UV-LED Curable Glass Fiber Composites and their Properties
Using UV Energy to cure composites has a number of advantages when compared to curing composites with thermal energy. The primary advantage is with increased productivity due to the inherently rapid speed of reaction that occurs with UV curing. Parts can be cured in a few minutes or sometimes in a few seconds using UV chemistry. The second advantage is “cure on demand”. Since a UV curable system will not react unless it is illuminated with UV energy, very long pot lives are achievable and the cure process only takes place when the operator wants it to. This also means that resin that has not been exposed to UV energy can be collected and re-used, cutting down on waste.
Traditionally, mercury lamps have been used to provide the UV energy for curing. More recently, UV-LED has been introduced. UV-LED is more sustainable (lower energy use, mercury free) and does not have the thermal output of mercury lamps. The UV-LED energy is confined to a relatively narrow wavelength band so formulating for UV-LED cure can be challenging.
We will demonstrate some formulation techniques for getting good surface and through cure using UV-LED vs. mercury lamps and compare cure speed, double bond conversion, depth of cure and part temperature vs. time for both cure processes. The properties, such as Tg and flexural modulus, of both the unfilled resin matrix and composite systems cured with UV-LED and mercury lamps will also be presented.
Moderate (Working Knowledge of Technical Content)