1
|
Esfahani G, Trutschel ML, Reichert D, Mäder K. Characterization of Controlled Release Starch-Nimodipine Implant for Antispasmodic and Neuroprotective Therapies in the Brain. Mol Pharm 2023; 20:5753-5762. [PMID: 37750866 DOI: 10.1021/acs.molpharmaceut.3c00618] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 09/27/2023]
Abstract
Parenteral depot systems can provide a constant release of drugs over a few days to months. Most of the parenteral depot products on the market are based on poly(lactic acid) and poly(lactide-co-glycolide) (PLGA). Studies have shown that acidic monomers of these polymers can lead to nonlinear release profiles or even drug inactivation before release. Therefore, finding alternatives for these polymers is of great importance. Our previous study showed the potential of starch as a natural and biodegradable polymer to form a controlled release system. Subarachnoid hemorrhage (SAH) is a life-threatening type of stroke and a major cause of death and disability in patients. Nimotop® (nimodipine (NMD)) is an FDA-approved drug for treating SAH-induced vasospasms. In addition, NMD has, in contrast to other Ca antagonists, unique neuroprotective effects. The oral administration of NMD is linked to variable absorption and systemic side effects. Therefore, the development of a local parenteral depot formulation is desirable. To avoid the formation of an acidic microenvironment and autocatalytic polymer degradation, we avoided PLGA as a matrix and investigated starch as an alternative. Implants with drug loads of 20 and 40% NMD were prepared by hot melt extrusion (HME) and sterilized with an electron beam. The effects of HME and electron beam on NMD and starch were evaluated with NMR, IR, and Raman spectroscopy. The release profile of NMD from the systems was assessed by high-performance liquid chromatography. Different spectroscopy methods confirmed the stability of NMD during the sterilization process. The homogeneity of the produced system was proven by Raman spectroscopy and scanning electron microscopy images. In vitro release studies demonstrated the sustained release of NMD over more than 3 months from both NMD systems. In summary, homogeneous nimodipine-starch implants were produced and characterized, which can be used for therapeutic purposes in the brain.
Collapse
Affiliation(s)
- Golbarg Esfahani
- Institute of Pharmacy, Martin Luther University Halle-Wittenberg, Wolfgang-Langenbeck-Straße 4, Halle 06120, Saale, Germany
| | - Marie-Luise Trutschel
- Institute of Pharmacy, Martin Luther University Halle-Wittenberg, Wolfgang-Langenbeck-Straße 4, Halle 06120, Saale, Germany
| | - Detlef Reichert
- Institute of Physics, Martin Luther University Halle-Wittenberg, Betty-Heimann-Str. 7, Halle D-06120, Saale, Germany
| | - Karsten Mäder
- Institute of Pharmacy, Martin Luther University Halle-Wittenberg, Wolfgang-Langenbeck-Straße 4, Halle 06120, Saale, Germany
| |
Collapse
|
2
|
Duchowny A, Ortiz Restrepo SA, Kern S, Adams A. Quantification of PVC plasticizer mixtures by compact proton NMR spectroscopy and indirect hard modeling. Anal Chim Acta 2022; 1229:340384. [PMID: 36156235 DOI: 10.1016/j.aca.2022.340384] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2022] [Revised: 08/19/2022] [Accepted: 09/08/2022] [Indexed: 11/28/2022]
Abstract
A novel approach is introduced for the fast, reliable, and low-cost recognition and quantification of plasticizers in plasticizers mixtures. It uses benchtop 1H NMR spectroscopy and indirect hard modeling, a mechanistic multivariate regression technique. The approach is demonstrated on five different PVC plasticizers having similar spectral signatures in proton NMR spectra. With only 16 scans per spectrum, i.e., 2 min 40 s measurement time, quantification limits down to 0.14 mg mL-1, or 0.35 wt% plasticizer in PVC, were achieved. Apart from the rapid data acquisition, the use of spectral hard modeling enabled the quantification of plasticizer mixtures while using only 4 to 6 training samples per component. Despite strongly overlapping signals in the NMR spectra, various plasticizers were differentiated and quantified, as exemplarily demonstrated for binary mixtures. A commercial PVC specimen with three different layers was also examined, confirming the applicability of benchtop NMR spectroscopy. Additionally, the use of the proposed method to validate official regulations concerning the plasticizer content in PVC is assessed. The presented results demonstrate that the combination of benchtop NMR and spectral hard modeling is a very promising analytical tool for rapid PVC plasticizer recognition and quantification with high analytical throughput. Moreover, the results indicate a high potential for benchtop NMR and spectral hard modeling for microchemical analysis, even for complex samples.
