Enhancing the marine antifouling property of high-density polyethylene through melt grafting of poly (hexamethylene guanidine)

Acquiring environment-friendly, wide-spectrum antifouling materials is currently a significant challenge. Herein, we focused on covalently bonding poly (hexamethylene guanidine) (PHMG) to high-density polyethylene (HDPE) through a melt grafting reaction. The successful occurrence of this grafting reaction was confirmed by FT-IR analysis. Moreover, the presence of long-chain branching (LCB) was established through Cole-Cole plot, van Gurp-Palmen diagram, and dynamic thermomechanical property. This presence of LCB improved the impact strength of modified HDPE materials. An increased PHMG grafting content in the material led to a significant increase in the inhibition rate of Escherichia coli and Staphylococcus aureus growth, without any detectable leaching of PHMG. Furthermore, inverted fluorescence microscopy revealed a substantial inhibitory effect of the modified HDPE on diatom attachment and Chlorella sedimentation. Specifically, compared with the unmodified HDPE material, the HDPE with 2 wt% PHMG grafting showed a 79.8% decrease in the attachment rate of diatoms and a 64.5% reduction in Chlorella sedimentation. This research provides valuable insights into the development of eco-friendly antifouling materials with enhanced marine antifouling properties.