Abstract
The mechanical properties of continuous fiber-reinforced thermoplastic (C-FRTP) composites are commonly lower than those of continuous fiber-reinforced thermosetting plastic (C-FRP) composites. We have developed a new molding method for C-FRTP. In this study, pre-impregnated materials were successfully prepared by polymer solution impregnation method and, finally, C-FRTP was fabricated. The viscosity of the thermoplastic matrix was decreased to approximately 3dPa×s, the same level of epoxy, and the fiber volume fraction was increased from approximately 45 to 60%. The cross-section of specimens were polished by an ion milling system and impregnation condition was investigated by scanning electron microscopy (SEM). The micrographs suggested that thermoplastic polymer was impregnated to every corner of the fiber, and no void was found on the cross-section. It revealed that void-free composites with perfect mechanical properties can be manufactured with this new molding method. All specimens were submitted to a mechanical measuring equipment, and the mechanical properties of the composite specimens were investigated. Mechanical analysis revealed that tensile property and flexural property of C-FRTP were enhanced up to the same level with C-FRP.
Highlights
Fiber-reinforced plastic (FRP), a composite material made of a polymer matrix reinforced with fibers, has been widely used in various industries for their high specific strength and stiffness, such as automobiles, aeroplanes, watercrafts, windmill blades, tennis rackets and so on
It is very difficult to fabricate continuous fiber-reinforced thermoplastic with the current major technologies, e.g., injection molding which was developed for manufacturing short fiber-reinforced thermoplastic (S-FRTP), and vacuum assistant resin transfer molding (VaRTM), for continuous fiber-reinforced thermosetting plastic (C-FRP)
High viscosity leads to low mechanical properties because it is hard for high viscosity polymer matrix to impregnate fiber completely, with abundant bubbles and polymer-matrix-free regions forming in final FRP composites
Summary
Fiber-reinforced plastic (FRP), a composite material made of a polymer matrix reinforced with fibers, has been widely used in various industries for their high specific strength and stiffness, such as automobiles, aeroplanes, watercrafts, windmill blades, tennis rackets and so on. It is very difficult to fabricate continuous fiber-reinforced thermoplastic with the current major technologies, e.g., injection molding which was developed for manufacturing short fiber-reinforced thermoplastic (S-FRTP), and vacuum assistant resin transfer molding (VaRTM), for C-FRP. One is as close to the fiber and thermoplastic polymer matrix as possible before the final step in composite fabrication, such as powder impregnation, commingled yarn, co-woven fabric, film-stacking method technologies, to reduce void; the other is to synthesise the thermoplastic polymer matrix directly, such as in situ polymerization, to reduce viscosity [5]. The present work reports that a facile method was developed to achieve low viscosity thermoplastic matrix so that the impregnation was improved, and fiber volume fraction was increased in final C-FRTP composites [31]. A convenient process of producing pre-impregnated material by polymer solution impregnation method is proposed
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
