In-situ monitoring of cross-linking reactions using E-glass fibres and evanescent wave spectroscopy

Abstract

a b s t r a c t E-glass fibres are used in products such as printed circuit boards, wind turbine blades, pipes, marine vehicles and pressure vessels. With reference to the production of fibre reinforced composites, the reinforcement (E-glass) is impregnated with a resin system, consolidated and generally processed by the application of heat. This results in the resin system being converted from a liquid or semi-solid to a highly cross-linked and infusible solid. There is significant interest in monitoring the progression of these crosslinking or chemical reactions and a number of optical and electrical, ultrasonic-based techniques have been developed and demonstrated. The current paper reports on the use of the reinforcing E-glass fibres to track the cross-linking of commercially available epoxy/amine resin systems. The mode of interrogation was based on using the E-glass fibres as evanescent wave sensors thus enabling Fourier transform infrared spectroscopy to be conducted. This enabled the cross-linking reactions at the glass/resin interface to be monitored. Conventional transmission Fourier transform infrared spectroscopy experiments were also conducted. The cross-linking kinetic data from the two methods were modelled and compared. A good correlation was obtained between the experimental and predicted data using a single rate constant.

Near‐Field Optical Excitations in Silicon Subwavelength Light Funnel Arrays for Broadband Absorption of the Solar Radiation

“…For example, the critical angle for the silicon/ambient interface for λ = 500 nm is 13.4°, and the penetration depth at a slightly higher incident angle of 14° is almost 570 nm which is greater than the distance between the bottom parts of closest neighbors LFs in a P = 500 nm array. [ 38 ]…”

Analysis of the Light Transmission Ability of Reinforcing Glass Fibers Used in Polymer Composites

“…It means that the transmitted optical power of the fibers is affected by the temperature. This can be utilized to monitor the temperature, or the in situ curing process during the manufacturing of the composite part [ 22 , 23 ]. Further investigation is needed to find out the effect of temperature on the transmitted optical power.…”

Towards self-diagnosis composites: Detection of moisture diffusion through epoxy by embedded evanescent wave optical fibre sensors

“…L. Wang et al [13] monitored the cross-linking reaction during GFRPs fabrication, where the E-glass fibres that constitute the composite were directly used as a light transmission bundle and sensor.…”