Processing and characterization of amorphous polyethylene terephthalate fibers for the alignment of carbon nanofillers in thermosetting resins

The engineering aspects associated with the development of nanocomposites involve either their final properties either their processability. Both are affected by the distribution of nanofiller in the matrix and by the aspect ratio of the nanofiller. A nanofilled thermosetting resin can be exploited as a matrix for continuous fibers when the alignment of a high aspect ratio nanofiller is achieved: in this case a hierarchical composite is obtained. A new procedure for the alignment of nanofillers in a thermosetting matrix is proposed in this study. The two-step approach is based on i) the alignment of nanofillers (carbon nanotubes, graphene, ect.) in thermoplastic fibers by a fiber spinning processes and ii) use of these nanocomposite fibers as a carrier to bring aligned nanofillers into a reactive thermosetting resin. These fibers, soluble in the thermosetting resin, release the nanofillers orientated according to the direction in which fibers are positioned, even after the matrix curing. The proof of concept is demonstrated by producing melt spun polyetylene terephtalate (PETg) fibers filled with graphene nanoplatelets (GNP) and multi-wall carbon nanotubes (MWCNT) with a very high filler content (up to 10 wt%) in view of producing a hierarchical composite