@article { ISI:000239536200026,
	title = {Stabilization of gamma-sterilized biomedical polyolefins by synergistic mixtures of oligomeric stabilizers},
	journal = {Polymer Degradation and Stability},
	volume = {91},
	number = {10},
	year = {2006},
	month = {OCT},
	pages = {2451-2464},
	publisher = {ELSEVIER SCI LTD},
	type = {Article},
	address = {THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, OXON, ENGLAND},
	abstract = {<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>},
	keywords = {Antioxidants, discoloration, ethylene-propylene copolymer, gamma-sterilization, stabilization, tensile properties},
	issn = {0141-3910},
	doi = {10.1016/j.polymdegradstab.2006.03.010},
	author = {Alariqi, Sameh A. S. and Kumar, A. Pratheep and Rao, B. S. M. and Tevtia, Amit K. and Singh, R. P.}
}
@article {34},
	title = {Stabilization of gamma-sterilized biomedical polyolefins by synergistic mixtures of oligomeric stabilizers. part II. polypropylene matrix},
	journal = {Polymer Degradation and Stability},
	volume = {92},
	number = {2},
	year = {2007},
	month = {FEB},
	pages = {299-309},
	publisher = {ELSEVIER SCIENCE BV},
	type = {Article},
	address = {PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS},
	keywords = {Ceramics, Chemical synthesis, Electron microscopy, Oxides, X-ray diffraction},
	issn = {0167-577X},
	author = {Alariqi, Sameh A. S. and Kumar, A. Pratheep and Rao, B. S. M. and Singh, R. P.}
}
@article {43917,
	title = {Stabilization of γ-sterilized low-density polyethylene by synergistic mixtures of food-contact approval stabilizers},
	journal = {International Journal of Industrial Chemistry},
	volume = {8},
	year = {2017},
	month = {JUN},
	pages = {145{\textendash}156},
	abstract = {In our previous studies, we have found the synergistic combinations of stabilizers which follow different mechanisms of stabilization and are approved for food contact applications. The present attempt is to test the potentials of those systems in stabilizing γ-sterilized low-density polyethylene (LDPE). The results were discussed by comparing the stabilizing efficiency of mixtures with and without phenol systems as well as with their counterparts of isotactic polypropylene (iPP) and ethylene-propylene copolymers (EP) matrices. LDPE has been melt-mixed with tertiary hindered amine stabilizer (tert-HAS), oligomeric HAS stabilizer, phenolic and organo-phosphite antioxidants and subjected to γ-sterilization. Stabilization in terms of changes in oxidation products, tensile properties, yellowing and surface morphology was evaluated by FT-IR spectroscopy, Instron, colorimetry, and scanning electron microscopy (SEM), respectively. The results of the present study confirm the validity of those systems for protecting various polyolefins against γ-sterilization. The results showed that the synergism, antagonism and the trend in stabilization efficiency of the binary, ternary and quaternary stabilizer systems were almost similar in LDPE, iPP and EP matrices. The binary system of oligomeric HAS and tert-HAS has shown the antagonistic effect of stabilization, whereas their combination with organo-phosphite has exhibited synergistic effect even at higher doses of γ-sterilization. The combination of oligomeric HAS, tert-HAS, organo-phosphite and hindered phenol exhibited improved stabilization efficiency than single or binary additive systems. The phenol systems have shown long term of stability than that of phenol-free systems. It was found that the consumption of oligomeric stabilizer significantly depends on the components of stabilization mixture. It was concluded that the stability of polyolefins (LDPE, iPP and EP) against γ-sterilization can be achieved by blends of different stabilizers which are approved for food contact applications.},
	doi = {10.1007/s40090-017-0117-0},
	author = {Alariqi, Sameh A. S. and Al-Areqi, Niyazi A. S. and Alaghbari, Elyas Sadeq and Singh, Raj Pal}
}
