Innovative Plasma Process of Grafting Methyl Diallyl Ammonium Salt onto Polypropylene to Impart Antibacterial and Hydrophilic Surface Properties

A conventional plasma grafting (PG) process for surface treatment has limitations; thus, it should be modified to boost its efficiency. In this study, a new process called immersion–pad-pressing–drying–plasma (IPDP) was proposed. We applied IPDP to graft a quaternary methyl diallyl ammonium salt on the surface of a polypropylene (PP) nonwoven. Ar and O2 were used as carrier gases for the plasma treatment. For this IPDP process, the optimum acid catalyst concentration was established to be 0.2 M. The grafted PP exhibited excellent antibacterial and hydrophilic properties. Because of the introduction of more peroxides or carboxylic acid groups into the PP nonwoven, the graft ratio for the PG and IPDP processes with O2 as the carrier gas was demonstrated to be higher than that for the processes with Ar as the carrier gas. The finished PP fabric obtained using the IPDP process indicated antibacterial and hydrophilic properties superior to those of the fabric obtained from the traditional PG process. The IPDP process could overcome the disadvantages of the conventional plasma process, one of which is that the PG process requires a long period of time to bring a grafting reaction to completion. This new IPDP process is shown to be an efficient technique for industrial applications.