静电喷雾法制备n-Al/PVDF复合粒子及其放热性能研究

Study on Electrospray Formation of n-Al/PVDF Composite Particles and Exothermic Properties

采用静电喷雾法制备核壳结构纳米铝粉/聚偏二氟乙烯(n-Al/PVDF)复合粒子。为优化制备参数,设计了正交试验,利用扫描电子显微镜(SEM)、透射电子显微镜(TEM)、差示扫描量热仪(DSC)等设备研究了静电喷雾过程中针头内径、推进速率、输出电压、接收距离等4种因素对制备的复合粒子形貌和放热性能的影响。结果表明:在0.51mm针头内径,1mL/h推进速率,10cm接收距离,12kV输出电压条件下制备的复合粒子形貌最为规整,平均粒径为75nm,与原料n-Al颗粒基本一致;PVDF包覆层厚度均匀,平均厚度为5nm。DSC测试结果显示,按此条件制备的样品在惰性气氛及空气气氛条件下放热量最大,且均大于其他条件下制备的样品,PVDF包覆层能够显著改善n-Al粉末能量释放效率,使铝粉反应更完全。

Nano Al/PVDF composite particles with a core-shell structure were prepared by electrospray method.In order to optimize the formation parameters,including the inner diameter of the needle,the injection rate,the driving voltage,and the receiving distance,an orthogonal experiment was designed and carried out.Scanning electron microscopy(SEM),transmission electron microscopy(TEM),and differential scanning calorimetry(DSC)were employed to assess the morphology and the exothermic properties of the as-prepared composite particles.The results presented that the composite particles had best morphology in appearance produced in optimized conditions like a needle inner diameter 0.51 mm,an injection rate 1 mL/h,a receiving distance 10 cm and a driving voltage 12 kV.The composite particles had an average diameter 75 nm which was in accordance with the raw n-Al powders.TEM results indicated that the PVDF coating was even whose thickness was around 5 nm.According to DSC results,the sample in optimized conditions had the highest heat release both in N2 atmosphere and air atmosphere.Moreover,the PVDF coating could significantly improve the energy release efficiency of nAl powders resulting in much more aluminum oxidized.