Publications by authors named "K J Rager"
Article Synopsis
- Observing the curing reaction of epoxy resins is crucial for ensuring quality in fibre composite production, with electrical impedance spectra being a key monitoring method.
- Impedance spectra reveal physical changes during curing: early stages are dominated by ionic conductivity and electrode polarization, while dipole relaxation takes over later; evaluating across an entire frequency spectrum is more effective than focusing on a single frequency.
- A proposed frequency-dependent model simplifies the interpretation of complex raw spectral data, achieving a relative error of only 2.3% with five parameters, while indicating the need for changing key indicators as the curing process progresses.
Numerous synthetic techniques for the fabrication of porous metal electrodes were developed in recent decades. A very promising and facile route is the 3D printing of structures, which can be designed directly on the computer first. However, the current techniques allow structures to be printed with a resolution down to 20 µm, which is still quite rough regarding tuning the pore distribution and diameter of electrode materials for potential applications.
View Article and Find Full Text PDFThe ability to measure the degree of cure of epoxy resins is an important prerequisite for making manufacturing processes for fibre-reinforced plastics controllable. Since a number of physical properties change during the curing reaction of epoxy resins, a wide variety of measurement methods exist. In this article, different methods for cure monitoring of epoxy resins are applied to a room-temperature curing epoxy resin and then directly compared.
View Article and Find Full Text PDFMonitoring process parameters in the manufacture of composite structures is key to ensuring product quality and safety. Ideally, this can be done by sensors that are embedded during production and can remain as devices to monitor structural health. Extremely thin foil-based sensors weaken the finished workpiece very little.
View Article and Find Full Text PDFArticle Synopsis
- The study investigates how well different thermoplastic films adhere to a room temperature-curing epoxy resin, which is crucial for integrating sensors into fibre composites.
- The research uses a morphological box to create test specimens and evaluates adhesion strength among polyimide (PI), polyetherimide (PEI), polyethersulfone (PES), and polyamide 6 (PA6).
- Results show that PEI has unexpectedly high adhesion strength (70 MPa) despite low interphase formation, while PES exhibits the lowest (5 MPa), indicating that PEI is preferable for sensor applications where delamination is a concern.