Solid state NMR investigation of cationic polymerized epoxy resins

Egger, Norbert; Schmidt‐Rohr, Klaus; Blümich, Bernhard; Domke, Wolf-Dieter; Stapp, Bernhard

doi:10.1002/app.1992.070440213

Cited by 128 publications

(153 citation statements)

References 26 publications

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“…The measurements of 1 H spin diffusion and 1 H T 1 relaxation times were collected via cross-polarization to 13 C on a Bruker ASX-200 spectrometer operating at 50.3 MHz. In the spin diffusion measurement, magnetization in the PS core was suppressed using a dipolar filter pulse sequence 19 and the recovery of NMR signals in PS was monitored. The spin diffusion data were obtained by a simple phase cycle of pulses before the mixing time in which the magnetization in PS was stored alternately between ϩz and Ϫz.…”

Section: Methodsmentioning

confidence: 99%

Spin diffusion and spin-lattice relaxation in multiphase polymers

Wang

Jack

Natansohn

1997

The Journal of Chemical Physics

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Reuse of AIP Publishing content is subject to the terms: https://publishing.aip.org/authors/rights-and-permissions. A model which treats spin diffusion and spin-lattice relaxation in multiphase polymers on the same footing is proposed. This new approach allows for more accurate determination of domain sizes and interfacial thickness in the probed polymers. In a poly͑styrene-b-isoprene͒ copolymer example a significant improvement in the agreement between the NMR measurements and the simulated results can be obtained with the incorporation of a spin-lattice relaxation term into the spin diffusion process. The obtained microphase structural parameters are similar to the small angle X-ray scattering results. In addition, the spin-lattice relaxation times ͑T 1 ) in different domains can be predicted reasonably well based on T 1 s of the component homopolymers and on the microphase structure in the present model.

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Section: Methodsmentioning

confidence: 99%

Spin diffusion and spin-lattice relaxation in multiphase polymers

Wang

Jack

Natansohn

1997

The Journal of Chemical Physics

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“…Since then, various similar techniques have been proposed (2)(3)(4)(5)(6)(7). One of those is the "dipolar filter" proposed by Spiess and co-workers (8) and subsequently applied to some soft-hard polymer pairs (9)(10)(11)(12). Thermoplastic elastomers are such phase-separated polymer systems consisting of a dominant rubbery phase and a dispersed rigid phase.…”

Section: Introductionmentioning

confidence: 99%

Spin diffusion in a triblock thermoplastic elastomer

Cho¹,

Natansohn²

1994

Can. J. Chem.

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GYUNGGOO CHO and ALMERIA NATANSOHN. Can. J. Chem. 72,2255Chem. 72, (1994. A triblock copolymer thermoplastic elastomer (SEBS) consisting of an ethylene-butylene random-copolymer rubbery domain flanked by rigid polystyrene short blocks has been analyzed using novel solid-state NMR techniques. I3C NMR relaxation measurements suggest that at the T,(H) level (minimum observable phase size of about 18 nm) the material appears homogeneous, but at the T,,(H) level (minimum observable phase size of about 3 nm) the expected two distinct phases are noted. Two-dimensional WISE spectra (high-resolution I3c -broadline 'H) show the different ~liobility in the two phases. A broad component associated with the highly mobile rubbery phase indicates the presence of an interface. The mobile phase is selected using a dipolar filter pulse sequence and the magnetization is allowed to transfer to the rigid polystyrene phase during a period called "mixing time." From the growth of the polystyrene magnetization during the mixing period, the size of the dispersed polystyrene phase can be calculated to be 16 Z 2 nm.GYUNGGOO CHO et ALMERIA NATANSOHN. Can. J. Chem. 72,2255(1994.Faisant appel aux nouvelles techniques de la RMN de l'ttat solide, on a analyst un Clastomkre thermoplastique, un copolymbre h trois blocs (SEBS) form6 du domaine caoutchoutC d'un copolymbre alCatoire d'tthylbne-butylkne flanqut de petits blocs de polystyrkne rigide. Les mesures de relaxation de la RMN du I3C suggkrent que, au niveau T,(H) (taille minimale de la phase observable d'environ 18 nm), le produit semble homogbne, mais que au niveau Tl,(H) (taille minimale de la phase observable d'environ 3 nm), on peut noter les deux phases distinctes attendues. Le spectre WISE bidimensionel (13c A haute rCsolution et 'H avec des raies larges) montre la mobilitC differente dans les deux phases. Une composante importante associte h la phase caoutchoutt trbs mobile indique la prCsence d'une interface. On choisit la phase mobile en utilisant un filtre dipolaire h sequence pulsCe et on permet h la magnetisation de se transftrer A la phase polystyrbne rigide au cours d'une pCriode que l'on appelle cctemps de mClangen. En se basant sur la croissance de la magnetisation du polystyrbne durant le ptriode de melange, on a calculC que la taille de la phase polystyrbne dispersCe est de 16 2 nm.[Traduit par la rCdaction]

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“…• RF pulses [43][44][45] is used to select the 1 H magnetization from a mobile component, which has a long transverse relaxation time than the rigid components of the system under investigation. In principle, the proton transverse relaxation time in solid systems is mainly determined by the 1 H-1 H dipolar couplings, which means that the proton signals experiencing strong dipolar couplings will be filtered out first.…”

Section: Pulse Sequencementioning

confidence: 99%

Dynamics-based selective 2D 1H/1H chemical shift correlation spectroscopy under ultrafast MAS conditions

Zhang

Ramamoorthy

2015

The Journal of Chemical Physics

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Dynamics plays important roles in determining the physical, chemical, and functional properties of a variety of chemical and biological materials. However, a material (such as a polymer) generally has mobile and rigid regions in order to have high strength and toughness at the same time. Therefore, it is difficult to measure the role of mobile phase without being affected by the rigid components. Herein, we propose a highly sensitive solid-state NMR approach that utilizes a dipolar-coupling based filter (composed of 12 equally spaced 90• RF pulses) to selectively measure the correlation of 1 H chemical shifts from the mobile regions of a material. It is interesting to find that the rotor-synchronized dipolar filter strength decreases with increasing inter-pulse delay between the 90• pulses, whereas the dipolar filter strength increases with increasing inter-pulse delay under static conditions. In this study, we also demonstrate the unique advantages of proton-detection under ultrafast magic-angle-spinning conditions to enhance the spectral resolution and sensitivity for studies on small molecules as well as multi-phase polymers. Our results further demonstrate the use of finite-pulse radio-frequency driven recoupling pulse sequence to efficiently recouple weak proton-proton dipolar couplings in the dynamic regions of a molecule and to facilitate the fast acquisition of 1 H/ 1 H correlation spectrum compared to the traditional 2D NOESY (Nuclear Overhauser effect spectroscopy) experiment. We believe that the proposed approach is beneficial to study mobile components in multi-phase systems, such as block copolymers, polymer blends, nanocomposites, heterogeneous amyloid mixture of oligomers and fibers, and other materials. C 2015 AIP Publishing LLC. [http://dx

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Solid state NMR investigation of cationic polymerized epoxy resins

Cited by 128 publications

References 26 publications

Spin diffusion and spin-lattice relaxation in multiphase polymers

Spin diffusion and spin-lattice relaxation in multiphase polymers

Spin diffusion in a triblock thermoplastic elastomer

Dynamics-based selective 2D 1H/1H chemical shift correlation spectroscopy under ultrafast MAS conditions

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