02479nas a2200265   4500008004100000022001400041245011100055210006900166260009900235300001400334490000700348520149400355653001701849653001801866653003301884653002401917653001801941653002301959100002601982700002002008700001902028700002102047700001802068856012702086       2006                        eng d  a0141-391000aStabilization of gamma-sterilized biomedical polyolefins by synergistic mixtures of oligomeric stabilizers0 aStabilization of gammasterilized biomedical polyolefins by syner  aTHE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, OXON, ENGLANDbELSEVIER SCI LTDcOCT  a2451-24640 v913 a<p>The stabilization of polyolefins against gamma-sterilization has been studied with single or binary additive system. The present attempt is to utilize synergistic mixtures of stabilizers which are approved for food contact applications. Ethylene-propylene (EP) copolymer has been melt-mixed with hindered amine stabilizers (HAS), phenolic antioxidants and organo-phosphites (hydroperoxide decomposer). Samples were sterilized with different doses of gamma-radiation. Stabilization was characterized in terms of changes in the functional groups (oxidation products), tensile properties, yellowing and surface morphology by FTIR spectroscopy, Instron, colorimetry (reflectance) and scanning electron microscopy (SEM), respectively. Results were discussed by comparing the stabilizing efficiency of mixtures with and without phenol system. Among phenol containing systems, where we mostly observe discoloration due to the oxidation of hindered phenol and the combination of secondary HAS, tertiary HAS, organo-phosphite and hindered phenol exhibited improved stabilization efficiency than single or binary additive systems. The mixture of secondary HAS and tertiary HAS, has shown antagonistic effect of stabilization whereas their combination with organo-phosphite has exhibited synergistic effect of stabilization even at higher doses of gamma-sterilization. The effects have been explained through the interaction between the stabilizers. (c) 2006 Elsevier Ltd. All rights reserved.</p>10aAntioxidants10adiscoloration10aethylene-propylene copolymer10agamma-sterilization10astabilization10atensile properties1 aAlariqi, Sameh, A. S.1 aKumar, Pratheep1 aRao, B., S. M.1 aTevtia, Amit, K.1 aSingh, R., P.  uhttps://library.ncl.res.in/content/stabilization-gamma-sterilized-biomedical-polyolefins-synergistic-mixtures-oligomeric-2