Poly(ethylene oxide) Dynamics in Blends with Poly(vinyl acetate): Comparison of Segmental and Terminal Dynamics

Abstract

Deuterium NMR at Larmor frequencies of 15.6 and 76.7 MHz was used to study the segmental dynamics of perdeuteriopoly(ethylene oxide) (d4PEO) in miscible blends with poly(vinyl acetate) (PVAc). Blends with PEO compositions of 2% and 50% were studied. The segmental dynamics of PEO are 9 orders of magnitude faster than the PVAc segmental dynamics for a 2% PEO blend near the blend T g and could be described by the Lodge−McLeish model with a self-concentration of 0.3. The segmental dynamics of PEO in blends with PVAc show a weaker temperature dependence than the terminal dynamics of PEO in the same blends. We also compare the segmental and terminal dynamics of components in several other miscible polymer blends. For the fast component in a blend, it is commonly observed that terminal relaxation has a stronger temperature dependence than segmental relaxation. This effect correlates with the difference between the T g values for the pure components and also with the ratio of the activation energies of the segmental dynamics for the two components in the blend.

Molecular dynamic in binary mixtures and polymer blends with large difference in glass transition temperatures of the two components: A critical review

“…S6 of SI, the result holds for a wide range of temperatures extending to well below the glass transition of the PMMA matrix, where the segmental relaxation times of PMMA are about 12 orders of magnitude longer than  2 of PEO. Similar behavior is observed by deuteron NMR in PEO blends with PVAc (polyvinyl acetate) [59]. In the range -9 log( 2 /s) -11.8, the  2 of PEO in 2% PEO blend differs little from that in 50% PEO and 100%PEO blends by about half a decade and one decade respectively.…”

“…A different scenario for the dynamics presents itself in highly asymmetric binary mixtures [29,[77][78][79][81][82][83][84][85]87,103] and polymer blends [20][21][22][23][24][25][26][27][28]31,32,[39][40][41][42][43][44][45][46][47][48][49][50][51][52][54][55][56][57][58][59][60][61][62][63][64][65][66] where the difference in the glass transition temperatures, T g = T g1 -T g2 , is large. If the concentration c 2 of the low-T g component is not...…”

Longer-scale segmental dynamics of amorphous poly(ethylene oxide)/poly(vinyl acetate) blends in the softening dispersion

“…the enhanced local concentration due to chain connectivity). 4,19,20 The coupling model (CM) considers not only the presence of different local environments due to CF but also the change of intermolecular coupling due to the presence of the other component. 21 Recently, a few models that combine SC and CF effects were proposed to describe the segmental dynamics in polymer blends.…”

“…39 Moreover, the microstructure and dynamics of semicrystalline PEO/PVAc blends with high PEO content were investigated by using smallangle X-ray scattering. 41 On the other hand, the dynamics of PEO in the PEO/PVAc blends have also been studied by deuterium NMR and QENS measurements, 20,38 showing that the PEO dynamics are about 9 orders of magnitude faster than the PVAc dynamics at the blend T g and a crossover temperature was found where the dynamics of PEO change qualitatively from glassforming polymer-like to confined.…”

Consequence of Excess Configurational Entropy on Fragility: The Case of a Polymer-Oligomer Blend

“…Having such similar samples can only be achieved using polymers of the same chemical nature. Thanks to the effect of M n on their physical properties, the reference of a pure system such as the 17-mer is available while it is not in the usual polymer-polymer or molecular liquids mixtures that have been extensively studied in the literature [6,7,8,9,10,11] for other purposes. A comparative study of these two samples is an ideal way to better understand fragility while minimally affecting the system.…”