Polyurethane and rare-earth materials: a review

Pegoraro, Guilherme Manassés; Alves, Lucas Repecka; Carriello, Giovanni Miraveti; Janolla, Thais de Agrella; Mambrini, G. P.; Rezende, Maira de Lourdes; Menezes, Aparecido Júnior de

doi:10.18540/jcecvl9iss3pp15627-01e

Cited by 3 publications

(1 citation statement)

References 104 publications

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“…PU foams are synthesized through a two-step process known as gelling and blowing reactions [2,5] . To facilitate this synthesis, two primary reagents are required: isocyanates and polyols [6,7] .…”

Section: Introductionmentioning

confidence: 99%

Green polyurethane foams: Replacing petrochemical polyol with castor oil through factorial design

Alves,

Carriello,

Pegoraro

et al. 2024

Preprint

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Polyurethanes are renowned for their incredible versatility. They are available in various forms, such as foams, thermoplastics, elastomers, and paints. These polymers are synthesized from two chemical substances: isocyanates and polyols. The increasing interest in the utilization of materials from renewable sources has spurred significant research in search of replacements for these two substances. For instance, castor oil can be used as a substitute for polyol, in addition to being an abundant renewable source. In this context, the objective of this study is to investigate how the variables temperature (2°C, 24°C, and 70°C) and mass ratio (2:1, 1:1, and 1:2) influence the final properties of polyurethane foams. The foams were prepared using the one-shot method under controlled agitation. The results indicated that replacing polyol with vegetable oil was successful, as evidenced by the appearance of reference bands in the FTIR spectra. XRD and DSC analyses confirmed the amorphous nature of the polyurethanes, and TG tests demonstrated that a temperature of 70°C significantly reduced the thermal stability of the foams, especially those based on vegetable sources. However, synthesis temperatures of 2°C and 24°C did not show considerable alteration in thermal stability.

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Section: Introductionmentioning

confidence: 99%

Green polyurethane foams: Replacing petrochemical polyol with castor oil through factorial design

Alves,

Carriello,

Pegoraro

et al. 2024

Preprint

Self Cite

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Synthesis and characterization of polyurethane and samarium(III) oxide and holmium(III) oxide composites

Alves,

Carriello,

Pegoraro

et al. 2023

Polímeros

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Development of Fiber-Bragg-Grating-Integrated Artificial Embedded Tendon for Multifunctional Assessment of Temperature, Strain, and Curvature

Pires-Junior,

Frizera,

Marques

et al. 2023

Sensors

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This paper presents the development and application of an optical fiber-embedded tendon based on biomimetic multifunctional structures. The tendon was fabricated using a thermocure resin (polyurethane) and the three optical fibers with one fiber Bragg grating (FBG) inscribed in each fiber. The first step in the FBG-integrated artificial tendon analysis is the mechanical properties assessment through stress–strain curves, which indicated the customization of the proposed device, since it is possible to tailor the Young’s modulus and strain limit of the tendon as a function of the integrated optical fibers, where the coated and uncoated fibers lead to differences in both parameters, i.e., strain limits and Young’s modulus. Then, the artificial tendon integrated with FBG sensors undergoes three types of characterization, which assesses the influence of temperature, single-axis strain, and curvature. Results show similarities in the temperature responses in all analyzed FBGs, where the variations are related to the heterogeneity on the polyurethane matrix distribution. In contrast, the FBGs embedded in the tendon presented a reduction in the strain sensitivity when compared with the bare FBGs (i.e., without the integration in the artificial tendon). Such results demonstrated a reduction in the sensitivity as high as 77% when compared with the bare FBGs, which is related to strain field distributions in the FBGs when embedded in the tendon. In addition, the curvature tests indicated variations in both optical power and wavelength shift, where both parameters are used on the angle estimation using the proposed multifunctional artificial tendon. To that extent, root mean squared error of around 3.25° is obtained when both spectral features are considered. Therefore, the proposed approach indicates a suitable method for the development of smart structures in which the multifunctional capability of the device leads to the possibility of using not only as a structural element in tendon-driven actuators and devices, but also as a sensor element for the different structures.

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Polyurethane and rare-earth materials: a review

Cited by 3 publications

References 104 publications

Green polyurethane foams: Replacing petrochemical polyol with castor oil through factorial design

Green polyurethane foams: Replacing petrochemical polyol with castor oil through factorial design

Synthesis and characterization of polyurethane and samarium(III) oxide and holmium(III) oxide composites

Development of Fiber-Bragg-Grating-Integrated Artificial Embedded Tendon for Multifunctional Assessment of Temperature, Strain, and Curvature

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