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Poly(lactide) (PLA) and poly(methyl methacrylate) (PMMA) are melt compounded with chopped glass fiber using laboratory scale twin‐screw extrusion. Physical properties are examined using differential scanning calorimetry (DSC), dynamic mechanical thermal analysis (DMTA), thermogravimetric analysis (TGA), tensile testing, impact testing, X‐ray computed tomography (CT) scanning, and field emission scanning electron microscopy (FE‐SEM). Molecular weight is determined using gel permeation chromatography (GPC). Miscibility of the blends is implied by the presence of a single glass transition temperature and homogeneous morphology. PLA/PMMA blends tend to show positive deviations from a simple linear mixing rule in their mechanical properties (e.g., tensile toughness, modulus, and stress at break). The addition of 40 wt % glass fiber to the system dramatically increases physical properties. Across all blend compositions, the tensile modulus increases from roughly 3 GPa to roughly 10 GPa. Estimated heat distortion temperatures (HDTs) are also greatly enhanced; the pure PLA sample HDT increases from 75 °C to 135 °C. Fiber filled polymer blends represent a sustainable class of earth abundant materials which should prove useful across a range of applications. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017, 134, 44868.

Currently, wind turbine blades are manufactured from a combination of glass and/or carbon fiber composite materials with a thermoset resin such as epoxy, which requires energy-intensive and expensive heating processes to cure. Newly developed in-situ polymerizing thermoplastic resin systems for composite wind turbine blades polymerize at room temperature, eliminating the heating process and significantly reducing the blade manufacturing cycle time and embodied energy, which in turn reduces costs. Thermoplastic materials can also be thermally welded, eliminating the need for adhesive bonds between blade components and increasing the overall strength and reliability of the blades. As well, thermoplastic materials enable end-oflife blade recycling by reheating and decomposing the materials, which is a limitation of existing blade technology. This paper presents a manufacturing demonstration for a 9-m-long thermoplastic composite wind turbine blade. This blade was constructed in the Composites Manufacturing Education and Technology facility at the National Wind Technology Center at the National Renewable Energy Laboratory (NREL) using a vacuumassisted resin transfer molding process. Johns Manville fiberglass and an Arkema thermoplastic resin called Elium were used. Additional materials included Armacellrecycled polyethylene terephthalate foam from Creative Foam and low-cost carbonfiber pultruded spar caps (manufactured in collaboration with NREL, Oak Ridge National Laboratory, Huntsman, Strongwell, and Chomarat). This paper highlights the development of the thermoplastic resin formulations, including an additive designed to control the peak exothermic temperatures. Infusion and cure times of less than 3 hours are also demonstrated, highlighting the efficiency and energy savings associated with manufacturing thermoplastic composite blades.

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This test project could not have occurred without the partnership between the National Renewable Energy Laboratory (NREL) and Mitsubishi Heavy Industries (MHI). MHI's technical points of contact, Takao Kuroiwa and Hiroyuki Kayama supported this test project. The NREL authors greatly appreciate the trust instilled in NREL through the use of an MHI wind turbine rotor blade to demonstrate this innovative test method. The work described in this report would not have been possible without the exceptional structural blade test team at the National Wind Technology Center. The key NREL staff members working on this project included Ryan Beach, Michael Desmond, Bill Gage, Mike Jenks, and Nathan Post. Post's help with test simulations and tuning ensured that the test was commissioned on schedule. Beach, Gage, and Jenks were the primary individuals responsible for the test system assembly, maintenance, and daily operation. Desmond provided critical expertise throughout the data postprocessing phase. The MTS Systems Corporation (MTS) team was instrumental in the control system development required to commission this complicated test system. Phil Berling led the effort at MTS to pull together the necessary technical experts for this challenging project. Charlie Anderson was the MTS architect behind the biaxial resonant tracking algorithm that was successfully implemented during this test. Pat Morton of MTS supplied test simulation expertise and suggested the coordinate system transformation technique used for test control.

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In accordance with Requirements set forth in Article XI.A(3) of the CRADA document, this document is the final CRADA report, including a list of Subject Inventions, to be forwarded to the Office of Science and Technical Information as part of the commitment to the public to demonstrate results of federally funded research.