成核剂对硬质密胺泡沫泡孔结构及性能的影响

Influence of nucleating agent on cell structure and performance of rigid melamine foam

采用丁醇改性密胺树脂为原料,使用烘箱发泡制备以钠基蒙脱土(Na^(+)-MMT)、二甲基二氯硅烷表面处理的气相白炭黑、微米及纳米白炭黑为异相成核剂的新型硬质密胺泡沫复合材料。利用扫描电镜对泡孔微观结构进行观察,并使用万能试验机、氧指数仪、导热系数仪等对泡沫性能进行了表征。结果表明:成核剂种类对泡孔形貌影响较大,纳米白炭黑成核效果最好,不仅可以作为增强填料提高泡沫力学性能,还可以改善泡孔结构降低泡孔尺寸进而影响泡沫体宏观性能。当纳米白炭黑添加量为三聚氰胺质量的1%时,所得密胺泡沫复合材料的综合性能最佳,泡孔平均直径从240μm降低至160μm,压缩强度达到252.2kPa,吸水率与导热系数分别降低了67.6%和11.9%,氧指数为32.5%。

A new type of rigid melamine foam composite material was synthesized by oven foaming with butanol-modified melamine resin used as raw material,sodium-based montmorillonite(Na^(+)-MMT)and fumed silicad was treated with dimethyldichlorosilane,micron and nano-silica used as phase nucleating agent.Scanning electron microscope was used to observe the cell microstructure,and the foam performance was characterized by universal testing machine,oxygen index meter,thermal conductivity meter,etc.The results shown that the type of nucleating agent had greater impact on the cell morphology,and nano-silica had the best nucleation effect.It can not only be used as a reinforcing filler to improve the mechanical properties of the foam,but also can improve the cell structure and reduce the cell size,Thereby affecting the macroscopic properties of the foam.When the addition amount of nano-silica was 1%of the mass of melamine,the overall performance of the obtained foam was the best.The average cell diameter was reduced from 240μm to 160μm,the compressive strength reached 252.2 kPa,the water absorption and thermal conductivity were reduced respectively with 67.6%and 11.9%,the oxygen index was 32.5%.