Mechanical and structural studies on single point incremental forming of polypropylene-MWCNTs composite sheets

Polypropylene-based composites filled with different amounts of functionalized multi-wall carbon nanotubes (f-MVVCNTs) were prepared using a melt mixing process, and were shaped by single point incremental forming process (SPIF). The performance of these composite materials when processed by SPIF indicated that the presence of small quantities (<1 wt%) of f-MWCNTs leads to a mechanical reinforcement of the polymer matrix, without affecting its formability. This reinforcement was further highlighted due to the alignment of the polymer chains and nanotubes caused by the forming process. A variation in color between the inner and outer sides of the deformed parts revealed the presence of crazing, associated to the different forces exerted on each side. The dispersion of the f-MWCNTs and the polymer-nanotube interaction in the composites were studied by different characterization techniques, and it was found that a good integration of the f-MWCNTs into the polymer matrix was achieved. (C) 2016 Elsevier B.V. All rights reserved.