Effects of Styrene-Acrylic Sizing on the Mechanical Properties of Carbon Fiber Thermoplastic Towpregs and Their Composites

• Published in: Molecules (Basel, Switzerland) Vol. 23; no. 3; p. 547
• Main Authors: Bowman, Sean, Jiang, Qiuran, Memon, Hafeezullah, Qiu, Yiping, Liu, Wanshuang, Wei, Yi
• Format: Journal Article
• Language: English
• Published: Switzerland MDPI AG 01.03.2018; MDPI
• Subjects: Calorimetry; Carbon fiber reinforced plastics; carbon fiber-thermoplastic composites; Carbon fibers; carbon-fiber tows; Coating effects; Compression; Compressive strength; Continuous fiber composites; Differential scanning calorimetry; Fabrication; Fiber composites; Fiber reinforced polymers; High temperature; Hot pressing; Interfacial shear strength; Mechanical properties; Modulus of rupture in bending; Organic chemistry; Polymer matrix composites; Powder; Preforming; Pressure molding; Protective coatings; Raw materials; Rigidity; Sizing; Styrene; styrene-acrylic sizing; Styrenes; Tensile tests; Thermal stability; towpregs; carbon-fiber tows; carbon fiber-thermoplastic composites; styrene-acrylic sizing; towpregs
• ISSN: 1420-3049; 1420-3049
• DOI: 10.3390/molecules23030547

Thermoplastic towpregs are convenient and scalable raw materials for the fabrication of continuous fiber-reinforced thermoplastic matrix composites. In this paper, the potential to employ epoxy and styrene-acrylic sizing agents was evaluated for the making of carbon fiber thermoplastic towpregs via a powder-coating method. The protective effects and thermal stability of these sizing agents were investigated by single fiber tensile test and differential scanning calorimetry (DSC) measurement. The results indicate that the epoxy sizing agent provides better protection to carbon fibers, but it cannot be used for thermoplastic towpreg processing due to its poor chemical stability at high temperature. The bending rigidity of the tows and towpregs with two styrene-acrylic sizing agents was measured by cantilever and Kawabata methods. The styrene-acrylic sized towpregs show low torque values, and are suitable for further processing, such as weaving, preforming, and winding. Finally, composite panels were fabricated directly from the towpregs by hot compression molding. Both of the composite panels show superior flexural strength (>400 MPa), flexural modulus (>63 GPa), and interlaminar shear strength (>27 MPa), indicating the applicability of these two styrene-acrylic sizing agents for carbon fiber thermoplastic towpregs.