Polymer Chain Dynamics

Polymers Chain dynamics Local viscosity in polymer environments Molecular orientation in solid polymers Migration of excitation energy along polymer chains... 

NMR has not been widely employed to study dynamics in block copolymer melts, although field gradient NMR can provide a wealth of information on the diffusion of block copolymer chains (Fleischer et al. 1993). The orientation of a deuterated homopolymer in a lamellar diblock copolymer (in a glassy state) was determined using 2H NMR by Valic et al. (1994,1995). Other applications of NMR to probe polymer chain dynamics and details of experimental protocols are described by Bovey and Jelinksi (1989). 

Polymer chain dynamics in the solid state Several relaxation time parameters can be distinguished in solid state NMR. For the study of polymer dynamics T2, Tlp and TCP are mostly used. 

Nguyen TQ and Kausch H-H, "Flexible Polymer Chain Dynamics in Elongational Flow", Springer, Berlin, 1999. Reiner M, "Deformation and Flow", Lewis, London, 1948. 

Torsional relaxation of pendant groups, which can occur at temperatures below or above the glass transition temperature (Tg), plays an important role in polymer chain dynamics. Even at low temperatures, despite the fact that... 

The use of NMR relaxation studies in the polymer solutions is well known for the study of polymer chain dynamics, polymer/polymer, polymer/solvent. 

Fig. 13 Velocity dependence of frictional stress for a soft gel sliding on a smooth adhesive solid substrate. The result is based on the molecular picture in Fig. 12, which considers the thermal fluctuation of adsorption and desorption of the polymer chain, (a) The elastic term of the frictional stress of a gel. See text for a description of parameter u. (b) Summation of the elastic term and the viscous term. When v -C Vf, the characteristic polymer adsorption velocity, the elastic term is dominant. At v 2> the viscose term is dominant. Therefore, transition from elastic friction to lubrication occurs at the sliding velocity characterized by the polymer chain dynamics. (Modified from figure 1 in [65])...

Kimmich, R. And Fatkullin, N. Polymer Chain Dynamics and NMR. Vol. 170, pp. 1-113. Kippelen, B. and Peyghambarian, N. Photorefractive Polymers and their Applications. 

These and other facets of the poly(propylene) data as well as similar data for PMMA are discussed with respect to their implications for insight into polymer chain dynamics in the solid state. 

The Coupling Model is consistent with all the properties and has fundamental support from quasielastic neutron scattering and simulations. However, the emphasis of the entire section is on the many properties of component dynamics in HAPB that deserve attention and alternative explanation by researchers in glass transition and polymer chain dynamics and viscoelasticity. This is because the new physics found in the segmental and chain dynamics of components in highly asymmetric polymer blends could possibly revolutionize the current understanding of polymer dynamics and viscoelasticity. 

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