Advanced thermoplastic composites for wind turbine blade manufacturing

Abstract

Fiber-reinforced polymer composites are an intriguing class of engineering materials that are increasingly exploited in the construction, aerospace, and energy sectors. Their high specific properties make them an ideal design choice where traditional engineering materials like metals are too heavy, or where unreinforced polymers are not stiff or strong enough. Furthermore, their anisotropic nature can be exploited for unique applications such as airfoils in aircraft wings or wind turbines. However, most structural composites use thermosetting polymers as their matrix, which presents several issues. Foremost is that thermosets cannot be easily recycled, so massive amounts of composite waste are landfilled at the end of a part’s service life. Secondly, thermoset subcomponents of a larger structure can only be joined using adhesives. Conversely, thermoplastic composites enable recycling after a part is retired from service and facilitate thermal joining of multi-part structures. Liquid infusible thermoplastic resins are beginning to emerge for use in vacuum-assisted resin transfer molding, which is the method of manufacture for wind turbine blades. While infusible thermosetting resins have been well characterized, basic characterization of rheological and kinetic behavior for thermoplastic resins is lacking. The present work provides important experimental development and data aimed at characterization of infusible thermoplastic resin systems. A novel thermoplastic biobased resin system is also developed, which has potential for commercial use.