Study of the crystallinity effect of mechanical properties of thermoplastic composites with aeronautical application

Abstract

Advanced polymeric composites have been standing out in the aerospace industry due to a favorable combination of low specific mass and high mechanical performance. Most of the advanced polymeric composites currently used are obtained from reinforced thermosetting resins; however, this material presents stress problems due to processing and the brittle nature of the resin. Thermoplastic polymers reinforced with continuous fibers are a great replacement when compared with conventional thermosetting polymers, due to advantages such as: higher values of rigidity and impact resistance, higher service temperature and wider versatility in series production. The aim of this work is to process thermoplastic composites with carbon fibers with different degrees of crystallinity and evaluate its influence on mechanical performance (vibration, compression and shear) and thermal performance (thermal dilatation coefficient by TMA and DMTA), involving different environmental conditionings (hygrothermal, UV and saline mist). The development of this project will count with the available structure at FEG UNESP, which is equipped with laboratories of mechanical testing, environmental conditioning, thermal analysis and processing of composites, all funded by FAPESP from the projects nr 2005/54358-7 (Influence of Hygrothermal Conditioning on Mechanical Properties of Composites with Aeronautical Applications), nr 2008/00171-1 (Evaluation of Crystallization and Curing Kinetics of Matrices used in Advanced Composites) and the project nr 2011/09062-3 (Evaluation of Mechanical and Thermal Performance of Aeronautical Thermoplastic Composites with Different Degrees of Crystallinity). During the execution of this work, composites constituted of carbon fibers agglutinated with PPS (polyphenylene sulphide) matrix and/or PEEK (polyetheretherketone) matrix will be processed. These matrices will be characterized by differential scanning calorimetry (DSC) and thermogravimetry (TG). The results obtained from these analyses will support the choice of the most suitable processing conditions for these thermoplastic laminates. After processed, these laminates will characterized by the previously mentioned testing. (AU)