基于BP神经网络的聚偏氟乙烯/聚丙烯梯度复合滤料工艺优化

Process optimization of polyvinylidene fluoride/polypropylene gradient composite filter media based on BP neural network

  • 摘要: 口罩是防止病毒通过呼吸系统和黏膜进入人体的重要防疫屏障。一次性口罩存在过滤效率随静电衰减下降快、呼吸阻力大、使用寿命短等问题。将静电纺纳米纤维膜与熔喷布复合,减少颗粒物过滤性能对静电作用的依赖,实现长效过滤。以N, N-二甲基甲酰胺(DMF)为溶剂,基于静电纺丝技术制备聚偏氟乙烯(PVDF)纳米纤维膜,与聚丙烯(PP)熔喷基布覆合,制备PVDF/PP纳/微米复合纤维膜。实验研究静电纺丝工艺参数对复合结构纤维膜气溶胶过滤性能的影响规律。建立三元二次多项式模型优化纺丝工艺,同时构建反向传播(BP)神经网络模型,预测不同工艺下的纤维膜过滤阻力。结果表明,电压、接收距离、注射速度、纺丝液浓度和纤维膜面密度对过滤效率和过滤阻力有着一致的影响规律。纺丝液浓度为15wt%、面密度为3 g/m2时,优化纺丝工艺参数为:电压30 kV,接收距离16.8 cm,注射速度1.6 mL/h。应用多项式模型预测的过滤阻力值为76.79 Pa,相对误差为9.23%,误差变异系数(CV)值为59%。BP神经网络预测的过滤阻力值为81.25 Pa,相对误差为1.99%,误差CV值为48%。实验证明,三元二次模型和BP神经网络具有较高的预测准确度。

     

    Abstract: Mask was an important epidemic prevention barrier to prevent virus from entering human body through respiratory system and mucous membrane. The disposable mask had some problems, such as rapid decline of filtration efficiency with electrostatic attenuation, large respiratory resistance, short service life and so on. Electrospun nanofiber membrane was compounded with melt blown cloth to reduce the dependence of particle filtration on static electricity and realize long-term filtration. Polyvinylidene fluoride (PVDF) nanofiber membrane was prepared by electrospinning with N, N-dimethylformamide (DMF) as solvent. Then it was coated with polypropylene (PP) melt blown base cloth to prepare PVDF/PP nano/micron structure composite fiber membrane. The effect of electrospinning process parameters on the aerosol filtration performance of composite fiber membrane was experimentally studied. The ternary quadratic polynomial model was established to optimize the spinning process and predict the fiber membrane resistance. At the same time, the back propagation (BP) neural network model was constructed to predict the fiber membrane resistance. The results show that the effects of voltage, receiving distance, injection speed, spinning solution concentration and fiber membrane surface density on the filtration efficiency and filtration resistance are consistent. When the concentration of spinning solution is 15wt% and the area density is 3 g/m2, the optimized spinning process parameters are voltage of 30 kV, receiving distance of 16.8 cm and injection speed of 1.6 mL/h. The filtration resistance predicted by polynomial model is 76.79 Pa, the relative error is 9.23%, and the error coefficient of variation (CV) value is 59%. The filtration resistance predicted by BP neural network is 81.25 Pa, the relative error is 1.99%, and the error CV value is 48%. The experiments show that the ternary quadratic model and BP neural network have high prediction accuracy.

     

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