| Plastic has been widely used in food packaging because of its excellent properties.To improve the quality and performance of plastic,often added a variety of small molecules chemical additives in the production and processing.These small molecules may migrate into the food that lead to the food pollution and endanger the health of consumers when the plastic packaging materials and food in direct contact.So the study of food packaging material migration is an important aspect of maintaining food safety.The study of the migration regular can provide a theoretical basis for the prediction of the migration of plastic production and processing,so as to curb the food safety problems caused by the migration at the source.This paper mainly analyzes the migration of BHA?BHT?Irganox1076?Irganox1010?Irgafos168 of PP plastic masterbatch with different particle size.With different temperatures,the migration quantities of antioxidants films into anhydrous ethanol,ethanol 75%,ethanol 50%,ethanol 25% ethanol were measured using HPLC.Based on the Scatchard-Hildebrand thermodynamics theory,a mathematical model predicting the equilibrium partition coefficient of migrants was established.Then the partition coefficients of experiment data were calculated compared with the modeling values.The influence of factors such as temperature,migratory species,particle size of polymer and the type of simulants on the difference was discussed.Through further theoretical analysis in order to measure the applicability of the theoretical model.The main research results are as follows:(1)According to the experimental data,the relationship between the concentration of the migrants in the simulants and the migration time was made using Origin 9.0.It is found that the migration curves conform to the equation Y = a(1-exp-bx),where the coefficients a and b have a certain relationship with temperature,polymer particle size and alcohol concentration.(2)The migrants concentration in the simulation increases with the decrease of the particle size and the partition coefficient is gradually reduced.And the partition coefficient(K)and the specific surface area(S)of the plastic correspond to the equation: lnK = A + B/S + C/S ^ 2.(3)Different temperature has a greater influence on the migration and migration speed.With the increase of temperature,the shorter time of migration equilibrium,the greater the migration equilibrium,the faster the migration speed,the smaller the partition coefficient,the greater the diffusion coefficient.The partition coefficient(K)and the temperature(T)correspond to the equation: lnK = a + b*1/T.Based on this,the enthalpy change ?Hm of the migration reaction can be obtained.Diffusion coefficient and temperature have a good linear relationship: lnD = A + B/T,but with the size of the polymer particle is not directly related.(4)The composition of the simulants also has a greater effect on migration.At lower alcohol concentrations,the Irganox1076,Irganox1010,Irgafos168 was lowe r than the detection limit,which may be related to its molecular weight and solubility.BHA,BHT maximum migration and migration rate increased with the concentration of alcohol,under the same conditions to achieve the balance of migration time is also s ignificantly longer with anhydrous ethanol simulation.(5)The calculated experimental results of the partition coefficient are compared with the theoretical values of the mode l.It is found that the difference between temperature,migrants and simulations is different.For BHA and BHT,the higher the temperature,the closer the theoretical partition coefficient(Fsim)is to the experiment partition coefficient(Fexp),the antioxidant 1076 and 168 have no obvious regular;The greater the specific surface area of plastic,and the concentration of simulated liquid alcohol,the closer the two.It can be explained that the theoretical model under different conditions,the accuracy of the forecast is different,it need to be further amended. |
PDF Full Text Request