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  • IPEN-DOC 26393

    FERREIRA, EDUARDO G.A. ; MARUMO, JULIO T. ; FRANCO, MARGARETH K.K.D. ; YOKAICHIYA, FABIANO; VICENTE, ROBERTO . 10000 years cement: Can hydrated cement last as much as long-lived radionuclides?. Cement and Concrete Composites, v. 103, p. 339-352, 2019. DOI: 10.1016/j.cemconcomp.2019.05.016

    Abstract: This review is focused on the long-term performance of cementitious materials in a repository for radioactive waste. During the last few years, the disposal of disused sealed radioactive sources (DSRS) in a borehole type repository has been studied by many countries. The borehole concept is particularly useful to dispose of spent nuclear fuel and DSRS. In boreholes for DSRS, cementitious materials are intended to be used as structural material, immobilization matrix and as backfill. The understanding of the performance of these materials is essential to ensure the safety of the facilities during their required lifetime, from centuries to many thousands of years, depending on the initial activity and half-life of the waste. This review approaches the behavior of the cement from the hydration and hardening to the long-term processes that can affect its durability. Three main causes of failure of repository-engineered barriers are recognized: a) the formation of a preferential pathway for the migration of the contained radionuclides to the biosphere; b) loss of resistance and cohesion of the structural cementitious material; and c) the increase in the corrosion processes of the metallic components of the structures that affect the overall containment of the facility.

    Palavras-Chave: cement industry; portland cement; radioactive wastes; geologic formations; underground disposal; performance; chemical composition; mineralogy; radiations; magnetic fields; hydration

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  • IPEN-DOC 25206

    FREITAS, LUCAS F. de ; VARCA, GUSTAVO H.C. ; BATISTA, JORGE G. dos S. ; LUGAO, ADEMAR B. . An overview of the synthesis of gold nanoparticles using radiation technologies. Nanomaterials, v. 8, n. 11, 2018. DOI: 10.3390/nano8110939

    Abstract: At a nano-level, optical properties of gold are unique and gave birth to an emerging platform of nanogold-based systems for diverse applications, because gold nanoparticle properties are tunable as a function of size and shape. Within the available techniques for the synthesis of gold nanoparticles, the radiolytic synthesis allows proper control of the nucleation process without the need for reducing agents, in a single step, combined or not with simultaneous sterilization. This review details and summarizes the use of radiation technologies for the synthesis and preparation of gold nanoparticles concerning fundamental aspects, mechanism, current pathways for synthesis and radiation sources, as well as briefly outlines final applications and some toxicity aspects related to nanogold-based systems.

    Palavras-Chave: gold; nanoparticles; gamma radiation; electron beams; x-ray sources; radiolysis; nanotechnology; medicine; diagnostic uses; ionizing radiations

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  • IPEN-DOC 27582

    LIMA, CAROLINE S.A. de ; BALOGH, TATIANA S. ; VARCA, JUSTINE P.R.O. ; VARCA, GUSTAVO H.C. ; LUGAO, ADEMAR B. ; CAMACHO-CRUZ, LUIS A.; BUCIO, EMILIO; KADLUBOWSKI, SLAWOMIR S.. An updated review of macro, micro, and nanostructured hydrogels for biomedical and pharmaceutical applications. Pharmaceutics, v. 12, n. 10, p. 1-28, 2020. DOI: 10.3390/pharmaceutics12100970

    Abstract: Hydrogels are materials with wide applications in several fields, including the biomedical and pharmaceutical industries. Their properties such as the capacity of absorbing great amounts of aqueous solutions without losing shape and mechanical properties, as well as loading drugs of different nature, including hydrophobic ones and biomolecules, give an idea of their versatility and promising demand. As they have been explored in a great number of studies for years, many routes of synthesis have been developed, especially for chemical/permanent hydrogels. In the same way, stimuli-responsive hydrogels, also known as intelligent materials, have been explored too, enhancing the regulation of properties such as targeting and drug release. By controlling the particle size, hydrogel on the micro- and nanoscale have been studied likewise and have increased, even more, the possibilities for applications of the so-called XXI century materials. In this paper, we aimed to produce an overview of the recent studies concerning methods of synthesis, biomedical, and pharmaceutical applications of macro-, micro, and nanogels.

