ELISABETH CARVALHO L. CARDOSO
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Artigo IPEN-doc 29931 Study of mechanical properties of inner tubes exposed to gamma radiation2023 - SCAGLIUSI, SANDRA R.; CARDOSO, ELISABETH C.L.; ESPER, FABIO J.; LUGAO, ADEMAR B.; WIEBECK, HELIODue to the technical evolution of tires, currently most automotive tires do not have an inner tube. However, truck, motorcycle and bicycle tires still use tires with inner tubes, mostly made of synthetic elastomeric material, which guarantees good potential for air restriction or longer periods for tire pressure failure. This work aims to study changes in the mechanical properties of a truck inner tire, after its exposure to gamma rays, to promote the subsequent recycling of the material. The choice of ionizing radiation is due to its ability to modify the structure and properties of materials, in addition to its applicability in recycling/recovering rubber. For the characterization of the samples, doses of 5, 10, 15, 20, 25 and 30 kGy were applied, and after irradiation as a sample, they were tested using the following characterization methods: traction and elongation at break, hardness, thermal aging and elemental analysis. Observed that is a decrease in the values of the mechanical properties of the samples after irradiation, mainly at doses greater than 10 kGy.Artigo IPEN-doc 29892 PLA, PBAT, Cellulose Nanocrystals (CNCs), and their blends2023 - COSTA, FERNANDA A.T. da; PARRA, DUCLERC F.; CARDOSO, ELISABETH C.L.; GUVEN, OLGUNPLA/PBAT (Poly (lactic acid)/Poly (butylene adipate-co-terephthalate)) blend is a biodegradable material commonly considered a potential alternative to polymeric products from petroleum sources. PLA is intrinsically brittle, endowed with a low elongation at break and poor impact strength that restricts its use for some applications while PBAT has high ductility, heat resistance, and impact resistance. However, PLA associated with PBAT results in an incompatible blend, due to poor interfacial adhesion. The compatibilization of PLA/PBAT can be improved through physical and chemical interaction between the components, and with exposure to ionizing radiation. Cellulose is the most abundant biodegradable polymer available and is considered the potential material to be used as reinforcement in sustainable composite materials, as well as nanocellulose while an alternative to synthetic nanoparticles. This review describes the state of the art of polymer blends of PBAT and PLA, in terms of manufacturability, compatibilization, biodegradation, radiation processing, and cellulose nanocrystal reinforcement.Artigo IPEN-doc 27810 Introduction to the study of mechanical properties of terpolymer PP/EPDM mixtures2021 - SCAGLIUSI, SANDRA R.; CARVALHO, ELIZABETH C.L.; LUGAO, ADEMAR B.Thermoplastic elastomers (TPEs), based in PP (Polypropylene) / EPDM (Ethylene Propylene Diene Monomer) have as purpose improving PP resistance and impact, aiming to a more comprehensive use in automotive market, among edifications, construction and packaging sectors, due to their recyclability properties. PP is a commodity, with a high melting point, high mechanical resistance and low density, posing a balance between physical and mechanical properties; in addition, it shows an easy processing, at low cost. In order to minimize this deficiency, EPDM, an impact modifier, can be used. Nevertheless, most of polymeric blends are incompatible and immiscible, i.e., show a mutual and limited solubility and in most of cases, a high interfacial tension. However, there is a relatively low interfacial tension (force which acts on transformation of a continuous structure in a dispersion) between PP and EPDM (approximately 0.3 mN.m-1), reducing the rate of breakup and facilitating the build-up of a continuous structure. This work aims to the study of compatibility of PP and EPDM blends and variation of mechanical properties, emphasizing that many properties of thermoplastic elastomers can be processed according with conventional thermoplastics methods: herein, PP/EPDM blends, 90/10, 80/20, 70/30 and 50/50 were characterized according to: Mechanical essays, Differential Scanning Calorimetry, Thermogravimetric Analyses, Melt Flow Index, Izod Impact Strength and Dynamic mechanical Analyses.Artigo IPEN-doc 27809 Effect of ionizing radiation applied to PLA used as compatibilizing agent in reinforced eGG shell PBAT/PLA bio-based composites2021 - CARDOSO, ELIZABETH C.L.; PARRA, DUCLERC F.; SCAGLIUSI, SANDRA R.; KOMATSU, L.G.H.; LUGAO, ADEMAR B.Bio-filler from eggshells as reinforcement of bio-based polymers are based on their benefits as adequate strength and stiffness, besides friendly, degradable and renewable environment. Eggshell is an agricultural waste considered as garbage, contributing to pollution; nevertheless, it can be transformed into bio-calcium carbonate, acquiring new values. As biodegradable polymers, there were chosen PLA (poly-lactic-acid) and PBAT (butylene adipate co-terephthalate), thermoplastics capable to be processed via conventional methods. PLA is a linear, aliphatic thermoplastic polyester, high in strength and modulus, but brittle. PBAT is a synthetic polymer, very flexible, based on fossil resources with high elongation at break, but low strength. It will be required the use of compatibilizers, for reducing interfacial tension exhibited by PLA/PBAT immiscible blend, considering their extreme glass transition temperatures: 62 ° C for PLA and – 30 ° C for PBAT. Herein it was used ionizing radiation for inducing compatibilization by free radicals, improving dispersion and adhesion of blend phases, without using chemical additives, at room temperature. PLA, acting as compatibilizer, was previously e-beam and gamma radiated, at 150 kGy. PBAT/PLA 50/50 blend with 15 phr of biofiller from avian eggs 125 μm particle size and both compatibilizers were homogeneized in a co-rotating twin-screw extruder, within a temperature profile 120 to 145 ° C, from hopper to die. Characterization involved: Differential Scanning Calorimeter, Thermogravimetric Analyses, Fourier Transform Infrared Spectroscopy, Wide Angle X-Ray Diffraction, Tensile Strength and Elongation at Break.