Terahertz Spectroscopy for Characterization of Hydrogen Bonding and Cross-linked Structure Dynamics in Polyurethane

Hoshina, Hiromichi; Saito, Yuichi; Furuhashi, Takumi; Shimazaki, Tomomi; Sawada, Manabu; Hioki, Yasunori; Otani, Chiko

doi:10.1007/s10762-019-00667-0

Cited by 17 publications

(6 citation statements)

References 23 publications

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“…Sukumaran et al research the H-bonded interactions between −CO and OH/NH functional groups within PHUs using temperature-dependent FTIR [141]. However, some more studies have been done on polyurethanes [142,143] and compounds that can be used as bio-based cyclic carbonates precursors for BPHU synthesis (Figure 6, right circle). The THz time-domain spectrometer was used to verify the THz properties of lignin, including refractive indices and absorption coefficients.…”

Section: Bio-based Polyhydroxyurethane (Bphu)mentioning

confidence: 99%

Review of Bioplastics Characterisation by Terahertz Techniques in the View of Ensuring a Circular Economy

Abina,

Korošec,

Puc

et al. 2023

Photonics

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The increasing scarcity of natural resources, worsening global climate change, environmental degradation, and rising demand for food are forcing the biotechnology and plastics industries to seek and apply circular economy models that would lead to a sustainable transition in the production and use of bioplastics. Circular economy models can improve the economic productivity of bio-based plastics and have a positive impact on the environment by reducing conventional plastic waste and the consumption of petrochemical feedstocks for plastic production. In addition, some agricultural wastes that have the potential to be used as bioplastics can be reused. Terahertz (THz) systems are already used in the plastics and rubber industries for non-destructive testing, detection, imaging, and quality control. Several reports have highlighted the potential applications of THz spectroscopy and imaging in polymer analysis and plastics characterisation. This potential is even greater with chemometric methods and artificial intelligence algorithms. In this review, we focus on applications that support the transformation of the biotechnology sector to the circular economy, particularly via the transition from conventional plastics to bioplastics. In this review, we discuss the potential of THz systems for the characterisation and analysis of bioplastics and biopolymers. The results of previous studies on biopolymers in the THz frequency range are summarised. Furthermore, the potential of using artificial intelligence approaches such as machine learning as advanced analytical methods in THz spectroscopy and imaging, in addition to the conventionally used chemometric methods, is discussed. The results of this review highlight that THz technology can contribute to closed technological circles in important areas of biotechnology and the related plastics and rubber industries.

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Section: Bio-based Polyhydroxyurethane (Bphu)mentioning

confidence: 99%

Review of Bioplastics Characterisation by Terahertz Techniques in the View of Ensuring a Circular Economy

Abina,

Korošec,

Puc

et al. 2023

Photonics

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“…Terahertz time-domain spectroscopy (THz-TDS) is a powerful contact-free, all-optical nondestructive method to probe low-frequency IR-active vibrations, charge transport, and dielectric relaxations in many material systems, including inorganic solids and polymeric materials. − This is accomplished by analyzing the complex-valued transmission spectra obtained from measuring time-dependent electric fields of THz light pulses transmitted through the material of interest. , Here, we apply THz-TDS, within the frequency range of 0.1–7 THz (3–233.5 cm –1 ), to study the conduction properties of PEO-based electrolytes with samples containing Li + salts, including lithium difluoro(oxalato)borate (LiDFOB), lithium bis(trifluoromethanesulfonyl)imide (LiTFSI), and their mixture, at controlled temperatures, ranging from 10 to 300 K. Compared with the bare polymer without any salts, highly distinguishable THz conductivity spectra were obtained from the electrolyte samples with salts, which are found to depend strongly on the content and type of the added salt for the same oxide-to-Li + ratio. The experimental THz conductivity spectra are well reproduced by a Lorentzian model accounting for temperature- and salt-dependent resonant vibration modes.…”

Section: Introductionmentioning

confidence: 99%

Fundamental Picture of the Conduction Mechanism in Solid-State Polymer Electrolytes Revealed by Terahertz Spectroscopy

Weidelt,

Nair,

Diddens

et al. 2024

J. Phys. Chem. C

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Solid polymer electrolytes (SPEs) based on cross-linked poly(ethylene oxide) encompassing lithium salts have gained significant attention as separators in solid-state lithium metal batteries. Here, we employ terahertz time-domain spectroscopy (THz-TDS), as a noninvasive contact-free technique, to investigate the conduction properties of these cross-linked SPEs and unravel their dependencies on the added lithium salt and the sample temperature. The obtained THz conductivity spectra are dominated by THz absorption bands, which we attribute to resonant vibrations within the polymer matrix of the electrolyte. By careful application of the Lorentz model, the conductivity spectra have been analyzed, and the relevant polymer vibration modes have been quantitatively assessed. Calculations based on density functional theory were performed to elucidate the possible microscopic mechanisms of these resonant vibrations. This study sheds light on the relevance of polymer matrix vibrations validating the hopping transport of lithium ions in SPEs which ultimately leads to the technologically relevant ionic conduction in solid-state polymer-based electrolytes.

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“…Furthermore, in many systems, crystallization is accompanied by the formation of specific interactions or conformational transitions. Polymers are interesting targets as their low-frequency vibrational intensity can reflect sharply the interchain interactions − and higher-order conformations , of polymers. For example, Funaki et al demonstrated that poly(ε-caprolactone) (PCL) forms three weak intermolecular C–H···OC hydrogen bonds between CH 2 and CO groups combining THz spectroscopy, IR, and quantum chemical calculations .…”

Section: Introductionmentioning

confidence: 99%

Study of Crystallinity and Conformation of Poly(lactic acid) by Terahertz Spectroscopy

et al. 2022

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During crystallization, conformational changes are often accompanied by the formation of interactions. Terahertz (THz) spectroscopy exhibits strong responses to the crystalline poly(lactic acid) (PLA). Therefore, we estimate the relative crystallinity and investigate the effect of conformational transition on the vibration of PLA by THz spectroscopy. By comparing with the results of X-ray diffraction (XRD) and differential scanning calorimetry (DSC), the validity of THz spectroscopy to calculate crystallinity is verified. Furthermore, the peak intensity of PLA at 2.01 THz increases with crystallinity. Combined with Fourier transform infrared spectroscopy (FTIR), the vibrational intensity of PLA at 2.01 THz is highly correlated with the contribution of gt conformation, showing a linear relationship. In addition, the vibrational peak of PLA also reflects the interchain interactions. We believe that the increase in peak intensity with increasing crystallinity originates from the effect of the dipole−dipole interactions between the carbonyl groups. Our study demonstrates the ability of THz spectroscopy to estimate the crystallinity of PLA, and the peak at 2.01 THz shows conformational and interaction sensitivities.

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Terahertz Spectroscopy for Characterization of Hydrogen Bonding and Cross-linked Structure Dynamics in Polyurethane

Cited by 17 publications

References 23 publications

Review of Bioplastics Characterisation by Terahertz Techniques in the View of Ensuring a Circular Economy

Review of Bioplastics Characterisation by Terahertz Techniques in the View of Ensuring a Circular Economy

Fundamental Picture of the Conduction Mechanism in Solid-State Polymer Electrolytes Revealed by Terahertz Spectroscopy

Study of Crystallinity and Conformation of Poly(lactic acid) by Terahertz Spectroscopy

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