Lignin as Sustainable Antimicrobial Fillers to Develop PET Multifilaments by Melting Process

Nowadays, textiles functionalization is developing increasingly, fabrics are not only defined by the intrinsic properties of the fiber but some properties are also brought to provide them added value. Among the desired properties, antibacterial activity is targeted to improve the comfort and durability of textiles but many commercial products use chemical substances which are harmful for the environment (regulation 528/2012). The goal of this study was to use bio-based biocide which can be incorporated in the polyethylene terephthalate (PET) by melt spinning for the development of functional PET. This biocide had to resist to the PET processing temperature up to 264°C which was the maximum temperature of implementation. Two kinds of Kraft lignin and titanium dioxide as reference were added by melting way. The antimicrobial activity was characterized at low concentration (1 and 2 wt.%), to avoid a significant decrease in mechanical strength for the multifilaments and to maintain optimal rheological properties of the polymer for the melt spinning process. Filled PET pellets were obtained by twin screw extrusion step and the multifilaments by melt spinning step. Finally, knitting structures were developed for the evaluation of the antibacterial activity. The mechanical (tensile test) and thermal (DSC and TGA) properties of the filaments were characterized.