中孔炭微球/酚醛树脂复合材料的力学及介电性能

Mechanical and dielectric properties of mesoporous carbon microsphere/phenolic resin composites

以间苯二酚-甲醛为前驱体、喷雾干燥法可规模制备出中孔炭微球,进一步采用聚乙烯醇对其进行表面致密化处理,再与酚醛树脂热压成型得到中孔炭微球/酚醛树脂复合材料,系统研究了复合材料的力学性能及介电性能。结果表明,所制炭微球具有较窄的粒径分布(1~10μm)、发达的中孔孔隙(孔容>3.0 cm^3/g)。经表面包覆后,中孔炭微球表面致密,形成类"蛋壳"结构。当用于复合材料填料(0~10%)时,能有效的降低复合材料的密度(1.36g/cm^3至1.12 g/cm^3),并显著提升复合材料的力学性能(压缩强度由106MPa增加至168MPa);在102~107Hz频率下,复合材料的介电常数随着炭微球添加量的增加逐渐提高,由4.0~3.6提高至10.4~9.1。结果表明,中孔炭微球可作为新一类多功能填料,在降低复合材料密度的同时增加力学性能,并在较宽频率下具备高的介电性能,具有优异的低密度吸波基体材料的应用潜力。

Mesoporous carbon microspheres （MCMs） were prepared by a scalable spray-drying method using resorcinol-formalde-hyde resin as the carbon precursor. The MCMs were used as low density fillers of phenolic resin matrix composites for microwave absorption. They were coated with polyvinyl alcohol （PVA） before being added to the phenolic resin and the composites were pre-pared by the hot-pressing method. Results showed that the MCMs had a narrow particle size distribution of 1-10 μm and developed mesopores with a total pore volume of 3. 0 cm3 /g. The PVA coating densified the surface of the MCMs to form a core-shell struc-ture while retaining the mesopores. The density of the composites decreased from 1. 36 to 1. 12 g/cm3 by increasingthe MCM con-tent from 0 to 10 wt% . The corresponding dielectric constant in the frequency range of 102-107 Hzincreased from 4. 0-3.6 to 10.4-9.1. The compressive strength exhibited a maximum of 168 MPa with a MCM content of 5 wt% . The low density,high mechanical strength and high dielectric constant of the composites suggests that the MCMs are ideal fillers for phenolic resin-based microwave absorption materials.