Innovative, protective plastics against microorganisms Antimicrobial agents in plastics are widely sought, yet commercialisation of such compounds is still very limited. To answer this need, the SPAN project produced novel specialty polymeric materials displaying unique antimicrobial and/or antifouling properties. Industrial Technologies © DigitalVision The antibacterial properties of most conventional products highly depend on tiny bacteriostatic molecules that are mixed with the polymeric matrix. However, this sort of synthesis approach displays a few shortcomings in the control of certain parameters, such as uniformity in dispersion, migration rate and leaching. Unlike these materials, the novel antibacterial compounds constitute part of the polymer itself as they involve active groups on the backbone of the polymer chain. Additionally, provision has been made for increased environmental friendliness, since the materials are free of chlorine and/or heavy metals. More specifically, polymeric blends with antimicrobial and/or antifouling properties have resulted from dispersion of the active phosphonium salt-containing oligomers or polymers into a polymeric matrix. The polymeric matrices may be polyethylene, polypropylene or polyamides and the proportion of the active compound falls within the range of 1-10%. Characterisation of the polymeric blends according to their mechanical and thermal properties was also made. Aided by specialised screening techniques the high-density polyethylene blend was found to have satisfactory mechanical properties. While for the polypropylene blend, experimentation with another active compound, led to improvement of the mechanical properties of the blend. Antimicrobial tests were also conducted for the evaluation of the antimicrobial activity of immobilised antimicrobial agents against various microorganisms under dynamic contact conditions. The polymeric blends displayed high antimicrobial activity, while certain polymeric blend composition showed increased potential for use for antifouling purposes. The resulting innovations can be exploited for the manufacture of specialised products in the pharmaceutical, medical and food sector. Special plastic components also exhibit excellent antifouling properties and can be further employed for the production of fishnets. Due to waterborne activity growth of fouling organisms causes increased economic problems, related to the use of antifouling liquids or mechanical cleaning. Alternatively, the use of polymers with antifouling properties is expected to optimise the cost-effectiveness and efficiency of the fish-farming industry.