    Palavras-Chave: hydrogels; drugs; synthesis; cross-linking; skin; animal tissues; gamma radiation

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  • IPEN-DOC 27621

    COSTA, ROBSON S. ; MOURA, ESPERIDIANA A.B. . A bibliometric analysis of the strategy and performance measurement of the polymer matrix nanomaterials development scenario globally, and the participation of Brazil. In: LI, JIAN (Ed.); ZHANG, MINGMING (Ed.); LI, BOWEN (Ed.); MONTEIRO, SERGIO N. (Ed.); IKHMAYIES, SHADIA (Ed.); KALAY, YUNUS E. (Ed.); HWANG, JIANN-YANG (Ed.); ESCOBEDO-DIAZ, JUAN P. (Ed.); CARPENTER, JOHN S. (Ed.); BROWN, ANDREW D. (Ed.). Characterization of Minerals, Metals, and Materials. Cham, CZ, Switzerland: Springer Nature Switzerland AG, 2020. p. 329-342, (The Minerals, Metals & Materials Series). DOI: 10.1007/978-3-030-36628-5_31

    Abstract: Extensive studies have been conducted worldwide on the strategy for the development of nanomaterials. One of the known strategies for this has aroused interest in the market is the incorporation of the nanoparticles, extracted from the residues in thematrices of the polymers for the production of environmentally correct nanocomposites. This work presents a survey of the scientific knowledge of nanomaterials of the polymer matrix and a panoramic view of the evolution of these nanomaterials are subject, in order to meet the criteria of sustainable development due to the environmental concerns. This study also intends to use bibliometric tools to database acquisition and analysis of bibliographic reviews for an evaluation of the scenarios in the world on the development of polymeric nanomaterials based on three different classes of polymeric nanocomposites: polymer/clay; polymer/graphene, and polymer/nanocellulose nanocomposites.

    Palavras-Chave: statistical data; nanomaterials; nanocomposites; scientific personnel; knowledge management; polymers

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  • IPEN-DOC 27852

    AQUINO, S. ; LIMA, J.E.A.; BORRELY, S.I. . Bioburden proliferation in vehicle air filters waste: the use of gamma radiation on fungal decontamination. Brazilian Journal of Radiation Sciences, v. 9, n. 1A, p. 1-14, 2021. DOI: 10.15392/bjrs.v9i1A.1254

    Abstract: This study aimed to analyze the fungal contamination of air-conditioning filters waste (n=20) as an indicator of Quality Air Indoor from different car models, that were collected from 10 exchange stations located in the South, North, West, Downtown and East, of the city of São Paulo in São Paulo State, Brazil, during the period from October 2017 to November 2018. Sampling of filter particles (33 fragments of 10 × 10-mm size) were plated onto solidified Potato Dextrose agar in Petri dishes. The samples were incubated for 7 days at 25 °C and were stored in a standard Biochemical Oxygen Demand incubator, for growth of fungal cultures. After incubation, the fungal culture in the plates was evaluated, and the total counting of infected fragments was expressed as a percentage. The fungi were examined by Lactophenol blue solution staining for microscopy. All samples were contaminated with various fungal genera, including Aspergillus, Alternaria, Cladosporium, and Penicillium. The study also aimed to evaluate the fungal enumeration in the samples that were irradiated with dose of 10 kGy to fungal decontamination of air-conditioning filters waste. Of total samples, 50% were completed decontaminated, but some genera such as Aspergillus, Penicillium, Rhizopus, Cladosporium and yeasts demonstrated radioresistance at the dose of 10 kGy. The only yeast called Rhodotorula showed an increase in growth after the irradiation process.

