Applying Polymer Blend Dynamics Concepts to a Simplified Industrial System. A Combined Effort by Dielectric Spectroscopy and Neutron Scattering

Gambino, Thomas; Alegría, Ángel; Arbe, Arantxa; Colmenero, Juan; Malicki, Nicolas; Dronet, Séverin; Schnell, B.; Lohstroh, Wiebke; Nemkovski, K. S.

doi:10.1021/acs.macromol.8b00881

Cited by 11 publications

(21 citation statements)

References 41 publications

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“…It is worth noting that the PS block of the PSPI 2 copolymers has been isotopically substituted (deuterium for hydrogen) for possible future neutron scattering and 1 H NMR studies. Differences between deuterated and nondeuterated PS have been shown to be negligible in self-assembled phase separation and in the dielectric response of the PI chains measured by BDS at temperatures below the dynamic glass-transition temperature of deuterated PS ( T g ∼ 105 °C). , …”

Section: Methodsmentioning

confidence: 99%

Effects of Asymmetric Molecular Architecture on Chain Stretching and Dynamics in Miktoarm Star Copolymers

et al. 2020

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We use broad-band dielectric spectroscopy (BDS) and small-angle X-ray scattering (SAXS) to investigate the impact of architectural asymmetry in the miktoarm star copolymer on the dielectric polymer relaxations. The miktoarm copolymers studied contain one or two polystyrene (PS) chains of constant molecular weight and two identical poly(cis-1,4-isoprene) (PI) chains with varied molecular weights. Using the chains in the PI block as dielectric probes, we find that the architecturally asymmetric miktoarm star copolymer systems (PSPI 2 ) feature distributions in chain relaxation times and dielectric relaxation strengths that are not dependent on molecular weight or morphology, in stark contrast to the effects of morphological confinement observed for symmetric diblock systems (PS-b-PI or PS 2 PI 2 ). Along with evidence from the SAXS measurements regarding phase separation, these results are attributed to influences from chain stretching within the framework of the Gaussian chain model for block copolymer systems. As such, the molecular architecture in block copolymers happens to be a versatile handle to control polymer chain dynamics and, ultimately, the macroscopic physicochemical properties in architecturally complex polymers.

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Section: Methodsmentioning

confidence: 99%

Effects of Asymmetric Molecular Architecture on Chain Stretching and Dynamics in Miktoarm Star Copolymers

et al. 2020

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“…The more pronounced deviations from Gaussian behavior are captured in this simple model by an effectively larger value of the jump distance. A similar situation was discussed for PVE [19], PVME [20], styrene-butadiene-rubber (SBR) and polystyrene (PS) [70]. Additional ingredients were also included to describe the behavior found in complex systems like e.g., confined liquid crystals [71] or proton diffusion in polymer eletrolyte fuel cell membranes [72].…”

Section: Distinguishing the Different Atomic Species: Chemical Dynamic Heterogeneity In Pibmentioning

confidence: 99%

Disentangling Self-Atomic Motions in Polyisobutylene by Molecular Dynamics Simulations

et al. 2021

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We present fully atomistic molecular dynamics simulations on polyisobutylene (PIB) in a wide temperature range above the glass transition. The cell is validated by direct comparison of magnitudes computed from the simulation and measured by neutron scattering on protonated samples reported in previous works. Once the reliability of the simulation is assured, we exploit the information in the atomic trajectories to characterize the dynamics of the different kinds of atoms in PIB. All of them, including main-chain carbons, show a crossover from Gaussian to non-Gaussian behavior in the intermediate scattering function that can be described in terms of the anomalous jump diffusion model. The full characterization of the methyl-group hydrogen motions requires accounting for rotational motions. We show that the usually assumed statistically independence of rotational and segmental motions fails in this case. We apply the rotational rate distribution model to correlation functions calculated for the relative positions of methyl-group hydrogens with respect to the carbon atom at which they are linked. The contributions to the vibrational density of states are also discussed. We conclude that methyl-group rotations are coupled with the main-chain dynamics. Finally, we revise in the light of the simulations the hypothesis and conclusions made in previously reported neutron scattering investigations on protonated samples trying to address the origin of the dielectric β-process.

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“…In fact, polymer blending is an attractive industrial technique because it allows the properties of products to be controlled by adjusting the blending composition during the melt‐blending process, which is simpler than new‐polymer synthesis . When evaluating the practical usefulness of polymer blends, functionality and performance are often the properties of interest . The crystallization behavior of a polymer blend is another important feature as it determines the molding cycle time of polymer products.…”

Section: Introductionmentioning

confidence: 99%

“…Generally, new materials can be fabricated by blending different polymers, thereby combining their properties. [1][2][3][4][5] In fact, polymer blending is an attractive industrial technique because it allows the properties of products to be controlled by adjusting the blending composition during the meltblending process, which is simpler than new-polymer synthesis. [2,4] When evaluating the practical usefulness of polymer blends, functionality and performance are often the properties of interest.…”

Section: Introductionmentioning

confidence: 99%

“…[2,4] When evaluating the practical usefulness of polymer blends, functionality and performance are often the properties of interest. [2,3] The crystallization behavior of a polymer blend is another important feature as it determines the molding cycle time of polymer products. In order to achieve a short molding cycle, polymers should crystallize at high temperatures.…”

Section: Introductionmentioning

confidence: 99%

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High‐temperature crystallization of immiscible polymer blends induced by the shear flow in injection molding

Hirai

Matsunaga

Sato

et al. 2019

Polymer Crystallization

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The crystallization behavior of a polymer blend is thoroughly investigated by considering its melt‐flow history. Poly(ethylene terephthalate) (PET) is found to crystallize at high temperature through shear flow during injection molding when blended with immiscible polyamide 6. Wide‐angle X‐ray scattering experiments reveal that the PET in the blend is better oriented than pure PET because phase separation enhances shear stress during injection molding. Differential scanning calorimetry shows that the crystallization temperature (Tc) of PET (blend) is sensitive to its melt‐flow history. PET (blend) crystallizes at a temperature lower than that of pure PET in pellets prior to injection molding; however, following injection molding, the Tc of PET (blend) is higher than that of pure PET. In particular, high shear conditions, such as in low‐temperature molding, facilitate the high‐temperature crystallization of PET. Therefore, phase separation enhances molecular‐chain orientation and promotes the crystallization of PET.

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Applying Polymer Blend Dynamics Concepts to a Simplified Industrial System. A Combined Effort by Dielectric Spectroscopy and Neutron Scattering

Cited by 11 publications

References 41 publications

Effects of Asymmetric Molecular Architecture on Chain Stretching and Dynamics in Miktoarm Star Copolymers

Effects of Asymmetric Molecular Architecture on Chain Stretching and Dynamics in Miktoarm Star Copolymers

Disentangling Self-Atomic Motions in Polyisobutylene by Molecular Dynamics Simulations

High‐temperature crystallization of immiscible polymer blends induced by the shear flow in injection molding

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