Nanostructured Thermoplastic Elastomers Based on SBS Triblock Copolymer Stiffening with Low Contents of Epoxy System. Morphological Behavior and Mechanical Properties

Ocando, Connie; Fernández, Raquel; Tercjak, Agnieszka; Mondragón, Iñaki; Eceiza, Arantxa

doi:10.1021/ma400152g

Cited by 43 publications

(20 citation statements)

References 55 publications

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“…SBS triblock copolymers with 60-80% mobile fraction are among the widely used thermoplastic elastomers due to their excellent mechanical performance, such as high tensile strength and elongation at break [59]. As the mobile phase plays an important role in controlling and modulating the mechanical performance of SBS, comprehensive characterization of these mobile components is significant for further understanding their influence on the mechanical properties of SBS copolymers [60].…”

Section: Resultsmentioning

confidence: 99%

Hybridizing cross-polarization with NOE or refocused-INEPT enhances the sensitivity of MAS NMR spectroscopy

Zhang

Mroué

Ramamoorthy

2016

Journal of Magnetic Resonance

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Heteronuclear cross polarization (CP) has been commonly used to enhance the sensitivity of dilute low-γ nuclei in almost all solid-state NMR experiments. However, CP relies on heteronuclear dipolar couplings, and therefore the magnetization transfer efficiency becomes inefficient when the dipolar couplings are weak, as is often the case for mobile components in solids. Here, we demonstrate methods that combine CP with heteronuclear Overhauser effect (referred to as CP-NOE) or with refocused-INEPT (referred to as CP-RINEPT) to overcome the efficiency limitation of CP and enhance the signal-to-noise ratio (S/N) for mobile components. Our experimental results reveal that, compared to the conventional CP, significant S/N ratio enhancement can be achieved for resonances originating from mobile components, whereas the resonance signals associated with rigid groups are not significantly affected due to their long spin-lattice relaxation times. In fact, the S/N enhancement factor is also dependent on the temperature, CP contact time as well as on the system under investigation. Furthermore, we also demonstrate that CP-RINEPT experiment can be successfully employed to independently detect mobile and rigid signals in a single experiment without affecting the data collection time. However, the resolution of CP spectrum obtained from the CP-RINEPT experiment could be slightly compromised by the mandatory use of continuous wave (CW) decoupling during the acquisition of signals from rigid components. In addition, CP-RINEPT experiment can be used for spectral editing utilizing the difference in dynamics of different regions of a molecule and/or different components present in the sample, and could also be useful for the assignment of resonances from mobile components in poorly resolved spectra. Therefore, we believe that the proposed approaches are beneficial for the structural characterization of multiphase and heterogeneous systems, and could be used as a building block in multidimensional solid-state NMR experiments.

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Section: Resultsmentioning

confidence: 99%

Hybridizing cross-polarization with NOE or refocused-INEPT enhances the sensitivity of MAS NMR spectroscopy

Zhang

Mroué

Ramamoorthy

2016

Journal of Magnetic Resonance

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“…and processability, SBS triblock copolymers with 60% ∼ 80% mobile fraction are one of the main commercial and widely used thermoplastic elastomer. 58 Because of the significance of mobile phase in controlling and modulating the mechanical performance of SBS, a selective observation of signals from mobile regions is necessary for further understanding its effect on the properties of SBS. The experimental results obtained from SBS are shown in Figs.…”

Section: Resultsmentioning

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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“…ABA‐type block copolymers as thermoplastic elastomers have been widely studied for improving the mechanical properties of brittle polymers due to their unique morphological characteristics . Styrene‐based block copolymers are examples of some of the most widely used ABA‐type block copolymers where the brittle property of styrene can be improved by the addition of rubbery butadiene or isoprene as the middle block.…”

Section: Introductionmentioning

confidence: 99%

“…ABA-type block copolymers as thermoplastic elastomers have been widely studied for improving the mechanical properties of brittle polymers due to their unique morphological characteristics. [33][34][35] Styrene-based block copolymers are examples of some of the most widely used ABA-type block copolymers where the brittle property of styrene can be improved by the addition of rubbery butadiene or isoprene as the middle block. In styrene-based ABA-type block copolymers, the immiscibility of the different blocks leads to microphase separation with the hard domains physically connected by the rubbery blocks to give a superior resistance to creep.…”

Section: Introductionmentioning

confidence: 99%

Influence of aliphatic polycarbonate middle block on mechanical and microstructural behaviour of triblock copolymers based on poly(l‐lactide) and polycarbonate

Konwar

Satapathy

Jacob

2018

Polymer International

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Three different ABA‐type triblock copolymers each containing biodegradable aliphatic polycarbonate as the middle block and poly(l‐lactide) as the outer blocks were synthesized and the influence of the methylene chain length of the aliphatic polycarbonate middle block on various properties of the triblock copolymers was evaluated. Differential scanning calorimetry and wide‐angle X‐ray diffraction studies revealed that the incorporation of the outer blocks reduced the crystallinity of the middle aliphatic polycarbonate block. Variation of methylene chain length of the middle block led to a change in morphology from spherical to cylindrical as evidenced from atomic force microscopy studies. In addition, the mechanical properties of the block copolymers showed semi‐ductile to quasi‐brittle behaviour depending upon the composition of the middle block which was also confirmed using scanning electron microscopy. Dynamic mechanical analysis of the triblock copolymers indicated that storage modulus increased with a decrease in methylene chain length. © 2018 Society of Chemical Industry

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Nanostructured Thermoplastic Elastomers Based on SBS Triblock Copolymer Stiffening with Low Contents of Epoxy System. Morphological Behavior and Mechanical Properties

Cited by 43 publications

References 55 publications

Hybridizing cross-polarization with NOE or refocused-INEPT enhances the sensitivity of MAS NMR spectroscopy

Hybridizing cross-polarization with NOE or refocused-INEPT enhances the sensitivity of MAS NMR spectroscopy

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

Influence of aliphatic polycarbonate middle block on mechanical and microstructural behaviour of triblock copolymers based on poly(l‐lactide) and polycarbonate

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