双光栅监测环氧树脂固化过程及玻璃化温度实验

为了实时监测环氧树脂的固化过程,建立了基于 光纤布拉格光栅(FBG)的固化监测系统。将裸FBG、石英毛细管封装FBG和高精度热 电阻浸入到环氧树脂及其固化剂的混合物中,一 起经历固化过 程。在升降温过程中,用热电阻监测环氧树脂内部温度变化,用波长解调仪实时测量两种FB G的波长变化。 实验结果表明,石英毛细管封装FBG监测到的温度变化趋势与热电阻监测结果相同；两种FBG 的波长差反 映了固化过程中的收缩应变,固化初期变化较大,之后逐渐减小。以玻璃态转变温度为分界 点,直接植入 环氧树脂的FBG温度灵敏度分别为石英毛细管封装FBG的5.3倍和为2.2倍。

Cure monitoring and glass transition temperature measuring of epoxy resin using two FBGs

In order to monitor curing process of epoxy resin in real time,the system based on fiber Bragg grating (FBG) is established .A bare FBG,a FBG packaged with quar tz capillary and an accurate resistance thermometer are immersed into the mixtur e of epoxy resin and curing agent,and are used to monitor the whole curing process.The change of temperature inside epoxy resin is det ected by the resistance thermometer. Meanwhile,the reflection wavelengths of two fiber Bragg gratings are measured by the spectrum analyzer. Experimental results indicate that the temperature evolution monitored by the FB G packaged with quartz capillary is the same as that measured by the resistance thermometer.D uring curing process,inner strain changes of epoxy resin can be taken in by the variation of wavelength difference between FBGs.At the beginning of polymerization reaction,the strain inside epoxy resin quickly increases,and then gradually tend s to a constant value.The temperature sensitivity of the FBG embedded with epoxy resin is 5.3times of tha t of the FBG packaged with quartz capillary when temperature is lower than the glass transition temperature,and 2.2times wh en temperature is higher than the glass transition temperature.