Collapse
Affiliation(s)
- Anton Duchowny
- Institut für Technische und Makromolekulare Chemie, RWTH Aachen University, Templergraben 55, 52056, Aachen, Germany
| | | | - Simon Kern
- S-PACT GmbH, Burtscheider Str. 1, 52064, Aachen, Germany
| | - Alina Adams
- Institut für Technische und Makromolekulare Chemie, RWTH Aachen University, Templergraben 55, 52056, Aachen, Germany.
| |
Collapse
|
3
|
Bellaire D, Thielen S, Burkhart C, Münnemann K, Hasse H, Sauer B. Investigation of Radial Shaft Seal Swelling Using a Special Tribometer and Magnetic Resonance Imaging. ACS OMEGA 2022; 7:11671-11677. [PMID: 35449965 PMCID: PMC9017097 DOI: 10.1021/acsomega.1c06521] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/19/2021] [Accepted: 03/07/2022] [Indexed: 06/14/2023]
Abstract
Compatibility between the rubber material of radial shaft seals and the lubricants to be sealed is an important requirement that customers demand of their lubricant suppliers. Among other effects that may result from incompatibility, the penetration of lubricant components into the rubber (swelling) can impair the seal's functionality due to changes in its geometry and mechanical behavior. Typically, the penetration of a lubricant into an elastomer is evaluated after an immersion test using volumetric, gravimetric, and extraction measurements. Due to the small changes that need to be detected, such methods may not be sufficient to obtain meaningful results. In this contribution, we use magnetic resonance imaging (MRI) to investigate swelling on special tribometer samples as well as a radial shaft seal that were previously used in component tests. Several combinations of rubbers and lubricants that have proven to be compatible were tested in addition to combinations with expected incompatibilities in real applications. The results indicate that MRI measurements can be used to quantify the penetration depth and potentially also the velocity with which the lubricant diffuses into the rubber, thereby yielding detailed insights into the swelling process of the seal.
Collapse
Affiliation(s)
- Daniel Bellaire
- Laboratory
of Engineering Thermodynamics (LTD), TU
Kaiserslautern, Kaiserslautern, Rhineland-Palatinate 67663, Germany
| | - Stefan Thielen
- Institute
of machine elements, gears & transmissions (MEGT), TU Kaiserslautern, Kaiserslautern, Rhineland-Palatinate 67663, Germany
| | - Christoph Burkhart
- Institute
of machine elements, gears & transmissions (MEGT), TU Kaiserslautern, Kaiserslautern, Rhineland-Palatinate 67663, Germany
| | - Kerstin Münnemann
- Laboratory
of Engineering Thermodynamics (LTD), TU
Kaiserslautern, Kaiserslautern, Rhineland-Palatinate 67663, Germany
| | - Hans Hasse
- Laboratory
of Engineering Thermodynamics (LTD), TU
Kaiserslautern, Kaiserslautern, Rhineland-Palatinate 67663, Germany
| | - Bernd Sauer
- Institute
of machine elements, gears & transmissions (MEGT), TU Kaiserslautern, Kaiserslautern, Rhineland-Palatinate 67663, Germany
| |
Collapse
|
4
|
Xia Z, Wang Y, Gong K, Chen W. An in situ stretching instrument combined with low field nuclear magnetic resonance (NMR): Rheo-Spin NMR. THE REVIEW OF SCIENTIFIC INSTRUMENTS 2022; 93:033905. [PMID: 35364982 DOI: 10.1063/5.0080767] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/03/2021] [Accepted: 02/20/2022] [Indexed: 06/14/2023]
Abstract
An in situ stretching instrument combined with low field nuclear magnetic resonance (LF-NMR) was designed and developed, namely, Rheo-Spin NMR. The time resolved stress-strain curve together with the corresponding NMR signal can be simultaneously obtained. The Rheo-Spin NMR contains the functional modules, including (1) the in situ stretching module, (2) the NMR signal acquisition module, and (3) the cavity of the NMR positioning module. The unique ring-like shape of the sample is used to replace the traditional dumbbell sample due to limited space in the NMR probe, and the whole ring-like sample will be deformed during the uniaxial stretching process, which avoids the generation of interference signals from the undeformed sample. The designed stretching assembly made by zirconia ceramics is manufactured to match and stretch the ring-like samples. The strain rate can be tuned within the range of 10-5-10-2 s-1 with the maximum stretching ratio λmax of ∼3.8. The in situ stretching experiments combined with LF-NMR were carried out successfully with natural rubber of different fractions of carbon black. The time-resolved T2 relaxometry was adopted to evaluate segmental relaxation during uniaxial deformation which, for the first time, provides the direct and in situ molecular dynamics information. The Rheo-Spin NMR is promising to provide more in-depth insights into the structure and dynamics evolution of polymer products under real service conditions.
