冷冻干燥法聚酰亚胺泡沫材料的制备及性能

Preparation and Properties of Polyimide Foam Materials by Freeze Drying Method

为简化传统聚酰亚胺(PI)泡沫制备工艺,以均苯四甲酸酐(PMDA)和4,4′–二氨基二苯醚(ODA)为原料,合成聚酰胺酸(PAA)溶液,将三乙胺加入到处理后的PAA中,与水配成不同浓度的聚酰胺酸盐(PAS)溶液,采用冷冻干燥法,经冷冻干燥和高温亚胺化过程,得到PI泡沫,通过傅立叶变换红外光谱、扫描电子显微镜、热重分析、差示扫描量热分析等方法考察了不同PAS浓度下PI泡沫的结构和性能。结果表明,冷冻干燥法所制得的PI泡沫,其孔径大于5 nm,导热系数最低为0.08 W/(m·K),热分解5%时的温度在550℃左右,玻璃化转变温度均在320℃左右。这说明制得的PI泡沫材料的耐热性和耐高温性能优良。

In order to simplify the preparation of traditional polyimide （PI） foam,polyamic acid （PAA） was synthesized from pyromellitic anhydride （PMDA） and 4, 4′-diaminodiphenyl ether （ODA）. Triethylamine was added into the treated PAA to form a series of different concentrations of polyamic acid salt （PAS） with water. Using the freeze drying method,after the process of freeze drying and high temperature imidization, PI foam was formed. The structure and properties of the obtained PI foam were investigated through FTIR, SEM, TG and DSC. The results show that the size of the foam made by this method is more than 5 nm,the thermal conductivity is only 0.08 W/（m ·K）, its decomposition temperature is about 550℃when the decomposition rate is 5%,and the transformation temperature is about 320℃ . This shows that the material has excellent heat resistance and high temperature resistance.