Thermal Analysis of Thermoplastic Resins in the Manufacture of Tidal Turbine Blades

Tidal turbine blades are constantly subjected to challenging operating conditions, requiring thick sections (10 - 100 mm) to withstand high load requirements. Typically constructed from thermoset-matrix composite materials using vacuum infusion production, the rising use of polymer composite materials highlights the need for recyclable alternatives. This work experimentally analyses the thermal profiles of Elium<sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">®</sup>188 XO, a liquid thermoplastic resin, undergoing polymerisation in the manufacture of thick-section laminates at three different thicknesses of 10-ply, 20-ply and 30-ply, measuring approximately 8 mm, 16 mm and 24 mm after polymerisation. Five thermocouples positioned through the height of each laminate sampled data for twelve hours to include infusion, polymerisation and ending at demoulding. Manufacturing defects such as trapped air, residual stresses from large temperature differences between plies and differences in extent of cure can impact the quality and properties of thick laminates. The maximum temperatures in the 10-, 20- and 30-ply laminates were found to be 86.50°C, 92.61°C and 93.94°C, indicating that interlaminar temperature increases with layup thickness. Temperatures in all three laminates stayed below the resin's boiling point (approximately 100°C). Exceeding this temperature would cause air bubbles, leading to voids and defects. Results and insights from these trials will further knowledge of the polymerisation behaviour of alternative liquid thermoplastic resins in the production of thick-section laminates, which is key in validating their applicability in the manufacture of tidal turbine blades.