| It is well known that the addition of inorganic nanoparticles will improve the properties of polymer material,and it has an excellent antibacterial property.However,copper nanoparticles will migrate into food from food packaging materials,which may be harmful to health.In this paper,the following problems were mainly studied:（1）Nanocopper and modified nanocopper by（3-Aminopropyl）triethoxysilane（KH550）were mixed with PP granules,new granules containing nanocopperand modified nanocopper were added into the composite films by a film-blowing machine.The composite films and copper nanoparticles were characterized by scanning electron microscope.There was no chemical bond formed in nanocopper with the coupling agent addition through using Fourier transform infrared spectroscopy.（2）3%acetic acid and ultrapure water were chosen as food simulants to explore the influence of food simulation,three kinds of structure（PPB,PPR and PPH）and oxygen on the migration of copper from nanocopper/PP composite films into food simulants.The films were exposured to 3%acetic acid at 20,40 and 70℃,The migration of copper to food simulants increases with time and temperature until equilibrium.Copper migration did not appear to be significant in the case of PPR and PPH compared with PPB with a maximum value at 20℃;copper migration did not appear to be significant in the case of PPB and PPR compared with PPH with a maximum value at 40℃;the migration of copper in PPH was greater than PPR,the migration of copper in the PPB is minimum at 70℃.GFAAS detected no copper in the ultra-pure water.The higher the oxygen content during storage,the more copper migration is promoted.（3）The research was designed to investigate the effects of Irgafos 168,KH550and different treatment conditions on the migration of copper from composite films to3%acetic acid,and the antioxidation and antibacterial properties of the films were also detected.For PPR and PPH composite films,the migration of copper from the films with Irgafos 168 is greater than that without Irgafos 168（P<0.05）,however,the migration of copper from PPB composite films is opposite.At 20℃,the maximum migration ratios of copper from PPH-Cu-168-KH550,PPR-Cu-168-KH550 and PPB-Cu-KH550 films into 3%acetic acid were 8.49%,5.44%and 3.13%respectively;at 40℃,the maximum migration ratios of copper from PPH-Cu-168-KH550,PPR-Cu-168-KH550 and PPB-Cu-KH550 films into 3%acetic acid were 22.5%,8.37%and 5.96%respectively;at 70℃,the maximum migration ratios of copper from PPH-Cu-168-KH550,PPR-Cu-168-KH550 and PPB-Cu-KH550 films into 3%acetic acid were 34.51%,20.3%and 10.82%respectively.The addition of the coupling agent KH550 had little effect on the migration rate of copper（P>0.05）.Sunshine and 30 min UV treatment had no significant effect on the migration of copper in PPH-Cu-KH550（P>0.05）,but inhibited copper migration in PPH-Cu-168-KH550;γ-irradiation increased the migration of copper in PPH-Cu-KH550 and PPH-Cu-168-KH550significantly.The composite films have certain antioxidant effect.The composite films have no obvious antibacterial effect on Staphylococcus aureus and Shigella.When the concentration of copper in the film increased to 1.25%,the addition of copper enhanced the inhibition of Staphylococcus aureus and Shigella.（4）The existing morphology of copper in migration solution and the migration of copper from the nanocopper/PP composite films to food were studied.The results showed that there were no copper nanoparticles in 3%acetic acid and copper nanoparticles were detected in 10%ethanol at 60°C for 10 days.The migration solution of 10%ethanol was characterized by SEM,and the elemental composition of the nanoparticles in the migration solution was analyzed by EDX.It was proved that the copper in the migration solution was a nano-morphology.The migration of copper in white vinegar was greater than 3%in acetic acid,apple vinegar and lemon juice（P<0.05）.The maximum migration was 0.65 mg kg-1. |
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