Segmental Dynamics of Bulk and Silica-Adsorbed Poly(methyl acrylate)-<i>d</i><sub>3</sub> by Deuterium NMR:  the Effect of Molecular Weight

Lin, Wuu-Yung; Blum, Frank D.

doi:10.1021/ma971725z

Cited by 52 publications

(50 citation statements)

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“…18 This restricted chain motion was indicative in various polymer nanocomposites by nuclear magnetic resonance (NMR) spectroscopy experiments. [5][6][7][8]19,20 In addition, the existence of an "interphase" with the property between those of the BPL and the bulk has been hypothesized as the origin of long-range propagations of the effects of the BPL. 21−25 However, it is challenging to distinguish the bound polymer chains or the interphase from the bulk experimentally, because they are all composed of the same component.…”

mentioning

confidence: 99%

Nanostructures and Dynamics of Macromolecules Bound to Attractive Filler Surfaces

Jiang¹,

Endoh²,

Koga³

et al. 2015

ACS Macro Lett.

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We report in situ nanostructures and dynamics of polybutadiene (PB) chains bound to carbon black (CB) fillers (the so-called "bound polymer layer (BPL)") in a good solvent. The BPL on the CB fillers was extracted by solvent leaching of a CB-filled PB compound and subsequently dispersed in deuterated toluene to label the BPL for small-angle neutron scattering and neutron spin echo techniques. The results demonstrate that the BPL is composed of two regions regardless of molecular weights of PB: the inner unswollen region of ≈ 0.5 nm thick and outer swollen region where the polymer chains display a parabolic profile with a diffuse tail. In addition, the results show that the dynamics of the swollen bound chains can be explained by the so-called "breathing mode" and is generalized with the thickness of the swollen BPL. P olymer nanocomposites have been of great interest to the broad materials community for at least the last three decades. 1 The addition of nanoparticles to polymers affects the overall rheological and mechanical properties mainly due to the creation of a "bound polymer layer (BPL)" on a particle surface. 2−10 The most thorough experimental and theoretical studies on BPLs have been carried out on carbon black (CB)-filled rubber systems 11−16 used for automobile tires. A nanometer-thick BPL is typically formed on the CB surfaces and is resistant to dissolution even in a good solvent. 17 In theory, the interactions between polymers and particle surfaces restrict a molecular motion which correlates with increased resistance to mechanical deformation as compared to free polymers that locate away from the particle surface. 18 This restricted chain motion was indicative in various polymer nanocomposites by nuclear magnetic resonance (NMR) spectroscopy experiments. [5][6][7][8]19,20 In addition, the existence of an "interphase" with the property between those of the BPL and the bulk has been hypothesized as the origin of long-range propagations of the effects of the BPL. 21−25 However, it is challenging to distinguish the bound polymer chains or the interphase from the bulk experimentally, because they are all composed of the same component. 25,26 Hence, a molecular scale description of real conformations of the bound polymer chains, which is crucial for a better understanding of the reinforcement mechanism at the interface, remains unclear. 7,27 To overcome this difficulty and provide detailed nanometerscale descriptions at the polymer/filler interface, we use smallangle neutron scattering (SANS) and neutron spin echo (NSE). In addition, we use simplified industrial polybutadiene (PB)/CB nanocomposites as a model. A novel aspect of CB along with its practical importance is the scattering length density that is nearly identical to those of deuterated solvents or polymers, allowing "contrast matching" neutron scattering experiments 28 to gain information about the bound polymer chains selectively. Furthermore, as will be discussed later, the PB bound layer on the CB filler can be considered as a "slab" config...

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confidence: 99%

Nanostructures and Dynamics of Macromolecules Bound to Attractive Filler Surfaces

Jiang¹,

Endoh²,

Koga³

et al. 2015

ACS Macro Lett.