    Palavras-Chave: air conditioning; air filters; air quality; automobiles; cobalt 60; contamination; decontamination; fungi; wastes

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  • IPEN-DOC 29241

    ANGELOCCI, LUCAS V. . Caracterização dosimétrica de uma nova fonte oftálmica de Irídio-192 usando métodos experimentais e simulações de Monte Carlo / Dosimetric characterization of an ophthalmic Iridium-192 source using experimental methods and Monte Carlo simulation . 2022. Tese (Doutorado em Tecnologia Nuclear) - Instituto de Pesquisas Energéticas e Nucleares - IPEN-CNEN/SP, São Paulo. 180 p. Orientador: Maria Elisa Chuery Martins Rostelato. DOI: 10.11606/T.85.2022.tde-07112022-165046

    Abstract: Aplicadores contendo sementes com núcleos radioativos são utilizados na braquiterapia oftálmica, para tratamento de câncer ocular, em um processo cirúrgico onde são suturados ao globo ocular do paciente por certo período de tempo, planejado para entregar a dose determinada ao alvo. Um novo modelo de semente para uso em braquiterapia oftálmica de produção nacional foi desenvolvido no Laboratório de Produção de Fontes para Radioterapia do Instituto de Pesquisas Energéticas e Nucleares, de forma que o custo final da semente será menor do que o custo de importação de um modelo internacional, ampliando sua possibilidade de uso. Para que a semente possa ser usada de forma segura na prática clínica, foi realizada uma caracterização dosimétrica da mesma seguindo os protocolos do Task Group 43 da American Association of Physicists in Medicine. Neste trabalho o cálculo dosimétrico foi realizado por três vias diferentes: dosimetria termoluminescente, com filmes radiocrômicos, e por simulações de Monte Carlo; comparando-as para validar os resultados, que se mostraram compatíveis para a maioria dos pontos analisados. Também foram realizadas análises para além daquelas propostas pelo protocolo, como comparações com outras fontes comerciais, avaliação do efeito no perfil de dose da variação de parâmetros de produção da fonte, e estimativas de dose no olho humano. Seus resultados foram discutidos com base na aplicação clínica pretendida, embasando com dados a discussão a respeito do Irídio-192 ser utilizado de forma viável e segura como radioisótopo para o tratamento em braquiterapia oftálmica.

    Palavras-Chave: brachytherapy; iridium 192; monte carlo method; calculation methods; neutron transport theory; radiation doses; dose rates; dose equivalents; radiation dose ranges; thermoluminescent dosemeters; eyes; phase space; coordinated research programs; specifications; standards

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  • IPEN-DOC 29846

    AQUINO, S. ; LIMA, J.E.A.; BORRELY, S.I. . Combined application of gamma radiation, cleaning and chemical sanitizers in decontamination of vehicle air conditioning filters. Brazilian Journal of Radiation Sciences, v. 11, n. 2, p. 1-11, 2023. DOI: 10.15392/2319-0612.2023.2244

    Abstract: This work aimed to analyze the fungal contamination of air-conditioning filter waste (n=15) as an indicator of Quality Air Indoor from different car models in São Paulo city in São Paulo State, Brazil, during the period from October 2018 to July 2019. Three different treatments were used for the decontamination of car air conditioning filters, such as mechanical vacuum cleaning (I), vacuum cleaning and use of sanitizing product (II), and sanitizing product associated with radiation treatment at a dose of 17 kGy (III). After the treatments, microbiological analyses were performed and samples were plated in Petri dishes containing Sabouraud agar transferred by Swabs, and incubated for 7 days at 25 °C. The Petri dishes were stored in a standard Biochemical Oxygen Demand incubator, for the growth of fungal cultures. After incubation, the fungal cultures were evaluated, and the fungal counting was expressed in unit-forming colonies (UFC) and frequency in samples (%). The fungi were examined by lactophenol blue solution staining for microscopy. All samples of treatment I and II were contaminated with various fungal genera and high bioburden, namely (treatment I) Alternaria alternata, Aspergillus flavus, A. niger, Cladosporium spp., Fusarium spp., Mucor spp., Nigrospora spp., Not Sporulated Fungi (NSF), Penicillium spp., Rhizopus spp., Rhodotorula spp., Trichoderma spp. and yeasts. Treatment II showed Alternaria alternata, Aspergillus flavus, A. fumigatus, A. niger, A. ochraceus, Cladosporium spp., Mucor spp., NSF, Penicillium spp., Phoma spp., Rhizopus spp., Rhodotorula spp., Trichoderma spp., and yeasts. Treatment III presented NSF and yeasts, with 80% of material decontamination.

