Development And Safety Evaluation Of Polyethylene Film With Moisture Permeability

The PE film with moisture permeability and good security of food biology was developed in this study and CaCO₃ was added as an additive agents.New material and new composition was developed,2 patents was formed.We evaluate the the security of food biology from 2 ways.The results indicated that,The experimentation of new material.The surface modification of CaCO₃ was made by using titanate coupling agent.The activation grade,sedimentation volume and the viscosity of calcium carbonate before and after the modification were determined,and IR was used to characterize the modified calcium carbonate.The results indicated that the disperse ability of the modified calcium carbonate in organic medium was improved.The activation grade of the modified calcium carbonate reached 95%,when the dosage of titanate coupling agent TC-2 was 2%.The modification of calcium carbonate improved the function of calcium carbonate as filler.Add the modified CaCO₃ to LDPE,the film with moisture permeability was made. Various properties of the film were examined,such as tensile strength,O₂ permeability and moisture permeability.The results indicated that add calcium carbonate can bring countless small deficiency to make film with good moisture permeability.Consider from mechanical performance and moisture permeability of the film,when the amount of CaCO₃ was made by using titanate coupling agent is 20,the film is the best film.The film was used to package lettuce for examining fresh-keeping affections.The percentage of losting-weight,vitamin C,nitrate,SSC were examined,the content of CO₂ and O₂ in the plastic bag were tested,and the appearance change of lettuce was observed everyday,which were used to investigate the affections of the film to lettuce.According to the data we could know the film can make the storage time longer than before,it is good for the nutrition and eating quality of lettuce.Finally,according to the microorganism cultivation of the lotion of PE fresh-keeping film to colon bacillus,the analysis of the security of microorganism was made.