Collapse
Affiliation(s)
- Zhijie Xia
- National Synchrotron Radiation Laboratory, Anhui Provincial Engineering Laboratory of Advanced Functional Polymer Film, CAS Key Laboratory of Soft Matter Chemistry, University of Science and Technology of China, Hefei 230026, China
| | - Yusong Wang
- Hefei National Laboratory for Physical Sciences at the Microscale, University of Science and Technology of China, Hefei 230026, China
| | - Ke Gong
- Hefei National Laboratory for Physical Sciences at the Microscale, University of Science and Technology of China, Hefei 230026, China
| | - Wei Chen
- National Synchrotron Radiation Laboratory, Anhui Provincial Engineering Laboratory of Advanced Functional Polymer Film, CAS Key Laboratory of Soft Matter Chemistry, University of Science and Technology of China, Hefei 230026, China
| |
Collapse
|
5
|
Nicasy R, Huinink H, Erich B, Olaf A. NMR Profiling of Reaction and Transport in Thin Layers: A Review. Polymers (Basel) 2022; 14:798. [PMID: 35215714 PMCID: PMC8963059 DOI: 10.3390/polym14040798] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2021] [Revised: 01/25/2022] [Accepted: 02/14/2022] [Indexed: 02/04/2023] Open
Abstract
Reaction and transport processes in thin layers of between 10 and 1000 µm are important factors in determining their performance, stability and degradation. In this review, we discuss the potential of high-gradient Nuclear Magnetic Resonance (NMR) as a tool to study both reactions and transport in these layers spatially and temporally resolved. As the NMR resolution depends on gradient strength, the high spatial resolution required in submillimeter layers can only be achieved with specially designed high-gradient setups. Three different high-gradient setups exist: STRAFI (STRay FIeld), GARField (Gradient-At-Right-angles-to-Field) and MOUSE (MObile Universal Surface Explorer). The aim of this review is to provide a detailed overview of the three techniques and their ability to visualize reactions and transport processes using physical observable properties such as hydrogen density, diffusion, T1- and T2-relaxation. Finally, different examples from literature will be presented to illustrate the wide variety of applications that can be studied and the corresponding value of the techniques.
Collapse
Affiliation(s)
- Ruben Nicasy
- Applied Physics Department, Eindhoven University of Technology, P.O. Box 513, 5600 MB Eindhoven, The Netherlands; (R.N.); (B.E.); (A.O.)
| | - Henk Huinink
- Applied Physics Department, Eindhoven University of Technology, P.O. Box 513, 5600 MB Eindhoven, The Netherlands; (R.N.); (B.E.); (A.O.)
| | - Bart Erich
- Applied Physics Department, Eindhoven University of Technology, P.O. Box 513, 5600 MB Eindhoven, The Netherlands; (R.N.); (B.E.); (A.O.)
- Organization of Applied Scientific Research, TNO The Netherlands, P.O. Box 49, 2600 AA Delft, The Netherlands
| | - Adan Olaf
- Applied Physics Department, Eindhoven University of Technology, P.O. Box 513, 5600 MB Eindhoven, The Netherlands; (R.N.); (B.E.); (A.O.)
