Time-Domain NMR Techniques in Cellulose Structure Analysis

Grunin, Leonid; Ivanova, Maria; Schiraya, Veronika; Grunina, Tatiana

doi:10.1007/s00723-023-01600-4

Cited by 6 publications

(2 citation statements)

References 96 publications

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“…The CPMG pulse sequence enables the measurement of long T 2 relaxation times, allowing the analysis of the long components (liquid-like) of polymers [ 28 , 49 , 50 , 51 ]. DQ, MSE, and SE have short T 2 relaxation times and are thus suitable for analysis of the rigid components (solid-like) of polymers [ 52 , 53 , 54 ]. The data after the middle region of each transitional curve includes data related to highly motile components.…”

Section: Discussionmentioning

confidence: 99%

Designing Sustainable Hydrophilic Interfaces via Feature Selection from Molecular Descriptors and Time-Domain Nuclear Magnetic Resonance Relaxation Curves

Okada,

Amamoto,

Kikuchi

2024

Polymers

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Surface modification using hydrophilic polymer coatings is a sustainable approach for preventing membrane clogging due to foulant adhesion to water treatment membranes and reducing membrane–replacement frequency. Typically, both molecular descriptors and time–domain nuclear magnetic resonance (TD–NMR) data, which reveal physicochemical properties and polymer–chain dynamics, respectively, are required to predict the properties and understand the mechanisms of hydrophilic polymer coatings. However, studies on the selection of essential components from high–dimensional data and their application to the prediction of surface properties are scarce. Therefore, we developed a method for selecting features from combined high–dimensional molecular descriptors and TD–NMR data. The molecular descriptors of the monomers present in polyethylene terephthalate films were calculated using RDKit, an open–source chemoinformatics toolkit, and TD–NMR spectroscopy was performed over a wide time range using five–pulse sequences to investigate the mobility of the polymer chains. The model that analyzed the data using the random forest algorithm, after reducing the features using gradient boosting machine–based recursive feature elimination, achieved the highest prediction accuracy. The proposed method enables the extraction of important elements from both descriptors of surface properties and can contribute to the development of new sustainable materials and material–specific informatics methodologies encompassing multiple information modalities.

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Section: Discussionmentioning

confidence: 99%

Designing Sustainable Hydrophilic Interfaces via Feature Selection from Molecular Descriptors and Time-Domain Nuclear Magnetic Resonance Relaxation Curves

Okada,

Amamoto,

Kikuchi

2024

Polymers

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“…In addition, the role of entanglements in network properties has been discussed [10][11][12][13][14]. Other examples of the versatility of MQ-NMR experiment include its use in unveiling molecular details across a range of polymeric materials [15,16], such as swollen gels [17,18], nanocomposites [19], polymer melts [20], and rubber blends [21]. Finally, it should be noted that the unique quantitative information from MQ-NMR experiments has been crucial in determining the degree of devulcanization in several types of rubber, leading to enhanced molecular characterization of recycled rubbers through this powerful technique [22][23][24].…”

Section: Introductionmentioning

confidence: 99%

Introducing “MEW2” Software: A Tool to Analyze MQ-NMR Experiments for Elastomers

Salamanca,

Zepeda-Rodríguez,

Diñeiro

et al. 2023

Polymers

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Low-field time-domain proton Nuclear Magnetic Resonance (NMR) spectroscopy is an attractive and powerful tool for studying the structure and dynamics of elastomers. The existence of crosslinks and other topological constraints in rubber matrices (entanglements and filler–rubber interactions, among others) renders the fast segmental fluctuations of the polymeric chains non-isotropic, obtaining nonzero residual dipolar couplings, which is the main observable of MQ-NMR experiments. A new software, Multiple quantum nuclear magnetic resonance analyzer for Elastomeric Networks v2 (MEW2), provides a new tool to facilitate the study of the molecular structure of elastomeric materials. This program quantitatively analyzes two different sets of experimental data obtained in the same experiment, which are dominated by multiple-quantum coherence and polymer dynamics. The proper quantification of non-coupled network defects (dangling chain ends, loops, etc.) allows the analyzer to normalize the multiple quantum intensity, obtaining a build-up curve that contains the structural information without any influence from the rubber dynamics. Finally, it provides the spatial distribution of crosslinks using a fast Tikhonov regularization process based on a statistical criterion. As a general trend, this study provides an automatic solution to a tedious procedure of analysis, demonstrating a new tool that accelerates the calculations of network structure using 1H MQ-NMR low-field time-domain experiments for elastomeric compounds.

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Investigating the crystallinity of hard candies prepared and stored at different temperatures with low field‐NMR relaxometry

Kuzu,

Ozel,

Uguz

et al. 2024

J Sci Food Agric

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BackgroundIn this study, hard candies were produced by using sucrose, glucose syrup and water. They were cooked at different temperatures, changing from 135 to 145 °C with an interval of 2.5 °C. They were stored at different storage temperatures, which were 25, 4, −18 and −80 °C. Hard candies placed at room temperature were stored for 2 months. In order to understand the crystallization characteristics of the hard candies, time domain (TD) proton nuclear magnetic resonance (1H‐NMR) parameters of longitudinal relaxation time (T1) and second moment (M2) measurements were conducted. Moisture contents of the hard candies were determined by Karl–Fischer titration. X‐ray diffraction experiments were also conducted as the complementary analysis.ResultsIncreasing cooking temperature increased the crystallinity and decreased the moisture content of the hard candies significantly (P ≤0.05). Furthermore, storage temperature and storage time had significant effects on the crystallinity of the hard candies (P ≤0.05). The results of T1 and M2 correlated with each other (r > 0.8, P ≤ 0.5) and both produced the highest value at the cooking temperature of 145 °C and storage temperature of 4 °C (P ≤ 0.05). The values of T1 and M2 were obtained as 245.9 ms and 13.0 × 10−8 Hz2, respectively, for the cooking temperature of 145 °C and storage temperature of 4 °C.ConclusionThis study demonstrated that the crystallinity of hard candies can be observed and examined by TD‐NMR relaxometry, as an alternative to commonly used methods. © 2024 The Author(s). Journal of the Science of Food and Agriculture published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.

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Time-Domain NMR Techniques in Cellulose Structure Analysis

Cited by 6 publications

References 96 publications

Designing Sustainable Hydrophilic Interfaces via Feature Selection from Molecular Descriptors and Time-Domain Nuclear Magnetic Resonance Relaxation Curves

Designing Sustainable Hydrophilic Interfaces via Feature Selection from Molecular Descriptors and Time-Domain Nuclear Magnetic Resonance Relaxation Curves

Introducing “MEW2” Software: A Tool to Analyze MQ-NMR Experiments for Elastomers

Investigating the crystallinity of hard candies prepared and stored at different temperatures with low field‐NMR relaxometry

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