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“…Furthermore, Lin and Blum reported that the relaxation time of polymethacrylate tethered on silica particles was the same as that of bulk polymethacrylate. 17,18 In summary, the EP soft segments of the block copolymers (SEP and SEPS) exhibited two T 1 components, whereas the EP copolymer had only a fast T 1 component. Above ca 20°C, fast mobile EP segments exist in SEP and SEPS, which have the same motional behavior as the EP copolymer.…”

Section: Resultsmentioning

confidence: 91%

“…Similar observations have been also reported in a number of systems, such as poly(styrene-b-butadiene-b-styrene), 9 segmented polyesters 15,16 and polymethacrylate tethered on silica particles. 17,18 Figure 2(a) shows the temperature dependence of the relaxation time for component A. For all the samples used, T 1 minima for component A are observed at ca 30°C.…”

Section: Resultsmentioning

confidence: 99%

²H NMR spin relaxation study of the soft segment motion in alternating ethylene–propylene copolymers

Nakajima

Akiyama

Furuya

2001

Magnetic Reson in Chemistry

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We synthesized three partially deuterated polymer samples, namely a poly(ethylene-alt-propylene) (EP) alternating copolymer, a poly(styrene-b-EP) diblock copolymer (SEP) and a poly(styrene-b-EP-b-styrene) triblock copolymer (SEPS). The 2 H spin-lattice relaxation time, T 1 , of EP soft segments above their glass transition temperature was measured by solid-state 2 H NMR spectroscopy. It was found that the block copolymers had a fast and a slow T 1 component whereas EP copolymer had only a fast component. The fast T 1 components for SEP and SEPS are similar to the T 1 value of EP above ca 20• C. The slow T 1 component for SEP and SEPS exhibited a minimum at 60• C and approached the value of the fast component near the T g of polystyrene. The motional behavior of the EP units for SEP is similar to that of SEPS over the entire range of temperature.

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“…In this experiment, when the hydrolysis of TEOS was catalyzed by hydrochloric acid, the reaction was fast and stable. Instead, if NH 4 OH was employed as the catalyst, the rate of hydrolysis was relatively slow and precipitation was apt to occur. Generally, the pH value was about 2 in solution of a prehydrolyzed TEOS, and the pH value of the resultant mixed solution increased gradually with an increase in polymer content (e.g., pH ϳ 3 in a 50/50 system and ϳ 6.5 in a 95/5 system).…”

Section: Effect Of Ph Valuementioning

confidence: 99%

Preparation of polymer/silica nanoscale hybrids through sol‐gel method involving emulsion polymers. II. Poly(ethyl acrylate)/SiO₂

Tong

Tang

Feng

et al. 2002

J of Applied Polymer Sci

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Poly(ethyl acrylate) (PEA)/SiO 2 hybrids with different compositions were prepared under different casting temperatures and pH values. Their morphology as investigated by transmission electron microscopy (TEM) shows that samples with different compositions have different morphologies. When the SiO 2 content is lower, PEA is the continuous phase and SiO 2 is the dispersed phase. At higher SiO 2 content, the change in phase morphology takes place, nd PEA gradually dispersing in the form of latex particles in SiO 2 matrix. Change in phase morphology depends mainly on the time the sol-gel transition occurs. At suitable casting temperature and pH value, PEA/SiO 2 in 95/5 and 50/50 hybrids with even dispersion was obtained.

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Segmental Dynamics of Bulk and Silica-Adsorbed Poly(methyl acrylate)-d₃ by Deuterium NMR: the Effect of Molecular Weight

Cited by 52 publications

References 24 publications

Nanostructures and Dynamics of Macromolecules Bound to Attractive Filler Surfaces

Nanostructures and Dynamics of Macromolecules Bound to Attractive Filler Surfaces

²H NMR spin relaxation study of the soft segment motion in alternating ethylene–propylene copolymers

Preparation of polymer/silica nanoscale hybrids through sol‐gel method involving emulsion polymers. II. Poly(ethyl acrylate)/SiO₂

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Segmental Dynamics of Bulk and Silica-Adsorbed Poly(methyl acrylate)-d3 by Deuterium NMR: the Effect of Molecular Weight

Cited by 52 publications

References 24 publications

Nanostructures and Dynamics of Macromolecules Bound to Attractive Filler Surfaces

Nanostructures and Dynamics of Macromolecules Bound to Attractive Filler Surfaces

2H NMR spin relaxation study of the soft segment motion in alternating ethylene–propylene copolymers

Preparation of polymer/silica nanoscale hybrids through sol‐gel method involving emulsion polymers. II. Poly(ethyl acrylate)/SiO2

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Product

Resources

About

Segmental Dynamics of Bulk and Silica-Adsorbed Poly(methyl acrylate)-d₃ by Deuterium NMR: the Effect of Molecular Weight

²H NMR spin relaxation study of the soft segment motion in alternating ethylene–propylene copolymers

Preparation of polymer/silica nanoscale hybrids through sol‐gel method involving emulsion polymers. II. Poly(ethyl acrylate)/SiO₂