- Organization of Applied Scientific Research, TNO The Netherlands, P.O. Box 49, 2600 AA Delft, The Netherlands
| |
Collapse
|
6
|
Screening Metal-Organic Frameworks for Separation of Binary Solvent Mixtures by Compact NMR Relaxometry. Molecules 2021; 26:molecules26123481. [PMID: 34201035 PMCID: PMC8228364 DOI: 10.3390/molecules26123481] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2021] [Revised: 06/04/2021] [Accepted: 06/05/2021] [Indexed: 01/18/2023] Open
Abstract
Metal–organic frameworks (MOFs) have great potential as an efficient alternative to current separation and purification procedures of a large variety of solvent mixtures—a critical process in many applications. Due to the huge number of existing MOFs, it is of key importance to identify high-throughput analytical tools, which can be used for their screening and performance ranking. In this context, the present work introduces a simple, fast, and inexpensive approach by compact low-field proton nuclear magnetic resonance (NMR) relaxometry to investigate the efficiency of MOF materials for the separation of a binary solvent mixture. The mass proportions of two solvents within a particular solvent mixture can be quantified before and after separation with the help of a priori established correlation curves relating the effective transverse relaxation times T2eff and the mass proportions of the two solvents. The new method is applied to test the separation efficiency of powdered UiO-66(Zr) for various solvent mixtures, including linear and cyclic alkanes and benzene derivate, under static conditions at room temperature. Its reliability is demonstrated by comparison with results from 1H liquid-state NMR spectroscopy.
Collapse
|
7
|
Compact NMR Spectroscopy for Low-Cost Identification and Quantification of PVC Plasticizers. Molecules 2021; 26:molecules26051221. [PMID: 33668752 PMCID: PMC7956471 DOI: 10.3390/molecules26051221] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2021] [Revised: 02/21/2021] [Accepted: 02/22/2021] [Indexed: 11/17/2022] Open
Abstract
Polyvinyl chloride (PVC), one of the most important polymer materials nowadays, has a large variety of formulations through the addition of various plasticizers to meet the property requirements of the different fields of applications. Routine analytical methods able to identify plasticizers and quantify their amount inside a PVC product with a high analysis throughput would promote an improved understanding of their impact on the macroscopic properties and the possible health and environmental risks associated with plasticizer leaching. In this context, a new approach to identify and quantify plasticizers employed in PVC commodities using low-field NMR spectroscopy and an appropriate non-deuterated solvent is introduced. The proposed method allows a low-cost, fast, and simple identification of the different plasticizers, even in the presence of a strong solvent signal. Plasticizer concentrations below 2 mg mL-1 in solution corresponding to 3 wt% in a PVC product can be quantified in just 1 min. The reliability of the proposed method is tested by comparison with results obtained under the same experimental conditions but using deuterated solvents. Additionally, the type and content of plasticizer in plasticized PVC samples were determined following an extraction procedure. Furthermore, possible ways to further decrease the quantification limit are discussed.
Collapse
|
8
|
Aiello F, Gerretzen J, Simons MG, Davies AN, Dani P. A multivariate approach to investigate the NMR CPMG pulse sequence for analysing low MW species in polymers. MAGNETIC RESONANCE IN CHEMISTRY : MRC 2021; 59:172-186. [PMID: 32929750 DOI: 10.1002/mrc.5100] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/03/2020] [Revised: 09/10/2020] [Accepted: 09/10/2020] [Indexed: 06/11/2023]
Abstract
Detection and quantification of low molecular weight components in polymeric samples via nuclear magnetic resonance (NMR) spectroscopy can be difficult due to overlapping signal caused by line broadening characteristics of polymers. A way of overcoming this problem could be the exploitation of the difference in relaxation between small molecules and macromolecular species, such as the application of a T2 filter by using the Carr-Purcell-Meiboom-Gill (CPMG) spin-echo pulse sequence. This technique, largely exploited in metabolomics studies, is applied here to material sciences. A Design of Experiments approach was used for evaluating the effect of different acquisition parameters (relaxation delay, echo time and number of cycles) and sample-related ones (concentration and polymer molecular weight) on selected responses, with a particular interest in performing a reliable quantitative analysis. Polymeric samples containing small molecules were analysed by NMR with and without the application of the filter, and analysis of variance was used to identify the most influential parameters. Results indicated that increasing the polymer concentration, hence sample viscosity, further attenuates polymer signals in CPMG experiments because the T2 of those signals tends to decrease with increasing viscosity. The signal-to-noise ratio measured for small molecules can undergo a minimum loss when specific parameters are chosen in relation to the polymer molecular weight. Furthermore, the difference in dynamics between aliphatic and aromatic nuclei, as well as between mobile and stiff polymers, translates into different results in terms of polymer signal reduction, suggesting that the relaxation filter can also be used for obtaining information on the polymer structure.