    Palavras-Chave: absorbed radiation doses; air conditioners; air conditioning; cryogenics; environmental quality; fungi; heating; indoor air pollution; irradiation; pollutants; radiation doses; vehicles

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  • IPEN-DOC 27201

    FREITAS, LUCAS F. de ; CRUZ, CASSIA P.C. da ; CAVALCANTE, ADRIANA K. ; BATISTA, JORGE G. dos S. ; VARCA, GUSTAVO H.C. ; MATHOR, MONICA B. ; LUGAO, ADEMAR B. . Comparison between gold nanoparticles synthesized by radiolysis and by EGCG-driven gold reduction. Radiation Physics and Chemistry, v. 174, p. 1-9, 2020. DOI: 10.1016/j.radphyschem.2020.108959

    Abstract: Radiolytic synthesis and phytochemical-driven gold reduction for the generation of nanoparticles are successful examples of Green Chemistry applied for nanomaterials. The present work compares these two green approaches focusing on hydrodynamic size, stability over time, optical properties and toxicity in NIH 3T3 (ATCC® CRL- 1658™) cells and Danio rerio (Zebra Fish). The radiolytic synthesis was performed by mixing 1 mM NaAuCl4; polyvinyl pyrrolidone 0.5%, AgNO3 6×10−5 M, propan-2-ol 0.2 M and acetone 0.06 M, followed by irradiation at 15 kGy (5 kGy h−1, 60Co source). The EGCG-functionalized nanoparticles were synthesized by mixing 1.6 mM of Au with 0.8 mM of EGCG in phosphate buffer (10 mM) for 2 h. Both methods yield the formation of gold nanoparticles featuring plasmon resonance bands at 520–530 nm, polydispersity above 0.3 was relevant only for the radiolytic protocol. Regarding stability over time, after 30 days, the nanoparticles synthesized radiolytically presented no relevant size changes, while some aggregation was observed for the EGCG-particles. The same nanoparticles demonstrated a lack of stability in high ionic strength medium. Slight toxicity was observed for the EGCG-nanoparticles in Danio rerio, with an IC50 calculated as 40.49%, while no IC50 was established within the concentration range of radiolysis-AuNPs used in this study. In conclusion, both green methods generated nanoparticles with good control of size and optical properties, especially via reduction by EGCG. However, the stability and toxicity results were found to be more promising for the radiolytically synthesized gold nanoparticles.

    Palavras-Chave: gold; nanoparticles; synthesis; chemistry; ecology; polyphenols; fishes

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  • IPEN-DOC 27622

    SOARES, CARLOS ; SANTANA, JULYANA ; GUVEN, OLGUN; MOURA, ESPERIDIANA A.B. . A comparison between graphene oxide and reduced graphene oxide as reinforcement agents in polypropylene nanocomposite using irradiated polypropylene as compatibilizer. In: LI, JIAN (Ed.); ZHANG, MINGMING (Ed.); LI, BOWEN (Ed.); MONTEIRO, SERGIO N. (Ed.); IKHMAYIES, SHADIA (Ed.); KALAY, YUNUS E. (Ed.); HWANG, JIANN-YANG (Ed.); ESCOBEDO-DIAZ, JUAN P. (Ed.); CARPENTER, JOHN S. (Ed.); BROWN, ANDREW D. (Ed.). Characterization of Minerals, Metals, and Materials. Cham, CZ, Switzerland: Springer Nature Switzerland AG, 2020. p. 385-394, (The Minerals, Metals & Materials Series). DOI: 10.1007/978-3-030-36628-5_36

    Abstract: Graphene is thematerial with the bestmechanical resistance ever encountered. Various types of studies have been carried out on possible applications. The use as a reinforcement in nanocomposites has shown to be a promising field, but some studies indicate that the graphene oxide (GO) and reduced graphene oxide (RGO) have better results as reinforcement, due to the functional groups,which allowa better adhesion with the matrix. This study analyzes the production of polypropylene (PP) nanocomposite comparing the use of graphene oxide (GO) and reduced graphene oxide (RGO) as fillers and irradiated polypropylene as a coupling agent.Atwin-screw extruder and injection molding machine were used to produce the nanocomposite PP reinforced with 0.2 wt% of GO and RGO by melt blending. The GO and RGO were characterized byXRDanalysis.The nanocomposite sampleswere characterized by XRD, SEM, TG, DSC and mechanical test.

