An Analysis of Interfacial Adhesion Between TPU/MWCNT Composites and ABS Substrate by Over Injection Molding

In this work, the advantages of Thermoplastic Polyurethane (TPU) filled with multi-walled carbon nanotubes (MWCNTs) were combined with those of the over injection molding process in order to obtain two-component (2k) structures with very different but high mechanical and electrical properties. TPU/MWCNT composites with different MWCNTs wt.% were over-molded onto Acrylonitrile Butadiene Styrene (ABS) substrates, under different processing conditions, and the adhesion was assessed by T-peel tests at room temperature. Since adhesion is also related to flow behavior, the rheological properties were studied with a capillary rheometer at shear rates similar to those of the injection molding process (10²∼10⁴s⁻¹). Experimental results indicated that the most effective way to control the adhesion between the ABS substrate and the over-molded TPU/MWCNT composite is to increase the melt temperature. The addition of carbon nanotubes improves adhesion in the vicinity of 0.5 wt.% MWCNTs.