中空玻璃微珠/氮化硼填充硅橡胶复合材料的介电、导热和阻燃性能研究

为满足5G电子封装材料的性能需求,将一定量的改性中空玻璃微珠(f-HGM)和氮化硼(f-BN)添加进加成型液体硅橡胶中制备了低介电、高导热且阻燃的硅橡胶复合材料。测试结果表明,添加了10份f-HGM和15份f-BN的复合材料的介电常数为2.68,介电损耗为0.008 16,显著低于纯硅橡胶,热导率为0.518 W/m·K,是纯硅橡胶的2.25倍。此外,复合材料的热稳定性得到了提升,pHRR和THR分别下降了55.3%和37.7%。通过气相和凝聚相分析发现,复合材料的气相热解产物浓度大幅降低,残炭的致密性和连续性得到显著提升。     

Dust cloud evolution and flame propagation of organic dust deflagration under low wall influence

The present study discusses experiments on organic dust explosions in a setup with low wall influence. The proposed apparatus decouples the dust dispersion and the deflagration event in two separate compartments. The use of a continuous-wave laser to illuminate the centre plane of the observation chamber allows capturing both, the dust cloud and the flame during the same experiment and eliminates typical problems caused by the limited dynamic range of high-speed cameras. A k-means clustering method is used for image segmentation to obtain the spatial extent and the propagation velocities of the unreacted particle cloud and the flame zone. Spatially resolved velocities are calculated by the additional use of an optical flow method. The main goal of the presented setup and image processing method is to provide high quality validation data for the development of numerical models on dust deflagration.