硬质聚氨酯/二氧化硅纳米粒子复合材料泡沫形貌和性能研究

Morphology and Properties of Silica Nanosphere/Rigid Polyurethane Composite Foams

利用2种不同粒径的球形二氧化硅(SiO_2)纳米粒子作为填料,制备了硬质聚氨酯(PU-R)/SiO_2纳米粒子复合材料泡沫。利用扫描电子显微镜考察复合材料的形貌,通过压缩试验、尺寸稳定性测试和热导率测试表征复合材料的力学性能、尺寸稳定性和热导率。结果表明,球形SiO_2纳米粒子对复合材料的泡孔结构有明显的细化作用(孔径从纯PU—R泡沫的303μm降低到170μm),可以有效提高复合材料的压缩性能(与纯PU-R泡沫相比,比强度和比模量分别提高了8.3%和12.5%),降低了其线膨胀系数,并使热导率略微下降,而对尺寸稳定性无明显影响。与粒径为400 nm的SiO_2纳米粒子相比,粒径为700 nm的SiO_2纳米粒子较易均匀分散,对PU-R泡沫力学性能的改善效果更为明显。

Two kinds of silica （SiO2） nanospheres were introduced into rigid polyurethane （PU-R） forming PU-R/SiO2 composite foams. Morphology of the composite foams was characterized by SEM. Mechanical properties, dimensional stabilities, and thermal conductivities of the composite foams were investigated by compressive test, dimensional stability test, and thermal conductivity measurements, respectively. It showed that, the cellular size of the composite foams was lowered obviously （from 303 μm of neat PU-R foam to 170 μm of the composite foam）, the compressive properties were improved effectively （the specific compressive strength and specific compressive modulus increased by 8. 3 % and 19.5%, respectively, compared with those of neat PU-R foam）, the coefficient of linear thermal expansion was decreased, the thermal conductivity was reduced slightly, and the dimensional stabilities almost keep invariable, after the introduction of SiO2 nanospheres. In addition, compared with 400 nm sized ones, 700 nm sized SiO2 nanospheres could be dispersed more homogeneously, and lead to better mechanical properties.