ELISABETH CARVALHO L. CARDOSO

ELISABETH CARVALHO L. CARDOSO

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Ionizing radiation compatibilization in bio-based blends from PBAT/PLA reinforced with bio-eggshell
2020 - CARDOSO, E.C.; PARRA, D.F.; SCAGLIUSI, S.R.; KOMATSU, L.G.; LUGAO, A.B.
Plastics global annual production exceeds 300 million tons and 99% is originated from oil or fossil combustibles. The amount of plastics wastes utilized exceeds the amount into landfills, prejudicing effectively the environment. As an alternative, they are being slowly replaced by bioplastics, as PLA (poly-lactic acid) and PBAT (butylene adipate co-terephthalate). Food and dairy industries produce annually huge amounts of avian eggshells residues and their disposition presents a serious environmental risk. Bio-load from avian eggshells as polymers reinforcement is based in their higher benefits as resistance and rigidity besides being a friendly environmental material, degradable and renewable. PLA and PBAT are thermoplastics capable to be processed by conventional methods: nevertheless, due to their high interfacial tension, it is required the use of compatibilizers. In this work, additives and heat generally used as compatibilizers were replaced by e-beam radiation, at 150 kGy dose. PBAT/PLA blends were prepared at the weight ratio of 82 / 18 and 5.0 phr of PLA 150 kGy e-beam radiated, at 2.5, 5.0 and 10.0 phr of bio-eggshells. Samples were homogeneized in a co-rotating twin-screw extruder and further characterized for: DSC, TGA, FTIR, XRD and Mechanical essays.
The degrading effects of the radiation on the properties of butyl rubber compounds
2020 - SCAGLIUSI, S.R.; CARDOSO, E.C.; LUGAO, A.B.
Polymeric materials (plastics and rubber) have been contributing in a continuously and raising way for the generation of litter and industrial wastes discarded in landfills. Gamma ionizing radiation has capacity for changing structure and properties of polymeric materials and can be applied to almost all types of polymers; irradiation is an expectation for problem-solving of rubber wastes management that can be utilized as raw-materials or chemical additives. butyl rubber has excellent mechanical properties and oxidation resistance, as well as low gas and water vapor permeability. At the initial stage of irradiation the degradation of butyl rubber occurs predominantly via random chain-scission This work aims to the introduction of a new recovery technique for butyl rubber, by using processing via gamma-rays followed by shear. 5 kGy, 15 kGy, 25 kGy, 50 kGy, 100 KGy, 150 kGy and 200 KGy doses were used, in order to study the feasibility of butyl rubber for recycling. Doses within 5 to 25 kGy applied to butyl rubber and pointed toward a less degraded material.
Effect of gamma radiation on crosslinking of butyl rubber compounds
2016 - SCAGLIUSI, SANDRA; LUGAO, ADEMAR B.; CARDOSO, ELIZABETH C.L.
Butyl rubbers when are subjected to high energy radiation the forms free radicals that initiate various chemical reactions. These reactions alter the molecular distribution of these rubbers by crosslinking or scission affecting their physical and mechanical properties. The aim of this work is the analysis of the effect induced by g-irradiation on the crosslinking density in butyl rubbers (pristine or modified by chlorination and bromination) by swelling measurements accomplished before and after irradiation at 0 kGy, 5 kGy, 25 kGy 50 kGy, 100 kGy and 200 kGy doses, allowing the evaluation of cross-linking density according with Flory-Rehner equation. Rheometric tests were also carried out to complete the characterization of radiation effects in this rubber structures. Both types of investigations describe the crosslinking degree relative to unprocessed materials. It can be noticed that the modification in material structure by the formation of new three-dimensional network changes the features of studied rubbers. This assessment was confirmed by swelling measurements on all g-exposed butyl rubbers at various doses. The estimation of crosslinking density by Flory-Rehner equation is a proper procedure for the qualification of radiation resistance. The level of cross linker (sulfur, resin or donor sulfur) in the butyl rubber formulation plays also important role in the degradation process. The predominance of chain scission can also be remarked in butyl rubber. The change in crosslinking density of butyl rubber compounds emphasizes that the mechanism of degradation is strongly influenced mainly by irradiation dose for doses above 50 kGy, since the process of chain scission predominates over the crosslinking reaction.
The effect of gamma-radiation on biodegradability of synthetic PHB structural foams PP/HMSPP based
2016 - CARDOSO, ELIZABETH C.L.; SCAGLIUSI, SANDRA R.; LUGAO, ADEMAR B.
Radiation resistance assessment of EPDM formulation for electrical insulation
2016 - SCAGLIUSI, SANDRA R.; CARDOSO, ELIZABETH C.L.; ZAHARESCU, TRAIAN; LUGAO, ADEMAR B.
Effects of bio-CaCO3 nanoparticles and graphene nanosheets on properties of PBAT/PLA flexible films treated by ionizing radiation
2016 - REIS, PEDRO R.S.; CARDOSO, ELIZABETH C.L.; LOURENÇO, FELIPE R.; ORTIZ, ANGEL V.; RANGARI, VIJAY K.; MOURA, ESPERIDIANA A.B.
Influence of antioxidant loading on the 'gamma'-exposure of ethylene-propylene terpolymer
2014 - ZEN, HELOISA A.; ZAHARESCU, TRAIAN; MARINESCU, MARIANA M.; SCAGLIUSI, SANDRA R.; CARDOSO, ELIZABETH C.L.; LUGAO, ADEMAR B.
Dynamic mechanical and rheological properties of polypropylene modified by gamma irradiation in the presence of polyfunctional monomers
2004 - LUGAO, A.B.; ARTEL, B.W.H.; PARRA, D.F.; CARDOSO, E.L.; LIMA, L.F.C.P.; OTAGURO, H.
Evaluation of 'Payne effect' in radiation-induced modification of chlorobutyl rubber
2010 - SCAGLIUSI, S.R.; PARRA, D.F.; CARDOSO, E.C.L.; LIMA, L.S.C.E.; LUGAO, A.B.
Gamma-irradiation cross-linked LDPE foams: characteristics and properties
2010 - CARDOSO, E.C.L.; SCAGLIUSI, S.R.; PARRA, D.F.; LUGAO, A.B.