| Polyvinyl Alcohol(PVA)can be produced on a large scale by non petroleum route.It is a non-toxic,degradable and low-cost green macromolecular material,and PVA film has the characteristics of oxygen resistance,water solubility,oil resistance,transparency and biodegradability.However,pure PVA film does not have antibacterial function,which limits its application in food packaging,biomedicine and other fields to a certain extent.In order to solve this problem,antibacterial degradable PVA film was prepared by blending Basic Magnesium Hypochlorite(BMH)with PVA.Among them,inorganic antibacterial agent BMH is a kind of white powder which is non-toxic,non irritating,low price,difficult to dissolve in water,non hygroscopic,has good chemical stability,and does not decompose when heated in air or even in neutral and alkaline solutions.It decomposes into reactive oxygen species in the presence of inorganic acids and has excellent antibacterial ability.It is an ideal filling material for the preparation of antibacterial materials.However,inorganic filler BMH is difficult to be compatible with polymer PVA,and is prone to agglomeration and poor interfacial compatibility during mixing.It will decompose rapidly in acidic PVA-1788(p H=5.5±0.2),resulting in ineffective antibacterial effect and poor single antibacterial effect.Therefore,two methods were used in the preparation of polyvinyl alcohol(PVA)antibacterial composites:The first method is to modify the surface of BMH with silane coupling agent KH-550,adjust the p H of acidic PVA-1788 to alkaline(an alkaline environment suitable for the growth of Escherichia coli and Staphylococcus aureus),and then compound it with polyvinyl alcohol(PVA)to prepare modified Basic Magnesium Hypochlorite/Polyvinyl Alcohol antibacterial composite membrane(modified BMH/PVA antibacterial composite membrane).The effectiveness of organic modification of BMH was proved by scanning electron microscope(SEM),contact angle analysis,bacteriostatic circle experiment and infrared technology(FTIR).The antibacterial property of modified BMH in PVA can be maintained by adjusting p H value(the antibacterial rate is close to 100%).When the content of organic modified BMH was 3%,the elongation at break of modified BMH/PVA antibacterial composite film increased by 25%,which not only made PVA film have antibacterial properties,but also improved its toughness.The second method is to use zeolite imidazole ester skeleton material(ZIF-8)as the carrier to load and disperse BMH and increase the contact area between antibacterial agent BMH and bacteria.Firstly,the optimum concentration ratio of BMH: ZIF-8 is 1:1 by plate counting method.Through SEM,X-ray powder diffraction analyzer(XRD)and nitrogen adsorption desorption test analyzer and other important characterization methods,the reasons for the synergistic antibacterial effect of BMH and ZIF-8 were explored.Finally,the Basic Magnesium Hypochlorite/zeolite imidazole ester skeleton material composite polyvinyl alcohol antibacterial membrane(BMH/ZIF-8 composite PVA antibacterial membrane)was prepared.The results showed that the addition of BMH/ZIF-8 composite antibacterial material decreased the light transmittance and oxygen resistance of PVA antibacterial film,the tensile strength first increased and then decreased,and the breaking elongation first decreased and then increased;In addition,the antibacterial properties and thermal stability of BMH/ZIF-8 composite PVA antibacterial film increased with the increase of the amount of BMH/ZIF-8 material. |
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