    Palavras-Chave: graphene; oxides; polypropylene; nanocomposites; gamma radiation; stresses; tensile properties

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  • IPEN-DOC 29963

    SEPULBEDA, CAROLINA F.A. ; SANTIAGO, ELISABETE I. . Desenvolvimento de membranas poliméricas para aplicação em células combustível. In: PROGRAMA INSTITUCIONAL DE BOLSAS DE INICIAÇÃO CIENTÍFICA; SEMINÁRIO ANUAL PIBIC, 29.; SEMINÁRIO ANUAL PROBIC, 20.; SEMINÁRIO ANUAL PIBITI, 13., 23-24 de novembro, 2023, São Paulo, SP. Resumo expandido... São Paulo, SP: IPEN-CNEN/SP, 2023.

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  • IPEN-DOC 29201

    TEODORO, LARA E.H. ; TALACIMON, CRISTHIAN F. ; ROSERO, WILMMER A.A. ; RIGO, MARIA E.Z. ; RODRIGUES, PRISCILA S. ; NOGUEIRA, THUANY C. ; ANGELOCCI, LUCAS V. ; ROSTELATO, MARIA E.C.M. . Development of a new material to encapsulate phosphorus-32 for use in brachytherapy. In: BRAZIL MRS MEETING, 20th, September 25-29, 2022, Foz do Iguaçu, PR. Abstract... São Carlos, SP: Aptor Software, 2022.

    Abstract: The term cancer refers to a set of malignant diseases that have in common the disordered growth of mutated cells, which can invade adjacent tissues or distant organs[1]. In 2020, cancer of the central nervous system (CNS) represented 1.6% of all new malignant tumor cases in the world, and about 2.5% of all new cancer deaths[2]. A promising radioactive source for use in intracavitary brachytherapy is phosphorus-32. This source has been prominent as a minimally invasive treatment for craniopharyngiomas and in the treatment of metastatic bone diseases in general[3]. To encapsulate phosphorus-32 and make it a viable radioactive source for use in medicine, some methods have emerged. In this work, we are developing a fabric soaked in industrial latex for this purpose, as this source comes in the form of orthophosphoric acid in aqueous solution and as industrial latex is soluble in water. Tests carried out so far show that the material supports orthophosphoric acid while is still malleable, which is essential for treating spinal cancer.

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  • IPEN-DOC 30158

    ROSERO, WILMMER A.A. ; BARBEZAN, ANGELICA B. ; RIGO, MARIA E.Z. ; RODRIGUES, PRISCILA S. ; TEODORO, LARA E.H. ; TALACIMON, CRISTHIAN F. ; ZEITUNI, CARLOS A. ; ROSTELATO, MARIA E.C.M. . Development of radioactive nanoparticles functionalized with gum arabic to be used in nanobrachytherapy. In: BRAZIL MRS MEETING, 21st, October 1-5, 2023, Maceió, AL. Abstract... São Carlos, SP: Aptor Software, 2023. p. 553-553.

    Abstract: The development of new materials emerges as an alternative to the treatment of cancer, from the combination of nanotechnology and brachytherapy a new area of research was born, Nanobrachytherapy, which through the properties of nanometric materials can achieve better results in the fight against cancer. The objective of this work is classified as radiotherapy, which consists of the use of ionizing radiation to destroy or inhibit the growth of abnormal cells that form a tumor. [1] The ability to integrate NPsAu into biological systems is due to the nanometric dimensions of NPsAu probes which facilitate their incorporation into biological systems, as well as their bioconjugation and non-cytotoxic potential. [2] Taking into account the previous objective, gold was selected as the base element for obtaining nanometric systems, which due to its chemical richness and especially due to the intrinsic properties of one of its radioisotopes, which would allow us in theory to meet the stated objective. . Initially, it was based on the knowledge of the literature, and non-radioactive nanometric systems were obtained, and after a series of stability, characterization and application tests, the radioactive nanometric systems were obtained. Working with radioactive systems posed a great challenge, and up to now it presents us with situations to solve, but we have managed to create a methodology for obtaining, characterizing and applying radioactive gold nanoparticles, and also obtaining positive results from their application.

