Caracterização de géis termorreversíveis de SEBS

Carvalho, Antônio J. F.

doi:10.1590/s0104-14282000000100003

Cited by 4 publications

(5 citation statements)

References 8 publications

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“…Notably, the sample containing SBS had the lowest attenuation value (4.11 ± 0.11 dB•cm -1 at 5 MHz, Figure 2B), but as SBS is more susceptible to degradation at high temperatures and more prone to oxidation in the absence of antioxidants [48], we chose to focus on high MW SEBS as our base polymer. It is known that SEBS samples with low polymer concentrations are susceptible to plastic deformation [66]. Therefore, we aimed to strengthen the mechanical stability of the material by addition of a second polymer, which could also further improve the acoustic properties.…”

Section: A Systematic Optimisation Of Copolymer-in-oil Materials Results In High Speed Of Soundmentioning

confidence: 99%

A Copolymer-in-Oil Tissue-Mimicking Material With Tuneable Acoustic and Optical Characteristics for Photoacoustic Imaging Phantoms

Hacker

Joseph

Ivory

et al. 2021

IEEE Trans. Med. Imaging

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Photoacoustic imaging (PAI) standardisation demands a stable, highly reproducible physical phantom to enable routine quality control and robust performance evaluation. To address this need, we have optimised a lowcost copolymer-in-oil tissue-mimicking material formulation. The base material consists of mineral oil, copolymer and stabiliser with defined Chemical Abstract Service numbers. Speed of sound c(f) and acoustic attenuation coefficient α(f) were characterised over 2-10 MHz; optical absorption µa(ʎ) and reduced scattering µs'(ʎ) coefficients over 450-900 nm. Acoustic properties were optimised by modifying base component ratios and optical properties were adjusted using additives. The temporal, thermomechanical-and photo-stability were studied, along with intra-laboratory fabrication and field-testing. c(f) could be tuned up to (1516±0.6)m•s -1 and α(f) to (17.4±0.3)dB•cm -1 at 5MHz. The base material exhibited negligible µa(ʎ) and µs'(ʎ), which could be independently tuned by addition of Nigrosin or TiO2 respectively. These properties were stable over almost a year and were minimally affected by recasting. The material showed high intra-laboratory reproducibility (coefficient of variation <4% for c(f), α(f), optical transmittance and reflectance), and good photoand mechanical-stability in the relevant working range. The optimised copolymer-in-oil material represents an excellent candidate for widespread application in PAI phantoms, with properties suitable for broader use in biophotonics and ultrasound imaging standardisation efforts.

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Section: A Systematic Optimisation Of Copolymer-in-oil Materials Results In High Speed Of Soundmentioning

confidence: 99%

A Copolymer-in-Oil Tissue-Mimicking Material With Tuneable Acoustic and Optical Characteristics for Photoacoustic Imaging Phantoms

Hacker

Joseph

Ivory

et al. 2021

IEEE Trans. Med. Imaging

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“…Dentre as vantagens do elastômero termoplástico em relação à borracha convencional, observam-se custos energéticos menores, ciclos mais rápidos de processamento, baixos índices de desperdícios e peças totalmente recicláveis. Além disso, devido a sua saturação, são resistentes à oxidação e ao ozônio, apresentando boa resistência a altas temperaturas [7,24].…”

Section: Introductionunclassified

Influência da adição de resíduo de pneu em matriz de SEBS para aplicação em pisos industriais

