| The security of irradiated food had recently gained increasing attention with the repid development of technology of irradiation-application. However, radiation may change the packing material physical and chemical properties, and then affect the quality of the food.In this study, 7 kinds of polyvinylidene chloride(PVDC) were selected as objective materials due to its excellent performance and wildly application. After irradiated by dirrerent doses of 60Co-γ and high-energy electrons, the physical and chemical properties of PVDC and transport of harmful organic compounds in PVDC were investigated. The main content and result showed as follow:(1) An analyzing method of GC-MS which can test 26 plasticizers and 3 antioxidants in plastic packing materials was optimized and with texted 29 objects in 7 kinds of packaging materials which were irradiated by 0~100 kGy doses of 60Co-γ and high energy electron beam, results showed that two kinds of irradiation technology is evident in the DOP content change after irradiation, DHP were studied the optimμm processing, DEHP, DIBP, butylated hydroxytoluene and their characteristic radiolysis products 1, 3- DTBB, 2, 4- DTBP and 2, 6-2 tertiary butyl benzene quinone,results showed that two kinds of irradiation technology is evident in the DOP,DHP,DEHP,DIBP,BHTand their characteristic radiolysis products 1, 3-DTBB, 2, 4- DTBP and 2,6-di(tert-butyl)benzo-1,4-quinone.Two types of irradiation of plasticizer DEP, DEHP, DIBP affect similar trend,but after high energy electron beam irradiation DOP showed a trend of increase after down first,but after 60Co-γ irradiation is slowly reduced. After high energy electron beam irradiation plasticizer antioxidant content in materials within 15 kGy irradiation dose levels have declined obviously, but after 60Co-γ irradiation within 20 kGy irradiation dose markedly reduced. Two types of irradiation after irradiation hydrocarbons, alcohols, esters compounds content in the material are changing.(2) The optimization of gas chromatography- mass spectrometry(GC- MS) analysis method of 0 ~ 100 kGy 60Co-γ irradiation dose of 5 kinds of PVDCs material for long-term stability test, determination of content of 29 kinds of target in the packaging materials and migration,the results showed that althoμgh after a long time,various additives by irradiation dose not increase in great changes of the content change trend, the result is relatively similar, the influence of irradiation on the material is a long-term and stable, will not completely disappear over time. But after a long period.This different dose of irradiated material of plasticizer DOP,DHP,DEHP,DIBP of extraction as well as the migration to the migration of n-hexane were significantly improved. At the same time, the increasing of irradiation dose prevented the degradation of the material.(3) With reference to the national standard,determination of 0 ~ 100 kGy 60Co-γ irradiation and after high energy electron beam irradiation of 7 kinds of PVDCs material tensile strength and elongation, oxygen permeability and moisture permeability, chromaticity values. The results showed that after high energy electron beam irradiation materials increase tensile strength and elongation value is higher than gamma irradiation, changes in the tensile strength and elongation change obviously. Two types of irradiation irradiated material water vapor and oxygen throμgh the amount throμgh both present overall downward trend in low dose range, and within the scope of the high dose showed a trend of rising sharply.The 60Co-γ irradiation and chromaticity value changes after high energy electron beam irradiation were similar in 0 ~ 20 kGy irradiation dose range, in the 20 ~ 100 kGy range change material chroma value of the canon of high-energy electron beam irradiation △E than after 60Co-γirradiation.(4) With reference to the national standard,5 kinds of PVDCs material tensile strength and elongation, oxygen permeability and moisture permeability, chromaticity values are measured at 0 ~ 100 kGy 60Co-γ irradiation, the results showed that PVDC material tensile strength presented significant decline, present a tendency of increasing while the elongation after a long time. Oxygen permeability and the amount of water vapor are declining. Materials increase with the growth of the whole place time color change. The irradiation with a strong color change regularity of polymer materials.(5) The optimization of gas chromatography- mass spectrometry(GC- MS) analysis method of 0 ~ 100 kGy 60Co-γirradiation dose of PE, PP, PA, BOPA materials for long term stability test, the results showed that all packaging materials dichloromethane extract and n-hexane migration of plasticizer and antioxidant content increased. Tensile performance degradation, elongation, oxygen transmittance and water vapor transmittance. |
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