1提高到UL-94V0级,苯并噁嗪树脂的极限氧指数也由24%增加到30%和33%。HBPB改性苯并噁嗪树脂燃烧产物表面形成的致密表面结构,是树脂阻燃性提高的重要原因。
Benzoxazine is a kind of phenolic resin-ring-opening curing type thermosetting resin, has a certain heat resistance and flame retardancy, but in the case of high flame retardancy requirements, the need to further improve its flame retardancy, mechanical properties And crafts. The existing flame retardant modification method is more difficult to achieve in improving the flame retardant resin while taking into account its mechanical properties and processability. A toughening-tolerant hyperbranched hyperbranched polymer (HBPB) was used to improve the mechanical properties and curing process of benzoxazine resin. After adding 2.5 or 5.0wt% HBPB, the residual carbon of 800 ℃ (nitrogen) of benzoxazine resin increased from 46.0% to 50.9% and 54.8%, and the flame retardancy increased obviously from UL-94V1 to UL-94V0 The limiting oxygen index of benzoxazine resin also increased from 24% to 30% and 33%. The dense surface structure formed on the surface of the combustion products of HBPB modified benzoxazine resins is an important reason for the flame retardancy of the resin.