ELISABETH CARVALHO L. CARDOSO

ELISABETH CARVALHO L. CARDOSO

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Study of mechanical properties of inner tubes exposed to gamma radiation
2023 - SCAGLIUSI, SANDRA R.; CARDOSO, ELISABETH C.L.; ESPER, FABIO J.; LUGAO, ADEMAR B.; WIEBECK, HELIO
Due 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.
PLA, PBAT, Cellulose Nanocrystals (CNCs), and their blends
2023 - COSTA, FERNANDA A.T. da; PARRA, DUCLERC F.; CARDOSO, ELISABETH C.L.; GUVEN, OLGUN
PLA/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.
Introduction to foamability study of a LDPE subjected to gamma radiation
2022 - CARDOSO, ELIZABETH C.L.; SCAGLIUSI, SANDRA R.; PARRA, DUCLERC F.; LUGAO, ADEMAR B.
Nowadays, polymer foams have a wide application area due to their light weight, emphasizing resistance to impact, high thermal insulation and damping properties, among others. So, automotive, packing industry, electronic, aerospace, building construction, bedding and even medical applications are some of the fields where polymer foams are applied. Foams can be classified as open and closed: Closed-cell foam is provided with tiny and discrete pockets of gas, each one totally enclosed within polymer walls; open cell foam has tiny cells which are not completely closed. In this work, LDPE (low density polyethylene) resin foamability was investigated after exposure to ionizing radiation (gamma), at 5, 10 and 15 kGy. Characterizations included: melt flow index, melt strength and scanning electron microscopy.
Introduction to foamability study of a LDPE subjected to gamma radiation
2021 - CARDOSO, ELIZABETH C.L.; SCAGLIUSI, SANDRA R.; PARRA, DUCLERC F.; LUGAO, ADEMAR B.
Nowadays, polymer foams have a wide application area due to their light weight, emphasizing resistance to impact, high thermal insulation and damping properties, among others. So, automotive, packing industry, electronic, aerospace, building construction, bedding and even medical applications are some of the fields where polymer foams are been applied. Foams can be classified as open and closed: Closed-cell foam is provided with tiny and discrete pockets of gas, each one totally enclosed within polymer walls; open cell foam has tiny cells which are not completely closed. In this work, LDPE (Low Density Polyethylene) resin foamability was investigated after exposure to ionizing radiation (gamma), at 5, 10 and 15 kGy. Characterizations included: Melt Flow Index, Melt Strength and Scanning Electron Microscopy.
Study of mechanical and chemical properties stability of inner tubes exposed to gamma radiation
2021 - SCAGLIUSI, SANDRA R.; CARDOSO, ELIZABETH L.C.; ESPER, FABIO J.; LUGAO, ADEMAR B.; WIEBECK, HELIO
Nowadays, car tires are not provided with inner air or tubeless, pointing toward a technical evolution. Nevertheless, trucks tires even use at present inner tires, composed almost fully by a synthetic material, which ensures either a good potential for air constraint or longer periods for inspection of tires pressure. Inner tire is located inside the tire, which does not have any extra sealing in the wheel to withstand compressed air. It is designed to resist to expansion of these elements, inside common tires. This rubbery and vulcanized coating has chemical and physical characteristics which enable it to bear a very high air pressurization, avoiding leakages while protects tire outer frame. Inner tires models are exposed to higher temperatures and pressures that contribute to accelerate abrasion. This work aims to the study of mechanical properties changes of an inner tire used in trucks, after gamma rays exposure, in order to promote further material recycling. Ionizing radiation choice was due to its capacity to modify materials structure and properties besides its applicability for rubbers recycling/recovery. For samples characterization, non-irradiated and irradiated at 5, 10, 15, 20, 25 and 30 kGy, there were accomplished following tests: tensile and elongation at break, hardness, and thermal ageing and CHN elementary analysis. It was observed a decrease in mechanical properties for irradiated samples at doses higher than 20 kGy.
Influence of particle size of bio-calcium carbonate used as reinforcement of PBAT/PLA bio-based foams compatibilized with ionizing radiation
2019 - CARDOSO, ELISABETH C.L.; PARRA, DUCLERC F.; SCAGLIUSI, SANDRA R.; LUGAO, ADEMAR B.
Bio-filler from eggshells as reinforcement of bio-based polymers are based on their principle benefits such as good strength and stiffness besides being an environmental friendly, degradable and renewable material. Eggshell is an agricultural waste largely considered as garbage and discarded mostly because it contributes to pollution. Biodegradable polymers as PLA (poli-lactic acid) and PBAT (butylene adipate co-terephthalate) are thermoplastics which can be processed using most conventional polymer processing methods. PLA is high in strength and modulus (63 MPa and 3.4 GPa, respectively) but brittle (strain at break 3.8%) while PBAT is flexible and tough (strain at break ~710%). In order to reduce interfacial tension exhibited by PLA/PBAT blend, compatibilization is fundamental: herein it was used as compatibilizing agent PLA previously e-beam irradiated at 150 kGy: ionizing radiation induces compatibilization by free radicals, improving the dispersion and adhesion of blend phases, without the use of chemical additives and at room temperature. PLA/PBAT, 65/35 blend with bio-filler, from avian eggs, of 38 and 75 µm particle size were prior homogenized in a co-rotating twin-screw extruder and further foamed in a mono-screw extruder, by using CO2 as Physical Blowing Agent (PBA). Characterizations involved: Melt Index, DSC, TGA, FTIR, SEM, XRD and mechanical essays.
Nanocomposites foams of polypropilene modified by ionizing radiation containing CaCo3/ag° nanoparticles of bio-calcium carbonate-study of bactericidal effect
2019 - PARRA, DUCLERC F.; SILVA, ORELIO L. da; KOMATSU, LUIZ G.; CARDOSO, ELIZABETH C.L.; LUGAO, ADEMAR B.
This paper presents a study of high melting strengh polypropylene (HMSPP) foams by gamma irradiation with insertion of silver nanoparticles (AgNPs) adsorbed in carrier of CaCO3 (natural source) aiming bactericidal effect. The use of silver (Ag°) gives important antibacterial property since silver is highly toxic against bacterae. The HMSPP matrix was processed in a twin screw extruder under CO2 atmosphere and polypropylene nanocomposites (HMSPP-AgNC) were obtained in different concentrations of silver. The material was characterized by scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), field emission scanning electron microscopy (FESEM), X-ray diffraction spectroscopy (XRD), cytotoxicity assay and reduction colony-forming-unit (CFU). The analyzed foams showed spherical clusters and homogeneous regions with good distribution of the silver nanoparticles. Furthermore, the HMSPP@AgNCs foams exhibited a antibacterial efficiency against E. coli and S. aureus due to the presence of the biocidal silver nanoparticles.
Introduction to the study of mechanical properties of terpolymer PP/EPDM mixtures
2021 - 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.
Effect of ionizing radiation applied to PLA used as compatibilizing agent in reinforced eGG shell PBAT/PLA bio-based composites
2021 - 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.
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.