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  • IPEN-DOC 28665

    ANDRADE, MARCIO S. ; ISHIKAWA, OTAVIO H. ; COSTA, ROBSON S. ; SEIXAS, MARCUS V.S. ; RODRIGUES, RITA C.L.B.; MOURA, ESPERIDIANA A.B. . Development of sustainable food packaging material based on biodegradable polymer reinforced with cellulose nanocrystals. Food Packaging and Shelf Life, v. 31, p. 1-10, 2022. DOI: 10.1016/j.fpsl.2021.100807

    Abstract: The increased environmental impact and sustainability issues related to conventional food packaging have gained attention and led to a global concern. The massive consumption of conventional food packaging has increased disposal of non-eco-friendly packaging waste, severely damaging the environment. The replacement by sustainable packaging is an important alternative to reduce the enormous volume of plastic waste. In this work, bionanocomposite films composed of PBAT/PLA blend and cellulose nanocrystals (CNCs) extracted from agro-waste were investigated. Characterization of CNCs confirmed that nanocrystals were obtained. Bionanocomposite films presented better hydrophobic character and thermal stability than the blend film. In addition, the tensile strength, elongation at break, and Young's modulus was around 52%, 29%, and 118%, respectively, higher than blend films. These mechanical values were comparable to values of commercial plastic materials that are extensively used in food packaging. Thus, the prepared bionanocomposite films might be an interesting alternative to produce sustainable food packaging materials.

    Palavras-Chave: cellulose; nanocrystals; food; packaging; nanocomposites; sugar cane; bagasse; agricultural wastes

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  • IPEN-DOC 27887

    PRIMO, C.O. ; ANGELOCCI, L.V. ; KARAM JUNIOR, D.; ZEITUNI, C.A. ; ROSTELATO, M.E.C.M. . Dose-rate constant and air-kerma strength evaluation of a new 125I brachytherapy source using Monte-Carlo. Brazilian Journal of Radiation Sciences, v. 9, n. 1A, p. 1-11, 2021. DOI: 10.15392/bjrs.v9i1A.1441

    Abstract: Brachytherapy is a modality of radiotherapy which treats tumors using ionizing radiation with sources located close to the tumor. The sources can be produced from several radionuclides in various formats, such as Iodine-125 seeds and Iridium-192 wires. In order to produce a new Iodine-125 seed in IPEN/CNEN and ensure its quality, it is essential to describe the seed dosimetry, so when applied in a treatment the lowest possible dose to neighboring healthy tissues can be reached. The report by the AAPM’s Task Group 43 U1 is a document that indicates the dosimetry procedures in brachytherapy based on physical and geometrical parameters. In this study, dose-rate constant and air-kerma strength parameters were simulated using the Monte Carlo radiation transport code MCNP4C. The air-kerma strength is obtained from an ideal modeled seed, since its actual value should be measured for seeds individually in a specialized lab with a Wide-Angle Free-Air Chamber (WAFAC). Dose-rate constant and air-kerma strength are parameters that depends on intrinsic characteristics of the source, i.e. geometry, radionuclide, encapsulation, and together they define the dose-rate to the reference point. Radial dose function describes the dose fall-off with distance from the source. This study presents the values found for these parameters with associated statistical uncertainty, and is part of a larger project that aims the full dosimetry of this new seed model, including experimental measures.

    Palavras-Chave: brachytherapy; computerized simulation; dose rates; dosimetry; iodine 125; kerma; monte carlo method

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  • IPEN-DOC 29958

    OLIVEIRA, ANTONY A. de ; SAKATA, SOLANGE K. . Efeito de diferentes fontes de irradiação na redução do óxido de grafeno e aumento de escala. In: PROGRAMA INSTITUCIONAL DE BOLSAS DE INICIAÇÃO CIENTÍFICA; SEMINÁRIO ANUAL PIBIC, 29.; SEMINÁRIO ANUAL PROBIC, 20.; SEMINÁRIO ANUAL PIBITI, 13., 23-24 de novembro, 2023, São Paulo, SP. Resumo expandido... São Paulo, SP: IPEN-CNEN/SP, 2023.

