Poly solid-state dynamics

Crosslinked polymer networks formed from multifunctional acrylates are completely insoluble. Consequently, solid-state nuclear magnetic resonance (NMR) spectroscopy becomes an attractive method to determine the degree of crosslinking of such polymers (1-4). Solid-state NMR spectroscopy has been used to study the homopolymerization kinetics of various diacrylates and to distinguish between constrained and unconstrained, or unreacted double bonds in polymers (5,6). Solid-state NMR techniques can also be used to determine the domain sizes of different polymer phases and to determine the presence of microgels within a poly multiacrylate sample (7). The results of solid-state NMR experiments have also been correlated to dynamic mechanical analysis measurements of the glass transition (1,8,9) of various polydiacrylates. 

Local Dynamics in Polypeptides Studied by Solid State 2H NMR Side Chain Dynamics of Poly(Y-benzyl L-glutamate) and Racemic Poly(Y-benzyl glutamate)... 

First introduced to polymer chemistry by Schaefer and collaborators, CP-MAS spectroscopy has already yielded interesting results in both stractural and dynamic studies. The comparison of spectra in solution and in bulk permits identification of frozen conformations, distinction between spectra of crystalline and amorphous phases and measurement of the rate of several eonformational transitions. For example, the C spectrum of the poly(phenylene oxide), 74, in solution consists of five signals while the CP-MAS spectrum displays six. In the solid state the resonance of the aromatic CH appears split into two components. The phenomenon is attributed to the forbidden rotation of the benzene ring around the O. .. O axis, which makes the two carbon atoms indicated with an asterisk no longer equivalent. 

Beckham and coworkers studied the dynamic mechanical properties of poly(urethane-crown ether rotaxane)s [138]. No difference was observed between the backbone and polyrotaxane, probably because of the low min value (0.02). However, 13C solid-state NMR detected die presence of the crown ether as a mobile structure at room temperature. The same observation was seen in polyrotaxanes with ether sulfone and ether ketone backbones (77-80) [114]. Although no detailed properties were reported, the detection of the liquid-like crown ether provided very important information in terms of mechanical properties, because these properties are the result of molecular response to external forces. For example, mobile crown ethers can play the role of plasticizers and thus improve impact strength. 

A series of poly(cycloalkyl methacrylates) has been investigated by dynamic mechanical analysis and solid-state 13 C NMR in order to characterise the... 

The approach developed in this paper, combining on the one side experimental techniques (dynamic mechanical analysis, dielectric relaxation, solid-state 1H, 2H and 13C NMR on nuclei at natural abundance or through specific labelling), and on the other side atomistic modelling, allows one to reach quite a detailed description of the motions involved in the solid-state transitions of amorphous polymers. Bisphenol A polycarbonate, poly(methyl methacrylate) and its maleimide and glutarimide copolymers give perfect illustrations of the level of detail that can be achieved. 

Rather recently, we have studied the solid-state structure of various polymers, such as polyethylene crystallized under different conditions [17-21], poly (tetramethylene oxide) [22], polyvinyl alcohol [23], isotactic and syndiotactic polypropylene [24,25],cellulose [26-30],and amylose [31] with solid-state high-resolution X3C NMR with supplementary use of other methods, such as X-ray diffraction and IR spectroscopy. Through these studies, the high resolution solid-state X3C NMR has proved very powerful for elucidating the solid-state structure of polymers in order of molecules, that is, in terms of molecular chain conformation and dynamics, not only on the crystalline component but also on the noncrystalline components via the chemical shift and magnetic relaxation. In this chapter we will review briefly these studies, focusing particular attention on the molecular chain conformation and dynamics in the crystalline-amorphous interfacial region. 

For the investigation of the molecular dynamics in polymers, deuteron solid-state nuclear magnetic resonance (2D-NMR) spectroscopy has been shown to be a powerful method [1]. In the field of viscoelastic polymers, segmental dynamics of poly(urethanes) has been studied intensively by 2D-NMR [78, 79]. In addition to ID NMR spectroscopy, 2D NMR exchange spectroscopy was used to extend the time scale of molecular dynamics up to the order of milliseconds or even seconds. In combination with line-shape simulation, this technique allows one to obtain correlation times and correlation-time distributions of the molecular mobility as well as detailed information about the geometry of the motional process [1]. 

The results of a study of the relation between the oriented structure and drawn poly(e-caprolactone) specimens including CaCO particles, their dynamic mechanical properties and line shape analyses of CP MAS NMR spectra are presented. Solid state studies of C NMR study of poly(methyl acrylate) ionomer have been reported. ... 

G.J. Kearley, P. Johansson, R.G. Delaplane J. Lindgren (2002). Solid State Ionics, 147, 237-242. Structure, vibrational-dynamics and first-principles study of diglyme as a model system for poly(ethyleneoxide). 

Molecular dynamics in the solid state of poly hydroxyalkanoic acid)s studies by NMR... 

It is well known that nmr is a powerful means for the study of the dynamics of polymer chains both in solution and in the solid state. The relaxation of 13C nuclei has been extensively employed for this purpose in this and other laboratories. I illustrate here a dilferent and particularly intriguing approach which as yet has seen only very limited application to synthetic polymers. This is deuterium quadrupolar echo spectroscopy, as employed in our laboratory by Dr. Lynn Jelinski and her collaborators (20). The presence of the nuclear electric quadrupole lifts the degeneracy of the two deuterium Zeeman transitions, and in the solid state produces a very broad (ca 200 kHz) powder pattern of transitions which can be interpreted to yield very specific motional information for those carbons labelled with deuterium. In Figure 7 are shown spectra of poly (butylene terephthalate) deuterated on the central carbons of the aliphatic chains ... 

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. 

Dynamic mechanical and NMR investigations of crystals grown from dilute solutions for polymers other than linear polyethylene have been much less extensive. Studies have been reported for the linear polymers polyoxy methylene (3, 40, 94), poly (ethylene oxide) (3, 78), and nylon 6 (42), and the branched polymers polypropylene (40), poly-l-butene (19, 95), poly(4-methyl-l-pentene) (33), poly (vinyl alcohol) (78), and branched polyethylene (78). In addition, dielectric loss measurements have been made on crystal aggregates of poly (ethylene oxide) (23), poly (vinyl alcohol) (68), and polyoxymethylene (3) and mechanical loss measurements have been carried out on polyoxymethylene formed by solid state polymerization (94). 

English AD (1984) Macromolecular dynamics in solid poly(ethylene terephthalate) H and solid state NMR, Macromolecules 17 2182... 

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