Collapse
Affiliation(s)
- Federica Aiello
- ECG-MAS, Expert Capability Group - Measurement and Analytical Science, Nouryon Chemicals B.V., Deventer, The Netherlands
| | - Jan Gerretzen
- ECG-MAS, Expert Capability Group - Measurement and Analytical Science, Nouryon Chemicals B.V., Deventer, The Netherlands
| | - Marcel G Simons
- ECG-MAS, Expert Capability Group - Measurement and Analytical Science, Nouryon Chemicals B.V., Deventer, The Netherlands
| | - Antony N Davies
- ECG-MAS, Expert Capability Group - Measurement and Analytical Science, Nouryon Chemicals B.V., Deventer, The Netherlands
- SERC, Sustainable Environment Research Centre, Faculty of Computing Engineering and Science, University of South Wales, Pontypridd, UK
| | - Paulo Dani
- ECG-MAS, Expert Capability Group - Measurement and Analytical Science, Nouryon Chemicals B.V., Deventer, The Netherlands
| |
Collapse
|
9
|
Rudszuck T, Nirschl H, Guthausen G. Perspectives in process analytics using low field NMR. JOURNAL OF MAGNETIC RESONANCE (SAN DIEGO, CALIF. : 1997) 2021; 323:106897. [PMID: 33518174 DOI: 10.1016/j.jmr.2020.106897] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/29/2020] [Revised: 12/15/2020] [Accepted: 12/18/2020] [Indexed: 06/12/2023]
Abstract
Low field NMR is a powerful analytical tool which creates an enormous added value in process analytics. Based on specific applications in process analytics and perspectives for low field NMR in form of spectroscopy, relaxation, diffusion, and imaging in quality control, diverse applications and technical realizations like spectrometers, time domain NMR, mobile NMR sensors and MRI will be discussed.
Collapse
Affiliation(s)
- T Rudszuck
- Institute for Mechanical Engineering and Mechanics, KIT, 76131 Karlsruhe, Germany
| | - H Nirschl
- Institute for Mechanical Engineering and Mechanics, KIT, 76131 Karlsruhe, Germany
| | - G Guthausen
- Institute for Mechanical Engineering and Mechanics, KIT, 76131 Karlsruhe, Germany; Engler-Bunte Institut, Water Science and Technology, KIT, 76131 Karlsruhe, Germany
| |
Collapse
|
10
|
Kelley M, Abdol N, Soroushian P, Keating K, Balachandra AM, Meldrum T. Monitoring real‐time curing of epoxies in situ using single‐sided NMR. JOURNAL OF POLYMER SCIENCE 2020. [DOI: 10.1002/pol.20190117] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
| | | | | | - Kristina Keating
- Department of Earth and Environmental SciencesRutgers University Newark New Jersey
| | | | - Tyler Meldrum
- Department of ChemistryWilliam & Mary Williamsburg Virginia
| |
Collapse
|
11
|
Garcia RHS, Filgueiras JG, deAzevedo ER, Colnago LA. Power-optimized, time-reversal pulse sequence for a robust recovery of signals from rigid segments using time domain NMR. SOLID STATE NUCLEAR MAGNETIC RESONANCE 2019; 104:101619. [PMID: 31470338 DOI: 10.1016/j.ssnmr.2019.101619] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/14/2019] [Revised: 08/09/2019] [Accepted: 08/12/2019] [Indexed: 06/10/2023]
Abstract
Time domain NMR (TD-NMR) has been widely used on the analysis of liquids or liquid components in heterogeneous materials such as food, biological tissues, synthetic and bio polymers, oil-bearing rocks, biomasses and cement-based materials. The use of TD-NMR for studying solid and soft mater has been growing in number and variety of applications, mostly for organic systems where the detection of 1H signals is highly advantageous. However, the strong 1H-1H dipolar interactions in solids make the 1H FID to decay in the same order of the dead time of most commercially available NMR probe heads. Thus, solid echoes are often used for recovering signals from solid