Preparation And Study Of Antimicrobial Biaxially Oriented Polyterafluoroethylene Film

A series biaxially stretching anti-microbial polyterafluoroethylene (PTFE) films were prepared from PTFE resin by the processes of blend, impaction, extrusion, compaction with different antimicrobial agents added. The differences of antimicrobial activity, mechanics properties and water vapor permeability of the films were compared. Further more, multi-microporous structures of the films were observed by Scanning electron microscopy (SEM).Using E. coli , S. aureus, B.s and St.e as experimental microbials, antimicrobial activities of different films with CAH-2,AM-5,nano-Ag,nano-TiO₂,chitosan added were compared through antimicrobiall cycle method and shake flask method. The results showed that CAH-2 and chitosan were soluble antimicrobial agents, and the antimicrobial ratios of films added with CAH-2 were all above 90% towards four kinds of experimental microorganism, which indicated that this kind of film had the best antimicrobial effect. The antimicrobial activities of the films added with AM-5,nano-Ag and chitosan were ordinary but better than film added with nano-TiO₂ which was the worst of all. After treated by dipping in weak acid and weak base for three months and washing 50 times, the antimicrobial effect of film added with CAH-2 was still above 90%, however the antimicrobial effect of films added with AM-5 and chitosan decreased significantly. The antimicrobial effect of film added with nano-Ag was decreased slowly and it still kept at high level. Therefore, the antimicrobial activity of film added with CAH-2 were highly effective, durable and broad-spectrum.The mechanics properties of antimicrobial biaxial stretching PTFE films were also studied. The results showed that the tensile-strength and elongation at break of PTFE films were both increase at first and then decreased. The optimized tensile-strength and elongation at break of PTFE films were obtained at the strain rate between 1.5 to 2. It was also found that mechanics properties of films added with solid antimicrobial agents such as AM-5,nano-Ag,nano-TiO2 and chitosan were enhanced, while those of films added with liquid antimicrobial such as CAH-2 was reduced. By adding CAH-2 and nano-Ag together, a kind of PTFE film with excellent mechanical properties and antimicrobial activity was obtainedThrough the studies of the moisture permeable performance of antimicrobial biaxial stretching PTFE films, it was found that the water vapor permeabilities of films added with different amounts of and kinds of antimicrobial agents were slightly decreased. But there was no obvious relation between the amount of antimicrobial agents added and the decrease of water vapor permeability. The water vapor permeability of films would run at a relatively narrow range along with the different amount of antimicrobial agents added.Finally, scanning electron microscopy (SEM) micrograpHs exhibited microstructures of antimicrobial biaxial stretching PTFE films. SEM picture showed that the PTFE fibers were stretched from the raw PTFE particles through biaxial stretching, and fibers constructed microporous structures with the knots. Antimicrobial agents and PTFE are uniformly mixed to conform the film with fibers-knots crossing structures which have the function of waterproof and moisture permeable.