Lu Shaowei, Zhao Chenxu, Zhang Lu, Chen Duo, Chen Dandan, Wang Xiaoqiang, Ma Keming
Faculty of Aerospace Engineering, Shenyang Aerospace University Shenyang Liaoning 110136 China
RSC Adv. 2018 Jun 15;8(39):22078-22085. doi: 10.1039/c8ra03445a. eCollection 2018 Jun 13.
This paper proposes a flexible and highly sensitive carbon nanotube buckypaper as a sensing layer embedded within a composite for cure monitoring applications. The buckypaper was fabricated with mono-dispersion of multi-wall carbon nanotubes by a spray-vacuum filtration method. Six different curing conditions (with maximum heating temperatures of 120 °C, 108 °C, 95 °C, 90 °C, 85 °C and 75 °C) were designed to characterize and analyze the electromechanical response of the BP sensor to the composite structure, and the results indicated that the temperature coefficient of resistance of buckypaper is associated to the resin curing behavior. The critical value (-7.18 × 10 °C) of the temperature coefficient of resistance was determined. Experimental results also show that a stable three-dimensional network of resin molecular chains is formed and that the polymer presents a glassy state when the value of the temperature coefficient of resistance is greater than the critical value. Based on this relationship, a hypothesis was raised that for the complete curing of the resin, the temperature coefficient of resistance of the buckypaper sensor should meet the critical value condition, which was also consistent with the differential scanning calorimetry testing of the curing degree. The buckypaper sensor was found to be sensitive to the curing degree of the resin, and has a promising future in applications in composite manufacturing processes. Moreover, the properties of composite components are indeed able to be improved the monitoring and optimization of the curing parameters.
本文提出了一种柔性且高灵敏度的碳纳米管巴基纸作为嵌入复合材料中的传感层，用于固化监测应用。通过喷雾 - 真空过滤法，利用多壁碳纳米管的单分散体制备了巴基纸。设计了六种不同的固化条件（最高加热温度分别为120°C、108°C、95°C、90°C、85°C和75°C）来表征和分析BP传感器对复合材料结构的机电响应，结果表明巴基纸的电阻温度系数与树脂固化行为相关。确定了电阻温度系数的临界值（-7.18×10°C）。实验结果还表明，当电阻温度系数的值大于临界值时，会形成稳定的树脂分子链三维网络，且聚合物呈现玻璃态。基于这种关系，提出了一个假设，即对于树脂的完全固化，巴基纸传感器的电阻温度系数应满足临界值条件，这也与固化度的差示扫描量热法测试结果一致。发现巴基纸传感器对树脂的固化度敏感，在复合材料制造过程中的应用具有广阔前景。此外，通过对固化参数的监测和优化，确实能够改善复合材料部件的性能。