components. In this article we reinvestigate the time-reversal solid-echo pulse sequence proposed by Rhim and Kessemeier, seeking for optimal pulse power and timing conditions that maximize its efficiency on recovering 1H signals from rigid segments. We show that under these optimized conditions, which we denote as Rhim and Kessemeier - Radiofrequency Optimized Solid-Echo (RK-ROSE), the experiment can be more efficient than its most popular counterparts Solid-Echo (SE) and mixed-Magic Sandwich Echoes (mixed-MSE). Our results also suggest that, despite the finite pulse power, with current probe technology the RK-ROSE experiment is potentially able to provide an accurate estimation of rigid components, without relying on an external calibration using multiple standard samples, as usually done in SFC analysis of the FID signal. At last, we demonstrate that RK-ROSE can be adapted as a simple filter to supress signals from mobile segments in heterogeneous materials.
Collapse
Affiliation(s)
- Rodrigo H S Garcia
- Instituto de Química de São Carlos, Universidade de São Paulo, CP 369, 13660-970, São Carlos, SP, Brazil
| | - Jefferson G Filgueiras
- Instituto de Física de São Carlos, Universidade de São Paulo, CP 369, 13660-970, São Carlos, SP, Brazil
| | - Eduardo R deAzevedo
- Instituto de Física de São Carlos, Universidade de São Paulo, CP 369, 13660-970, São Carlos, SP, Brazil.
| | - Luiz Alberto Colnago
- Embrapa Instrumentação, Rua XV de Novembro, 1452, 13560-970, Brazil, São Carlos, SP, Brazil.
| |
Collapse
|
12
|
Drzeżdżon J, Jacewicz D, Sielicka A, Chmurzyński L. A review of new approaches to analytical methods to determine the structure and morphology of polymers. Trends Analyt Chem 2019. [DOI: 10.1016/j.trac.2019.06.013] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
|
13
|
Cold-adaptation of a methacrylamide gelatin towards the expansion of the biomaterial toolbox for specialized functionalities in tissue engineering. MATERIALS SCIENCE & ENGINEERING. C, MATERIALS FOR BIOLOGICAL APPLICATIONS 2019; 102:373-390. [DOI: 10.1016/j.msec.2019.04.020] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/11/2018] [Revised: 03/28/2019] [Accepted: 04/08/2019] [Indexed: 02/06/2023]
|
14
|
Time Domain NMR in Polymer Science: From the Laboratory to the Industry. APPLIED SCIENCES-BASEL 2019. [DOI: 10.3390/app9091801] [Citation(s) in RCA: 44] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Highly controlled polymers and nanostructures are increasingly translated from the lab to the industry. Together with the industrialization of complex systems from renewable sources, a paradigm change in the processing of plastics and rubbers is underway, requiring a new generation of analytical tools. Here, we present the recent developments in time domain NMR (TD-NMR), starting with an introduction of the methods. Several examples illustrate the new take on traditional issues like the measurement of crosslink density in vulcanized rubber or the monitoring of crystallization kinetics, as well as the unique information that can be extracted from multiphase, nanophase and composite materials. Generally, TD-NMR is capable of determining structural parameters that are in agreement with other techniques and with the final macroscopic properties of industrial interest, as well as reveal details on the local homogeneity that are difficult to obtain otherwise. Considering its moderate technical and space requirements of performing, TD-NMR is a good candidate for assisting product and process development in several applications throughout the rubber, plastics, composites and adhesives industry.
