Caracterização de géis termorreversíveis de SEBS

Carvalho, Antônio J. F.

doi:10.1590/s0104-14282000000100003

Cited by 4 publications

(4 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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“…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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“…Gels of the styrene-ethylene/butylene-styrene copolymer, better known as SEBS gels, comprise a class of thermoreversible gels with a large number of applications in the industry, for example, as sealants, wire coatings and insulation, medical and pharmaceutical parts (Walker 1989, Carvalho 2000, Kim et al 2006. One interesting property is that SEBS gels do not require the process of vulcanization in the production.…”

Section: Introductionmentioning

confidence: 99%

“…In the present paper we propose SEBS as a TMM for ultrasound, optical techniques and photoacoustics. Low-density polyethylene (LDPE) was added to SEBS to improve its mechanical stability, since it is known that SEBS gels can lose shape depending on the formulation used (Carvalho 2000). Therefore, in this paper, the SEBS/LDPE blends were investigated.…”

Section: Introductionmentioning

confidence: 99%

Stable phantom materials for ultrasound and optical imaging

et al. 2016

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Phantoms mimicking the specific properties of biological tissues are essential to fully characterize medical devices. Water-based materials are commonly used to manufacture phantoms for ultrasound and optical imaging techniques. However, these materials have disadvantages, such as easy degradation and low temporal stability. In this study, we propose an oil-based new tissue-mimicking material for ultrasound and optical imaging, with the advantage of presenting low temporal degradation. A styrene-ethylene/butylene-styrene (SEBS) copolymer in mineral oil samples was made varying the SEBS concentration between 5%-15%, and low-density polyethylene (LDPE) between 0%-9%. Acoustic properties, such as the speed of sound and the attenuation coefficient, were obtained using frequencies ranging from 1-10 MHz, and were consistent with that of soft tissues. These properties were controlled varying SEBS and LDPE concentration. To characterize the optical properties of the samples, the diffuse reflectance and transmittance were measured. Scattering and absorption coefficients ranging from 400 nm-1200 nm were calculated for each compound. SEBS gels are a translucent material presenting low optical absorption and scattering coefficients in the visible region of the spectrum, but the presence of LDPE increased the turbidity. Adding LDPE increased the absorption and scattering of the phantom materials. Ultrasound and photoacoustic images of a heterogeneous phantom made of LDPE/SEBS containing a spherical inclusion were obtained. Annatto dye was added to the inclusion to enhance the optical absorbance. The results suggest that copolymer gels are promising for ultrasound and optical imaging, making them also potentially useful for photoacoustic imaging.

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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

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

Stable phantom materials for ultrasound and optical imaging

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