New High-Performance Fibre Reinforced Materials With Nanocomposites

Abstract

Injection techniques are well established for production of high-performance fibre composites due to their cost advantages in comparison to the Prepreg method. However, the properties of high performance composites produced using the injection technique have not yet reached the level of the Pre-preg composites. Among other factors this is due to matrix shrinkage, which leads to intrinsic tension within the part and thereby reduces the material performance. At the DLR Institute for Structural Mechanics, a new innovative method was selected for compensating the previous material disadvantages of the injection technique. With the single line injection method (SLI), developed at this institute, the composite qualities are optimised by using nanocomposites. It has been shown on the basis of selected nanoparticle systems, that the thermal and mechanical performance parameters of tested epoxy resins can be improved specifically even at very low particle content. Considered in detail, a high-performance epoxy resin is modified with nanoscaled barium sulphate. This is distinguished by a significantly higher impact strength and strain at break in comparison to unmodified resin without reducing any other composite parameters. Transfer of the high ductility of the polymeric matrix to fibre reinforced compos-ites might compensate the material disadvantages from matrix shrinkage, normally resulting for fibre composites produced using the injection technique. Accordingly, the material disadvantages of the injec-tion technique compared to the Prepreg technique can be compensated and the problems of the injection technique appear to be solved. Moreover, initial results with fibre-reinforced composites (GFRP) are in-troduced, which are filled with nanoscaled silicon dioxide particles and produced using the SLI technique. Particularly the significant increase of the Young’s modulus and its high linearity in the stress-strain diagram leads to reduction of the inter-fibre fractures and improvement of the material perform-ance in comparison to unfilled fibre composite. The larger damage-free range for the new type of fibre composites opens new fields of application and increases the application potential for SLI technique.