Collapse
|
15
|
Chakrapani SB, Minkler MJ, Beckingham BS. Low-field 1H-NMR spectroscopy for compositional analysis of multicomponent polymer systems. Analyst 2019; 144:1679-1686. [PMID: 30656299 DOI: 10.1039/c8an01810c] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
The accurate characterization of relative composition in multicomponent polymer systems such as statistical copolymers, block copolymers, and polymer blends is critical to understanding and predicting their behavior. Typically, polymer compositional analysis is performed using 1H Nuclear Magnetic Resonance (NMR) Spectroscopy which provides quantitative chemical group concentrations without prior calibration. This utility has led 1H NMR spectroscopy to become a routine method for the molecular characterization of polymers. Unfortunately, due to cost constraints, NMR spectroscopy is rarely used for routine materials verification such as quality control in industrial settings that commonly lack on-site advanced instrumentation facilities. Recently, low-field or so-called benchtop NMR spectrometers have been introduced commercially as a less expensive alternative to higher field, and costlier, NMR spectrometers. Here, we examine the capability of a low-field 1H NMR spectrometer (60 MHz) for the compositional analysis of select block copolymers and polymer blends by direct comparison with results obtained using a 400 MHz NMR spectrometer. In the analysis of high 1,4-content polyisoprene we find quantitative agreement between the 400 and 60 MHz spectrometers. Furthermore, quantitative agreement is demonstrated for compositional analysis of commercially available poly(styrene-b-isoprene-b-styrene) (SIS) and poly(styrene-b-butadiene-b-styrene) (SBS) triblock copolymers and polymer blends of polystyrene/polyisoprene (PS/PI) and polystyrene/poly(methyl methacrylate) (PS/PMMA) that also serve as proxies for statistical and block copolymer analysis. Overall, we find low-field 1H NMR spectroscopy to be an accessible, powerful and useful tool for polymer characterization.
Collapse
Affiliation(s)
- Sneha B Chakrapani
- Dept. of Chemical Engineering, Auburn University, Auburn, AL 36849, USA.
| | | | | |
Collapse
|
16
|
Räntzsch V, Haas M, Özen MB, Ratzsch KF, Riazi K, Kauffmann-Weiss S, Palacios JK, Müller AJ, Vittorias I, Gisela Guthausen, Wilhelm M. Polymer crystallinity and crystallization kinetics via benchtop 1H NMR relaxometry: Revisited method, data analysis, and experiments on common polymers. POLYMER 2018. [DOI: 10.1016/j.polymer.2018.04.066] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
|
17
|
Sommer S, Koch M, Adams A. Terahertz Time-Domain Spectroscopy of Plasticized Poly(vinyl chloride). Anal Chem 2018; 90:2409-2413. [PMID: 29397690 DOI: 10.1021/acs.analchem.7b04548] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Poly(vinyl chloride) (PVC) is today one of the most important commodity polymers. Its broad range of applications is due to the presence of plasticizers whose concentration largely impacts the microscopic and the macroscopic properties. Quantifying the concentration of plasticizer in PVC products is therefore of fundamental importance. Thus, in this paper, the applicability of terahertz (THz) time-domain spectroscopy for the characterization of plasticized PVC is for the first time evaluated in a systematic way. It could be demonstrated that the method is able to distinguish between PVC samples with different types and concentrations of plasticizers. Furthermore, a simple, fast, and efficient method is introduced to quantify the concentration of plasticizer in PVC samples of known plasticizer type but different thermal histories. The presented results are of key importance due to the need of reliable noninvasive and nondestructive analytical methods which can deliver onsite information about the remaining plasticizer concentration inside PVC products. Furthermore, it is expected that the proposed approach can be easily extended to other plasticized polymers.
