双马来酰亚胺泡沫的微观形貌与结构控制研究

以偶氮二甲酰胺(AC)为发泡剂制备了改性双马来酰亚胺(BMI)泡沫,用扫描电镜(SEM)对泡沫的微观形貌进行观察,研究泡沫的发泡过程及不同条件下泡沫的泡孔结构,包括密度、孔径、单位体积的泡孔数目、发泡倍率等。结果表明:改性的BMI泡沫是一种闭孔结构泡沫,其构型为排泄型十二面体。可通过发泡体系的黏度、温度和发泡剂含量控制BMI泡沫的结构,随发泡体系黏度的增加,泡沫密度,成核密度N0和单位体积的泡孔数目Nf增加,泡孔直径减小,均匀性变好。泡沫密度随发泡剂AC含量提高而降低,当AC含量超过7%(质量分数)时,泡沫密度反而上升。随发泡温度提高,泡沫密度降低,孔径增大,泡沫成型稳定性变差。

Study on Micro-morphology and Structure Control of Bismaleimide Foams

Bismaleimide(BMI) foams were prepared using azodicarbonamide(AC) as the foaming agent.Micro-morphology of the foams were analyzed by scanning electron microscopy(SEM) and the foaming process and foamed structure such as cell size,cell density,expansion ratio etc.were also studied.The results showed that the modified BMI foam was a kind of closed-cell foam and its cell shape was pentagonal dodecahedron.The foamed structure can be controlled by foaming viscosity,temperature and foaming agent content.When the viscosity of foaming mixture was enhanced,foam density,cell nucleation density(N0) and cell density(Nf) increased,the cell diameter was decreased and become uniformed.The foam density was reduced with increased AC content,and it increased when AC content was over 7%.With the elevated foaming temperature,the cell size increased and the foaming stability became worse.