Deuterated poly ethylene

Figure 3.13 shows NMR spectra of different components observed at room temperature for phenylene deuterated poly(ethylene terephthalate) films which were prepared by pressing the polymer melted at 280°C into a mould left at room temperature [24]. The spectra of the crystalline, the mobile glassy and the noncrystalline components, were selectively recorded by the subtraction method using differences in Ti, since their Tj values differed by more than one order from each other. It should be noted here... 

Fig. 3.13. Observed and simulated NMR spectra of different components for the phenylene deuterated poly(ethylene terephthalate) films, measures at 25°C. (Ref. 24.)...

Demixing, Fig. 6 (a) Volume fraction of deuterated poly (ethylene propylene), dPEP full dots), and protonated PEP (open circles) versus depth, for a degree of polymerization N 2,300 for both constituents, after a 4 h quench to r = 294 K (Tc = 365 K). Profiles are obtained with time-of-flight forward recoil spectroscopy. The dashed line indicates the surface domain thickness (f). (b) Plot showing the growth of the surface domain thickness (t) oc (From Krausch et al. [20])... 

Figure 5.5. The surface enrichment profile (solid line) of deuterated poly(ethylene propylene) at the surface of a blend with normal poly(ethylene propylene), measured by neutron reflectivity. The degree of polymerisation of each component was 2250 and the sample was annealed at 70 °C. The depth is normalised by the bulk correlation length and the dashed line is the prediction of equation (5.1.11). After Norton et al. (1995).

Demixing, Figure 6 (a) Volume fraction of deuterated poly(ethylene... 

For deuterated poly(ethylene) in a protonated poly(ethylene) matrix with molecda weight ca. 100000 1 neutron scattering measuremoits (21). All sam de solution were blended in ortho dichlorobenzene, quoidied rapidfy from the melt Mid measmed at 25°C (298.2 K) (concaitration of tagged molecides < 5%). 

Fig. XI-7. Volume fraction profile of 280,000-molecular-weight poly(ethylene oxide) adsorbed onto deuterated polystyrene latex at a surface density of 1.21 mg/m and suspended in D2O, from Ref. 70.

In a recent investigation along the same lines, Graessley and coworkers [8] used a series of asymmetric three-arm poly(ethylene-aZt-propylene) stars, obtained by hydrogenation or deuteration of the corresponding asymmetric po-... 

Silica hydrolysis-condensation of alkoxysilane-terminated chains of various polymers (PB, poly(propylene)-glycol, poly (ethylene)-glycol) leads to the formation of silica nodules. Hybrid (organic-inorganic) nanocomposite rubbery materials are obtained in this way. These materials have been swollen by various deuterated solvents, in order to probe the order induced in the polymer matrix under stress [80]. 

Fully deuterated linear poly(ethylene) (PE) has been investigated also via various 2H NMR techniques below Tm, i.e. in the semi crystalline state [83, 84]. The crystallinity ratio was measured as a function of temperature and it was shown that the motions are highly restricted in the amorphous regions of PE. It was shown that the onset of 3 and a transitions (at which mobility appears in the crystalline phase) may be observed by 2H NMR on raising the temperature. This onset of local motions in the crystalline phase is related to the chain relaxation process quoted previously. 

Polymer (B) poly(ethylene-co-l-butene), deuterated 2008KO... 

PDMS polydimethylsiloxane, PE polyethylene, PVP polyfiV-vinylpyrrolidone), PEP polyfethyl-ene propylene), dPEP deuterated polyfethylene propylene), PLA polyfc.L-lactide), PEO poly (ethylene oxide)... 

Surface-directed spinodal decomposition was first observed in an isotopic polymer blend (Jones et al. 1991) thin films of a mixture of poly(ethylene-propylene) and its deuterated analogue were annealed below the upper critical solution temperature and the depth profiles measured using forward recoil spectrometry, to reveal oscillatory profiles similar to those sketched in figure 5.30. Similar results have now been obtained for a number of other polymer blends, including polystyrene with partially brominated polyst)u-ene (Bruder and Brenn 1992), polystyrene with poly(a-methyl styrene) (Geoghegan et al. 1995) and polystyrene with tetramethylbisphenol-A polycarbonate (Kim et al. 1994), suggesting that the phenomenon is rather general. 

During the years 1992-1998, numerous publications emerged from Prof. Graessley s laboratory. The model PEs with different stmctures (see Fig. 18.10) were commercial (e.g., HDPE or PP) or from laboratory (e.g., hydrogenation/deuteration of diolefins, anionic reaction for PIB, Z-N catalysis using a V-based catalyst in Cg for poly (ethylene-co-a-olefin) or later a metallocene catalyst. The thermodynamic properties of numerous PO blends were extracted from the pressuie-volume-temperature (PVT) data (Walsh et al. 1992 Krishnamoorti et al. 1996) or from SANS results (Krishnamoorti et al. 1994, 1995 Graessley et al. 1994, 1995 Reichart et al. 1997 Alamo et al. 1997). 

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