Deuterated poly butadiene

Fig. 9. A comparison of the late stage scaling function of near critical polybutadiene/polyisoprene (PB/PI) mixtures at T = 55 °C with that of deuterated poly-butadiene/polybutadiene mixture [36], DPB/PB and of an iso-butyric acid/water mixture [181] I/W. Note the asymptotic exponents F(x < 1) ocx and F(x > 1) ocx-4. From Takenaka and Hash-imoto [180]...

Deuterated poly( 1,4-butadiene) (PB) networks have also been investigated [18-22], The linear precursor chains Mn from 75000 to 116000 g.mol 1) are homogeneously, selectively deuterated in the 1,4 positions, and randomly crosslinked with different types or amounts of crosslinkers. Star precursor chains deuterated at the center have also been used. 

Constant-time imaging of H in solids has been applied in combination with MAS for line narrowing [Cor3, Cor4]. The images were recorded for a dynamically stressed poly(isoprene) phantom and of poly(butadiene) in two poly(butadiene)/poly(styrene) blends. Spectroscopic MAS imaging has also been tested on deuterated polymers to probe differences in molecular moblity from the lineshape of the rotary-echo envelope... 

This suggests that these structures, which are the reason for the clear separation of the time scales of the local chain motion and the isotropization in PEMA, are significantly affected by the presence of the nanoparticle. One can compare this effect with the significant reduction in the chain reptation in star polymers, where the star point does not move and chain motion can only occur via arm-retraction [45]. In fact, from NMR on selectively deuterated four-arm star poly(butadiene), Brereton el al. [46] found a similar behavior, namely almost uniform dynamics for the middle part of the arm, yet significantly shorter correlation times for the chain ends. Our work also motivated computer simulation of chain dynamics of grafted chains. It was found that the repeat units at the end relax faster than units further inside along the chain, as previously observed for planar brushes but at variance with theoretical expectations [47]. 

Studies both with model compounds and deuterated polymers have shown that, as with the poly butadienes, isomerization is not accompanied by double bond migration. 

X for this system was essentially negligible however, at higher temperatures X became negative. This was attributed to the copolymer effect rather than the existence of specific interactions. The poly butadienes were treated as random copolymers of 1,4- and 1,2-addition units, and there are deuterated and hydrogenous homologues in the mixture, i.e. there are four different types of monomer segment. A, B,C and D. Using the copolymer theory of ten Brinke et al. [30], then % can be written as ... 

Polymer (B) poly(styrene-6-butadiene) (completely deuterated) 2009WI2... 

Figure 4.33. Light scattering patterns obtained after quenching an initially homogeneous mixture of deuterated and normal poly-1,4-butadiene into the two-phase region of the phase diagram. Times after quenching to 322 K are A, 200 s O, 5300 s o, 9800 s , 17 600 s , 46 300 s and A, 84 700 s. After Bates and Wiltzius (1989).

Notes The values of A, B, and C and thus of y are based on a reference volume Vre/ = 0.1 nm Polymer notation A d- label preceding the polymer acronym indicates a per-deuterated polymer partially deuterated polymers are labeled as dy, df, etc., for selective deuteration of 3, 4, etc., hydrogens. Numbers in subscripted parentheses after the polymer name indicate the primary comonomer fraction, e.g., SPB(6s) is a saturated polybutadiene with 66 mol% butadiene Polymer acronyms P2VP poly(2-vinyl pyridine), P4MS poly(4-methylstyrene), PBMA poly(n-butyl methacrylate), PCHA poly(cyclohexyl acrylate), PEB poly(ethyl butylene), PIB polyisobutylene, PI polyisoprene, PMMA poly(methyl methacrylate), PPMA poly(n-pentyl methacrylate), PP polypropylene, HHPP head-to-head polypropylene, PS polystyrene, PVME poly(vinyl methyl ether), PXE poly(2,6-dimethyl-l,4-phenylene oxide), SPB saturated polybutadiene, SPI saturated polyisoprene... 

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