Connectivity and spacing effects in hydrogen-bonding polymer solutions and blends

Painter, Paul C.; Park, Yung; Coleman, M. M.

doi:10.1002/(sici)1097-4628(19981114)70:7<1273::aid-app4>3.0.co;2-j

Cited by 13 publications

(11 citation statements)

References 8 publications

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“…Also included in each of the plots in Figure are predictions of the effective T g of the PACM component (black lines) and the Jeffamine component (green lines) using the Lodge‐McLeish model . The Lodge‐McLeish model, and similar work by Painter and Coleman examines the effects of concentration fluctuations or local dynamic heterogeneity which are a result of chain connectivity. The model uses a modified Fox‐Flory equation, with ϕ being the volume fraction of component A or B:

\frac{1}{T_{g} true(ϕ true)} = \frac{ϕ_{e f f e c t i v e}}{T_{g, A}} + \frac{1 ‐ ϕ_{e f f e c t i v e}}{T_{g, B}}

…”

Section: Resultsmentioning

confidence: 99%

Dynamic heterogeneity in epoxy networks for protection applications

Masser

Knorr

et al. 2016

J of Applied Polymer Sci

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The segmental dynamics and ballistic performance are investigated for a series of thermosetting epoxy networks composed of diglycidyl ether of bisphenol A (DGEBA) cured with mixtures of a rigid cycloaliphatic diamine and a series of flexible propylene oxide diamines. Formulations of DGEBA, cycloaliphatic diamine, and a low molecular weight propylene oxide diamine exhibit miscibility in the fully cured state, resulting in a single glass transition temperature (T g ), described by a Gordon-Taylor relationship. When high molecular weight propylene oxide diamines are used, the monomers are partially miscible, and the resulting cured epoxy exhibits dynamic heterogeneity, as evidenced by dual T g 's. These dynamically heterogeneous systems composed of rigid and flexible domains can exhibit enhanced ballistic impact response when the length scale of the phase separation is small, and the composition is near a phase inversion point. The dynamic heterogeneity also broadens the temperature window for impact performance, which is important for practical applications in military systems.

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\frac{1}{T_{g} true(ϕ true)} = \frac{ϕ_{e f f e c t i v e}}{T_{g, A}} + \frac{1 ‐ ϕ_{e f f e c t i v e}}{T_{g, B}}

…”

Section: Resultsmentioning

confidence: 99%

Dynamic heterogeneity in epoxy networks for protection applications

Masser

Knorr

et al. 2016

J of Applied Polymer Sci

View full text Add to dashboard Cite

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“…It may at first be expected that the concentrations of relaxing species in blends with strong intermolecular interactions are unimodal and distributed rather narrowly around the mean composition. However, the number of hydrogen bonds is strongly affected by chain connectivity and the spacing of functional groups, which effectively reduces the intermolecular hydrogen bonding contribution to the free energy of mixing . The local SHS self-concentration can be enhanced further by intramolecular hydrogen bonding between −OH groups.…”

Section: Resultsmentioning

confidence: 99%

Dielectric Studies of Poly(ethylene oxide)/Poly(styrene-co-p-hydroxystyrene) Blends: Influence of Hydrogen Bonding on the Dynamics of Amorphous Blends

2003

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The segmental dynamics of a poly(styrene-co-p-hydroxystyrene) random copolymer [SHS, 50 wt % HS] and its amorphous, melt-miscible blends with poly(ethylene oxide) were investigated using broadband dielectric relaxation spectroscopy. The fragility of the neat copolymer was found to be close to that of polystyrene with comparable molecular weight, consistent with the idea that intramolecular hydrogen bonding primarily enhances the monomer friction coefficient and Tg, while having little effect on fragility. Despite the large mobility difference between the component polymers, a single cooperative segmental relaxation is observed for the blends (SHS concentration g 60%), demonstrating the coupling ability of intermolecular hydrogen bonds. Blend fragility increased significantly with SHS content, reflecting the combined contribution of the two components. The most intriguing finding was a fast process in blends containing g80 wt % SHS. The available evidence supports its assignment to noncooperative segmental relaxation of PEO repeat units, having some similarities to the modified segmental dynamics of nanoconfined polymers.

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“…It was useful to investigate the specific intra‐ or intermolecular interactions, such as hydrogen bonding16, 17 or electron donor–acceptor complexes with FTIR. Interactions between styrenic polymers and methacrylic polymers are weak and nonspecific.…”

Section: Resultsmentioning

confidence: 99%

Thermal, morphology, and NMR characterizations on phase behavior and miscibility in blends of isotactic polystyrene with poly(cyclohexyl methacrylate)

Chang

Woo

2003

J Polym Sci B Polym Phys

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The miscibility and phase behavior in a binary blend of isotactic polystyrene (iPS) and poly(cyclohexyl methacrylate) (PCHMA) were investigated by differential scanning calorimetry, optical microscopy (OM), and solid‐state 13C cross‐polarity/magic‐angle spinning NMR. The iPS/PCHMA blend was miscible when all compositions showed a single composition‐dependent glass‐transition temperature (Tg) and when the blend went through a thermodynamic phase transition upon heating to above the lower critical solution temperature as determined by OM measurements. The 1H NMR spin‐relaxation times in the laboratory frame (T H1) and in the rotating frame (T H1ρ) for iPS/PCHMA blends with various compositions and neat components were directly measured through solid‐state13C NMR. The results of T H1 indicated that the blends are homogeneous, at least on a scale of 75–85 nm, confirming the miscibility of the system. The single decay and composition‐dependent T H1ρ values for each blend further demonstrated the blends are homogeneous on a scale of 2.5–3.5 nm. The results suggested that iPS and PCHMA are intimately mixed at the molecular level within the blends at all compositions. The tacticity of polystyrene does not seem to adversely influence the miscibility in blends of iPS/PCHMA. © 2003 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 41: 772–784, 2003

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Connectivity and spacing effects in hydrogen-bonding polymer solutions and blends

Cited by 13 publications

References 8 publications

Dynamic heterogeneity in epoxy networks for protection applications

Dynamic heterogeneity in epoxy networks for protection applications

Dielectric Studies of Poly(ethylene oxide)/Poly(styrene-co-p-hydroxystyrene) Blends: Influence of Hydrogen Bonding on the Dynamics of Amorphous Blends

Thermal, morphology, and NMR characterizations on phase behavior and miscibility in blends of isotactic polystyrene with poly(cyclohexyl methacrylate)

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