Plasma treatment to improve the adhesion between ABS and PA6 in hybrid structures produced by injection overmolding

Abstract

In this article, we investigate the possibility of combining ABS and PA6 in one structure by means of injection overmolding. The combination of these polymers in one structure is very promising, as PA6 offers good mechanical performance and high melting temperature and abrasion resistance. In contrast, ABS offers excellent impact properties, high water resistance, and cost competitiveness. However, these polymers are incompatible and do not adhere to each other. This study proposes atmospheric plasma treatment to create bonding between ABS and PA6 processed by injection molding. We demonstrated that bonding was created between ABS and PA6 due to the hydroxylation and the chemical conversion of nitrile groups to amide and carboxyl acid after the plasma treatment of ABS. Therefore, the plasma-treated ABS surface enabled the formation of various H-bonds, and the strong coupling of ABS and PA6 via secondary chemical binding forces appears. These results were also proved by mechanical tests, which showed that the bonding strength of the ABS/PA6 material pair reaches 12 MPa after plasma treatment, while an untreated case demonstrated no bonding at all.