Fabrication and characterization of vapor grown carbon nanofiber reinforced flexible polymer composites

In this study, highly flexible polymer nanocomposites that can be stretched more than 9 times their original length were successfully fabricated by using poly [styrene-b-(ethylene-co-butylene)-b-styrene] (SEBS) and vapor grown carbon nanofibers (VGCNFs). Two different polymers were used in order to investigate the effects of the polymer molecular weight on viscosity, morphological and mechanical properties of the samples. Mixing was carried out by a planetary high shear mixer for various levels of VGCNFs and SEBS. Nanocomposites were prepared by the combination of solvent casting and compression molding. Viscosity measurements were carried out as a function of filler ratio for both polymers. Higher molecular weight and higher filler ratio led to higher viscosity. Morphological analysis showed homogeneous filler dispersion without any dominant filler orientation throughout the composites with good filler-matrix interface and absence of any pores or voids. Filler content and matrix molecular weight were found significant for mechanical properties. The mechanical strength and elastic modulus of the nanocomposites increased by the addition of VGCNF regardless of the polymer molecular weight. Nanocomposites fabricated by using higher molecular weight polymer showed better mechanical properties. Above mentioned attributes those belong to both polymer composites meet the requirements of flexible electronics and can be used for many applications including micro-electro-mechanical systems, conductive coatings, electromagnetic shielding applications, polymeric sensors and actuators.