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  • IPEN-DOC 29881

    BARROS, JANETTY J.P. ; OLIVEIRA, RENE R. ; LUNA, CARLOS B.B.; WELLEN, RENATE M.R.; MOURA, ESPERIDIANA A.B. . Effectiveness of modified lignin on poly(butylene adipateco-terephthalate)/poly(lactic acid) mulch film performance. Journal of Applied Polymer Science, v. 140, n. 46, p. 1-12, 2023. DOI: 10.1002/app.54684

    Abstract: In this work, the biodegradable poly(butylene adipate-co-terephthalate) (PBAT)/ poly(lactic acid) (PLA) blend (ECOVIO®) and lignin, a renewable and biodegradable natural polymer with high UV absorption and modified by gamma radiation were used to produce agriculture mulch films. Lignin was gammairradiated at 30 and 60 kGy. The irradiated and non-irradiated lignin content of 2 wt% was incorporated into PBAT/PLA blend matrix using a twin-screw extruder and extrusion blown film to prepare flexible films. PBAT/PLA/LIGNIN films were characterized by Fourier transform infrared (FTIR) spectroscopy, differential scanning calorimetry (DSC), x-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), tensile tests, contact angle, and UV–Vis analysis. FTIR spectra showed partial miscibility between PBAT/PLA and lignin, being intensified in irradiated lignin compounds. The DSC and XRD results confirmed that the degree of crystallinity of the blends was not significantly influenced by lignin addition. FE-SEM images showed better dispersion and miscibility in PBAT/PLA/Irradiated lignin. Miscibility improvement provided by irradiated lignin promoted better mechanical properties, mainly with lignin irradiated at 60 kGy. PBAT/PLA/LIGNIN films containing 2 wt% showed excellent UV-barrier property and greater hydrophobicity. Summing up, incorporation of low contents of irradiated lignin could be an interesting alternative to produce biodegradable UV-blocking agriculture mulch films.

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  • IPEN-DOC 26288

    ZDOROVETS, MAXIM; MASHENTSEVA, ANASTASSIYA; ANGNES, LUCIO; JACOVONE, RAYNARA M.S. ; SAKATA, SOLANGE K. . Electrochemical behaviour of track-etched membranes with embedded copper nanotubes. In: INTERNATIONAL NUCLEAR ATLANTIC CONFERENCE, October 21-25, 2019, Santos, SP. Proceedings... Rio de Janeiro: Associação Brasileira de Energia Nuclear, 2019. p. 2532-2537.

    Abstract: Track-etched membranes (TeMs) are thin polymer films with pores of various geometries made by irradiating on the DC-60 cyclotron and subsequent chemical etching. The objective of this work is to evaluate the electrochemical behavior of track-etched membranes with embedded copper nanotubes (TeMs/CuNT) using Cyclic Voltammetry. TeMs were prepared from 12.0 μm polyethylene terephthalate (PET) film by irradiation with 84Kr+15 on the DC-60 heavy ion accelerator. The irradiated film was etched in a basic solution followed by H2O2/UV system. The characterization was performed by scanning electron microscopy (SEM). For the electroless plating consists of three successive stages: sensitization, activation and directly deposition. The electrochemical studies was performed in two different media KOH and Na2SO4 adding adding 100uL aliquots of nitrate solution using Pt as counter electrode, Ag/AgI as reference and the copper as work electrode. The results showed the potential of TeMs/CuNT as nitrate sensor in sodium sulfate medium.

    Palavras-Chave: copper; electrochemistry; electrolytes; etching; films; gamma radiation; heavy ion accelerators; irradiation; nanotubes; nitrates; scanning electron microscopy; sodium sulfates; water

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  • IPEN-DOC 29057

    BARROS, JANETTY J.P. ; SOARES, CARLOS P. ; MOURA, ESPERIDIANA A.B. de ; WELLEN, RENATE M.R.. Enhanced miscibility of PBAT/PLA/lignin upon γ-irradiation and effects on the non-isothermal crystallization. Journal of Applied Polymer Science, v. 139, n. 45, p. 1-18, 2022. DOI: 10.1002/app.53124