Collapse
Affiliation(s)
- Stefan Sommer
- Faculty of Physics and Material Sciences Center, Philipps-Universität Marburg , Renthof 5, 35032 Marburg, Germany
| | - Martin Koch
- Faculty of Physics and Material Sciences Center, Philipps-Universität Marburg , Renthof 5, 35032 Marburg, Germany
| | - Alina Adams
- Institut für Technische und Makromolekulare Chemie, RWTH Aachen University , Templergraben 55, D-52056 Aachen, Germany
| |
Collapse
|
18
|
Blümich B, Singh K. Desktop NMR and Its Applications From Materials Science To Organic Chemistry. Angew Chem Int Ed Engl 2017; 57:6996-7010. [PMID: 29230908 DOI: 10.1002/anie.201707084] [Citation(s) in RCA: 56] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2017] [Indexed: 12/19/2022]
Abstract
NMR spectroscopy is an indispensable method of analysis in chemistry, which until recently suffered from high demands for space, high costs for acquisition and maintenance, and operational complexity. This has changed with the introduction of compact NMR spectrometers suitable for small-molecule analysis on the chemical workbench. These spectrometers contain permanent magnets giving rise to proton NMR frequencies between 40 and 80 MHz. The enabling technology is to make small permanent magnets with homogeneous fields. Tabletop instruments with inhomogeneous fields have been in use for over 40 years for characterizing food and hydrogen-containing materials by relaxation and diffusion measurements. Related NMR instruments measure these parameters in the stray field outside the magnet. They are used to inspect the borehole walls of oil wells and to test objects nondestructively. The state-of-the-art of NMR spectroscopy, imaging and relaxometry with compact instruments is reviewed.
Collapse
Affiliation(s)
- Bernhard Blümich
- Institut für Technische und Makromolekulare Chemie, RWTH Aachen University, Aachen, Germany
| | - Kawarpal Singh
- Institut für Technische und Makromolekulare Chemie, RWTH Aachen University, Aachen, Germany
| |
Collapse
|
19
|
Blümich B, Singh K. NMR mit Tischgeräten und deren Anwendungen von der Materialwissenschaft bis zur organischen Chemie. Angew Chem Int Ed Engl 2017. [DOI: 10.1002/ange.201707084] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Affiliation(s)
- Bernhard Blümich
- Institut für Technische und Makromolekulare Chemie; RWTH Aachen University; Aachen Deutschland
| | - Kawarpal Singh
- Institut für Technische und Makromolekulare Chemie; RWTH Aachen University; Aachen Deutschland
| |
Collapse
|
20
|
Berger K, Keimel C, Helfer E, Haar B, Mattausch H, Riess G, Kern W. The effects of e-beam crosslinking of LDPE on the permeation of hydrocarbons. J Appl Polym Sci 2017. [DOI: 10.1002/app.44968] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Affiliation(s)
- Katrin Berger
- Polymer Competence Center Leoben GmbH; Roseggerstraße 12 Leoben 8700 Austria
| | - Christian Keimel
- Polymer Competence Center Leoben GmbH; Roseggerstraße 12 Leoben 8700 Austria
| | - Eric Helfer
- Chair in Chemistry of Polymeric Materials; Montanuniversitaet Leoben; Otto-Glöckel-Straße 2 Leoben 8700 Austria
| | - Bernd Haar
- Polymer Competence Center Leoben GmbH; Roseggerstraße 12 Leoben 8700 Austria
| | - Hannelore Mattausch
- Chair in Polymer Processing; Montanuniversitaet Leoben; Otto-Glöckel-Straße 2 Leoben 8700 Austria
| | - Gisbert Riess
- Chair in Chemistry of Polymeric Materials; Montanuniversitaet Leoben; Otto-Glöckel-Straße 2 Leoben 8700 Austria
| | - Wolfgang Kern
- Polymer Competence Center Leoben GmbH; Roseggerstraße 12 Leoben 8700 Austria
- Chair in Chemistry of Polymeric Materials; Montanuniversitaet Leoben; Otto-Glöckel-Straße 2 Leoben 8700 Austria
| |
Collapse
|
21
|
Singh K, Blümich B. Desktop NMR for structure elucidation and identification of strychnine adulteration. Analyst 2017; 142:1459-1470. [DOI: 10.1039/c7an00020k] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
A complete assignment of the structure of strychnine with NMR spectroscopy at 1 T and identification of strychnine adulteration.
Collapse
Affiliation(s)
- Kawarpal Singh
- Institute for Technical Chemistry and Macromolecular Chemistry
- RWTH Aachen University
- Aachen
- Germany
| | - Bernhard Blümich
- Institute for Technical Chemistry and Macromolecular Chemistry
- RWTH Aachen University
- Aachen
- Germany
| |
Collapse
|
22
|
|