Research On Preparation And Performances Of Antibacterial Polypropylene Packaging Materials

Antibacterial materialscan inhibit the growth and reproduction of bacteriaeffectively, which is important toprotect human beings’health when applied in our daily life.This paper taking palygorskite as antibacterial carrier, taking zinc ion as antibacterial metal ion, synthetizes palygorskite loaded zinc by an ion exchange method to analysis the synthetic condition, property and crystalline structure of antibacterial agent. Add the composite antibacterial agent to PP resin by masterbatches. First prepare the antibacterial masterbatches, then mix the masterbatches and PP particles at different percentages to blow the antibacterial PP film. Discuss the dispersive influence of PP film by the method of masterbatches and analysis the antimicrobial activity, crystallization property, mechanical property, barrier property, optical property and heat-sealing property of antibacterial PP film.The optimum conditions for the preparation of zinc-exchanged palygorskite are:the concentration of ZnSO4 solution is 0.7mol/L, the reaction temperature is 80℃ and the reaction time is 4h. At this condition the zinc quantity in the composed antibacterial agent is the most,5.052mg/ml. The concentration of ZnSO4 solution has the most influential to the composition of antibacterial agent. The metal ion in the antibacterial agent expresses the antimicrobial activity. So the more zinc quantity, the better inhibitory effect. The inhibition tests of antibacterial agent demonstrate that zinc-exchanged palygorskite has the obvious inhibitory effect against E.coli and S.aureus. The diameter of inhibition zone against E.coli and S.aureus is 27.5mm and 25mm. FT-IR shows that the palygorskite and the zinc-exchanged palygorskite have the same infrared absorption characteristic peak. Though the part of zinc ions react with OH bond and a few crystallography parameters have changed, the zinc-exchanged palygorskite still exists the basic crystal form of the palygorskite.When the content of antibacterial agent is 5%, the antibacterial PP film has the good inhibitory effect, mechanical property, barrier property and optical proterty. The antibacterial PP film also possesses good antibacterial durability, the antibacterial rate of E.coli and S.aureus is 93.9% and 93.1%. Compared with adding the agent to PP resin directly, the method of masterbatches can help the antibacterial agent well distributed to improve the inhibitory effect of the film. By the DSC analysis, the zinc-exchanged palygorskite expresses the effect of heterogeneous nucleation when the PP film crystallized. The result is that the number of crystal nucleus has increased, the crystallization speed and crystalline have enhanced. But the effect on the melting temperature of PP film is small. The best conditions of heat-sealing are:the temperature is 175℃, the time is 0.5s, the pressure is 170kpa. The temperature is the most influencing. At that conditions the heat-sealing strength is biggest,24.8N.