苯并噁嗪树脂及其玻璃纤维增强复合材料的阻燃改性

应用聚磷酸铵(APP)对苯并噁嗪(BOZ)树脂及玻璃纤维(GF)/BOZ复合材料进行了阻燃改性,结合热分析和微观形貌分析等研究了材料的阻燃机制。结果表明:APP可以明显提高BOZ树脂的阻燃性能,随APP含量的提高,树脂体系的极限氧指数逐渐提高,添加量为3wt%时可使BOZ树脂的极限氧指数从基体的31.5%提高到34.5%,并达到UL 94V-0级。APP的加入使改性树脂体系的分解温度前移,玻璃化转变温度略有下降,改性树脂体系固化反应提前,反应过程变得缓和。APP的加入使GF/BOZ复合材料的阻燃性能进一步提高,10wt%GF/APP-BOZ复合材料的极限氧指数从GF/BOZ的51.0%提高到57.7%。微观形貌分析表明:APP的加入使APP-BOZ改性树脂及GF/APP-BOZ复合材料燃烧后生成更为致密的炭层,从而使材料的阻燃性能得到提高。

Flame retardant modification of benzoxazine resin and its glass fiber reinforced composites

Ammonium polyphosphate (APP) was used as flame retardant to modify benzoxazine (BOZ) resin and glass fiber (GF) /BOZ composites. The flame retardant mechanism of material was investigated by thermal analysis and microstructure analysis. The results show that APP can significantly improve the flame retardancy of BOZ resin. With the increase of APP content, the limiting oxygen index of resin system increase gradually. The limiting oxygen index of 3wt% APP-BOZ resin increases from 31.5% of matrix to 34.5% and the UL 94 of V-0 is obtained. The APP-BOZ modified resins decompose earlier than BOZ resin, and the glass transition temperatures reduce a little. The curing reactions of modified resin system start at lower temperatures and operate more mildly. With the incorporation of APP, the flame retardancy of GF/BOZ composites gets further improved, and the limiting oxygen index of 10wt% GF/APP-BOZ composites increases from 51.0% of GF/BOZ to 57.7%. Microstructure analysis shows that APP can help to form denser char of APP-BOZ modified resins and GF/APP-BOZ composites to improve the flame retardancy.