Toughening of epoxy matrix fiber reinforced composites with two different nanorubber systems for Advanced Industrial Applications

N.G. Ozdemir, Tao Zhang
Kingston University London, UK

Keywords: acrylonitrile butadiene rubber, carboxylated acrylonitrile butadiene rubber, nanoparticle, toughening, epoxy resin


Toughening of commercial resin matrices with nano carboxylated acrylonitrile butadiene rubber (CNBR-NP) and acrylonitrile butadiene rubber (NBR-NP) was investigated. Different processing techniques have been used. The rheological, cure, mechanical and morphological characteristics of both systems at different dispersions and loadings have been analyzed. Mechanical properties of toughened resin matrices only and the carbon fiber reinforced laminates processed with the toughened matrices have been studied. SEM images showed that CNBR-NP has been dispersed evenly and in nano dimension within the matrix whereas high amount of agglomeration within NBR-NP system caused plasticization of the matrix however still increased the G1c for 250%. Achievement of even and nano-size dispersion of CNBR-NP dramatically improved the Mode I fracture toughness of carbon fiber laminates for 250%, G2C for 200% and the glass transition temperature stayed the same with addition of 20 phr of rubber to the epoxy. Morphological characterization of the fracture surfaces with SEM showed that toughening was mainly achieved through cavitation formation, shear banding and crack path deflection for both rubber systems. Difference in dispersion efficiency of nanorubbers within epoxy has been related to the difference in Van der Waals forces between single particles, the size effect and the polarity of the systems.