2022

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RESUMO O descarte inadequado de pneus representa um grave problema ambiental, pois seu elevado tempo de decomposição, aliado ao seu descarte incorreto, o torna uma grande ameaça aos recursos naturais, causando contaminação de solos e rios, além de enfermidades provocadas pelo acúmulo de resíduos e água em seu interior, proliferando vírus e bactérias. Dentre as alternativas possíveis de reutilização deste resíduo é possível optar por sua incorporação em outros materiais, o que além de torná-lo um resíduo economicamente atrativo, possibilita que sejam desenvolvidas novas composições de materiais com propriedades diferenciadas. A proposta deste trabalho consiste na adição de resíduo de pneu em matriz de elastômero termoplástico SEBS (copolímero de estireno - etileno/butileno - estireno). Em um primeiro momento avaliou-se a influência do tamanho de grão do resíduo. Foram utilizados grãos de tamanhos de 12, 24 e 35 mesh. Após a realização de ensaios físicos, térmicos e mecânicos, que permitiram a escolha da melhor granulometria, variou-se a concentração de resíduo em 10, 20 e 30% em massa de SEBS. Os resultados mostraram que o composto desenvolvido com granulometria de 12 mesh, em concentração de 10% em massa de SEBS, mostrou-se a composição com melhores propriedades mecânicas, o que sugere sua vantagem em aplicação em pisos industriais.

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“…The maleic anhydride functionalization process of SEBS and EPDM makes the molecular structure more reactive. [45] Therefore, developing PP with SEBS grafted with maleic anhydride (SEBS-MA) and EPDM grafted with maleic anhydride (EPDM-MA) may make the mixture more polar, helping to increase the surface interaction with the CF residue. In view of this, it becomes of great importance to evaluate PP/CF composites compatibilized with SEBS-MA and EPDM-MA, considering that there are practically no reports in the literature of polymeric composites.…”

Section: Introductionmentioning

confidence: 99%

Reuse of carbon fiber waste to produce composites with polypropylene. The effect of styrene‐(ethylene‐butylene)‐styrene grafted with maleic anhydride and ethylene‐propylene‐diene grafted with maleic anhydride copolymers

et al. 2021

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Carbon fiber (CF) is a difficult material to recycle, generating accumulation and environmental impacts when disposed of incorrectly. The practice of reuse is being encouraged, aiming to minimize socio-environmental impacts. The present research aimed to develop polypropylene (PP) composites with CF waste, using styrene-(ethylene-butylene)-styrene grafted with maleic anhydride (SEBS-MA) and ethylene-propylene-diene grafted with maleic anhydride (EPDM-MA), as compatibilizers. The composites were processed in a mixer and injection molded. The addition of the CF in the PP matrix did not hinder processability, as verified in torque rheometry. Significant increases were achieved in impact strength and elongation at break, especially in the PP/FC/ SEBS-MA and PP/FC/EPDM-MA composites. Incorporating 15% EPDM-MA reduced the elastic modulus and tensile strength by 23% and 32%, while SEBS-MA by 13% and 23%, relative to PP, respectively, due to the increase in flexibility of the composites. When the PP/FC composites were compatibilized with SEBS-MA and EPDM-MA, there was a higher level of interaction among the phases, generating a higher wettability, as verified in the scanning electron microscopy. Such behavior was important to increase the crystallinity of the compatibilized composites. The composites thermal stability increased significantly, increasing in 40 C, compared to pure PP. In general, the compatibilization with SEBS-MA was more effective, generating better properties.As a consequence, the heat deflection temperature of the composites remained the same as the level of pure PP, suggesting good structural stability. The results are valuable for the recycling area, since CF can be reused as a polymer additive to improve properties.

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Caracterização de géis termorreversíveis de SEBS

Cited by 4 publications

References 8 publications

A Copolymer-in-Oil Tissue-Mimicking Material With Tuneable Acoustic and Optical Characteristics for Photoacoustic Imaging Phantoms

A Copolymer-in-Oil Tissue-Mimicking Material With Tuneable Acoustic and Optical Characteristics for Photoacoustic Imaging Phantoms

Influência da adição de resíduo de pneu em matriz de SEBS para aplicação em pisos industriais

Reuse of carbon fiber waste to produce composites with polypropylene. The effect of styrene‐(ethylene‐butylene)‐styrene grafted with maleic anhydride and ethylene‐propylene‐diene grafted with maleic anhydride copolymers

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