    Abstract: Lignin is natural and renewable polymer, the second most abundant on Earth. Properly used it can reduce synthetic and oil based materials in addition to contributing to the biodegradable systems. In this work, the kraft lignin was subjected to gamma radiation at absorbed doses of 30, 60, and 90 KGy in order to increase the interaction with “Poly(butylene adipate-co-terephthalate) (PBAT)/Poly(lactic acid) (PLA)” blend (Ecovio®). PBAT/PLA/lignin blends with 10% of the weight of lignin were produced by extrusion using twin-screw extruder and characterized by Fourier transform infrared spectroscopy (FTIR), Differential scanning calorimetry (DSC), and Field emission scanning electron microscopy (FE-SEM). FTIR spectra showed partial miscibility between PBAT/PLA and lignin, most due to the hydrogen bond between PBAT/PLA carbonyl and lignin hydroxyl, being intensified in irradiated lignin compounds. As evidenced on DSC scans, in PBAT/PLA/irradiated lignin the crystallization peak was shifted to lower temperatures and the crystallization rate decreased. Crystallization kinetics was modeled using Pseudo Avrami, and isoconversional models of Friedman and Vyazovkin. Pseudo-Avrami displayed linearity deviation at beginning and crystallization ending due to the nucleation and secondary crystallization, while from Friedman and Vyazovkin the activation energy (Ea) was higher for PBAT/PLA/irradiated lignin 30 KGy, characterizing crystallization with higher energy consumption. FE-SEM images showed better dispersion and miscibility in PBAT/PLA/irradiated lignin. The results indicate that the irradiation of Kraft lignin promotes miscibility and compatibility of PBAT/PLA/lignin.

    Palavras-Chave: crystallization; polymers; calorimetry; irradiation; kinetics

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  • IPEN-DOC 29064

    BARBOSA, ANDREY S. ; BIANCOLLI, ANA L.G. ; LANFREDI, ALEXANDRE J.C.; RODRIGUES JUNIOR, ORLANDO ; FONSECA, FABIO C. ; SANTIAGO, ELISABETE I. . Enhancing the durability and performance of radiation-induced grafted low-density polyethylene-based anion-exchange membranes by controlling irradiation conditions. Journal of Membrane Science, v. 659, p. 1-12, 2022. DOI: 10.1016/j.memsci.2022.120804

    Abstract: This study presents a systematic analysis of the influence of irradiation conditions (absorbed dose, temperature, and atmosphere) on the physicochemical properties of radiation-induced grafted anion-exchange membranes (AEMs) based on low-density polyethylene (LDPE). Detailed characterization of the polymeric electrolytes shows striking effects of the irradiation conditions on the AEM properties. The LDPE films are irradiated both at room temperature (RT) and low temperature (LT, ∼ −10 °C). At each temperature, samples are irradiated in air as well as nitrogen. By lowering the sample temperature from RT to LT during irradiation in air it is possible to obtain a threefold increase in the degree of grafting (DoG). The higher DoG reflects in the OH− conductivity (σ) of the AEM irradiated at LT, which exhibits σ (T = 80 °C) = 215 mS cm−1, while the sample prepared at RT and air has σ (T = 80 °C) = 127 mS cm−1. Such high conductivity of the LT irradiated LDPE-AEM results in high-performance anion-exchange membrane fuel cell (AEMFC) with enhanced stability, as inferred from the time dependence of σ (T = 60 °C) measurements. The experimental results evidence that the control of both the irradiation temperature and the atmosphere diminishes the degradation effects caused by the radiation. Therefore, the present study advances the understanding of the role played by the irradiation process on the final properties of radiation-induced grafted LDPE-based AEMs and offers new possibilities to guide future developments for anion-exchange membranes.

    Palavras-Chave: polyethylenes; density; anions; ion exchange; membranes; fuel cells

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  • IPEN-DOC 28392

    CHMIELEWSKI, ANDRZEJ G.; HAN, BUMSOO; SABHARWAL, SUNIL; SAMPA, MARIA H. . Environmental protection: reducing environmental pollution. In: GREENSPAN, EHUD (Ed.). Encyclopedia of nuclear energy. Amsterdam: Elsevier, 2021. p. 520-526, v. 4, DOI: 10.1016/B978-0-12-409548-9.12331-0

    Palavras-Chave: water treatment; environmental protection; ionizing radiations; flue gas; electron beams; gamma radiation

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