OLIANI, WASHINGTON L.PARRA, DUCLERC F.LIMA, LUIS F.C.P.LUGAO, ADEMAR B.2014-11-172014-11-182015-04-022014-11-172014-11-182015-04-02OLIANI, WASHINGTON L.; PARRA, DUCLERC F.; LIMA, LUIS F.C.P.; LUGAO, ADEMAR B. Protooxidation behaviour of HMS-PP. In: INTERNATIONAL NUCLEAR ATLANTIC CONFERENCE; MEETING ON NUCLEAR APPLICATIONS, 9th; MEETING ON REACTOR PHYSICS AND THERMAL HYDRAULICS, 16th; MEETING ON NUCLEAR INDUSTRY, 1st, September 27 - October 2, 2009, Rio de Janeiro, RJ. <b>Proceedings...</b> DisponÃvel em: http://repositorio.ipen.br/handle/123456789/11954.http://repositorio.ipen.br/handle/123456789/11954The radiation process has played an important role to produce polymers with controlled rheological properties. The main scope of the study is to evaluate the stability of High melt strength polypropylene (HMS-PP) prepared by gamma irradiation of PP (spheres) under acetylene atmosphere followed by a heating step to terminate reactions, in different doses of 12.5 kGy and 20 kGy. The samples submitted to the natural ageing for a period of one year were characterized by: thermogravimetry (TG), differential scanning calorimetry (DSC), infrared spectroscopy (FTIR) and scanning electron microscopy (SEM). The fundamental process that is believed to be the most significant in the mechanism of photooxidative degradation is the formation of hydroperoxides. The high energy UV light is capable of initiating bond scission within the polymer backbone, which leads to further chemical modification of the bonds via scissions and chain reactions through formation of radical species. The results showed that in pristine and HMS-PP samples exposed to UV radiation, oxidation reactions occur, resulting in chain scissions. The reactions occur preferentially in the amorphous phase owing to the higher permeability of oxygen.openAccessagingcalorimetrycobalt 60crackscross-linkingexperimental datagamma radiationheatinginfrared spectrameltingpolypropyleneradiation dosesradiation effectsscanning electron microscopystabilitytemperature dependencetensile propertiesthermal gravimetric analysistime dependenceultraviolet radiationProtooxidation behaviour of HMS-PPTexto completo de eventohttps://orcid.org/0000-0002-1737-3191https://orcid.org/0000-0002-7626-880X