摘要:
研究了羧基碳纳米管(CNT-COOH)增强酚醛泡沫复合材料的制备工艺、微观结构、压缩性能和热性能,并结合红外光谱和泡沫在不同压缩应变下的变形破坏形貌,探讨了CNT-COOH对酚醛泡沫的增强机制。结果表明,CNT-COOH作为异相成核剂,使酚醛泡沫泡孔的平均尺寸减小,泡孔密度增大; 随着酚醛泡沫中CNT-COOH含量增加,CNT-COOH/酚醛泡沫复合材料的压缩模量和压缩强度提高。红外分析表明,CNT-COOH可能未与酚醛泡沫发生固化反应。CNT-COOH/酚醛泡沫复合材料在不同压缩应变下的SEM分析表明,CNT-COOH位于泡孔的孔壁上,并通过CNT-COOH/酚醛泡沫的界面传载作用承受了一定载荷,增强了泡沫的力学性能。热重分析和垂直燃烧试验表明,CNT-COOH作为稳定剂,降低了泡沫的热降解速率,使其热稳定性和阻燃性能均略有提高。
Abstract:
The fabrication, microstructure, compressive property and thermal performances of the phenolic foam reinforced with carboxyl carbon nanotubes(CNT-COOH) were studied. The reinforcement mechanism of CNT-COOH was investigated by analyzing FTIR and detailed failure behavior of 0.05%(mass fraction) CNT-COOH/phenolic foam composite and phenolic foam under different compressive strains. It is found that serving as the site of heterogeneous nucleation, CNT-COOH increases the cell density and decreases the cell size of the produced foams, and that CNT-COOH reinforced foams are evidently stiffer and stronger than the corresponding neat system as the increment of CNT-COOH content. FTIR reveals that curing reaction of CNT-COOH and phenolic resin may not exist. SEM analysis of the composite foams in different compressive strains reveals that adding CNT-COOH located in the cell walls could endure a certain load through the interface between CNT-COOH and phenolic resin, thereby enhancing the compressive strength of CNT-COOH/phenolic foam composites. In addition, thermogravimetric analysis (TGA) and vertical burning method show that CNT-COOH as stabilizer, reduces thermal degradation rate, leading to slightly higher thermal stability and resistance to flame of the foam composites.
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