1,4-Polyisoprene hydrogenated

In this study, the effects of the variations in block sequence and composition (and thus relative block length) on the material properties of two series of triblock copolymers has been investigated. One of the blocks, the hydrogenated polybutadiene (HB), is semicrystalline, and the other block, the hydrogenated polyisoprene (HI) is rubbery at room temperature. Thus in one series, the HBIB block copolymers, the end blocks are semi-... 

The hydrogenation of polyisoprene [55] provides the equivalent of poly (ethylene-a//-propylene) or PEP, typically with low levels of a 3-methyl-1-butene repeat unit due to 3,4 incorporation of isoprene during the anionic polymerization (Scheme 23.5). Hydrogenated polyisoprene is amorphous regardless of the microstructure of the polymer prior to hydrogenation. 

In the class of other homopolyolefins also can be included poly(propylene-a/f-ethylene) or hydrogenated polyisoprene, CAS 127883-08-3. The structure of the polymer is indicated below, together with that of polyethylene and polypropylene, shown for... 

Esterified polystyrene-co-maleic anhydride Polyethylene-co-propylene Poly(ethylene-co-propylene diene-modified) Poly(ethylene-co-propylene-co-olefin diene-modified) Hydrogenated polystyrene-co-butadiene Hydrogenated polystyrene-co-isoprene Hydrogenated polyisoprene. 

There is one additional group of polymers which is derived from this chemistry, the hydrogenated polydienes. Hydrogenated polyisoprenes [41] are chemically equivalent to an alternating copolymer of ethylene and propylene when polymerized in a 1,4 configuration and would thus be expected to exhibit behaviour which is very similar to that of OCPs. Similar characteristics can be achieved with polybutadiene... 

Figure 6.8 Points are the values of app) determined with a diblock copolymer of deuterated polystyrene and hydrogenous polyisoprene, dissolved in a solvent that is a mixture of hydrogenous and deuterated cyclohexane. The contrast factor Y, defined by (6.71), depends on the proportions of the two isotopic species in the solvent. The curve is the theoretical parabola calculated according to Equation (6.70) with best-fitting val-...

HPI-y [1,26,74] hydrogenated polyisoprene where 3,4 content of parent polyisoprene... 

The polymer used in the study was hydrogenated polyisoprene, i.e. alternating poly(ethylene-propylene) (PEP) and its single-end-functionalized derivatives, which were synthesized by the anionic polymerization scheme.One derivative contains a tertiary amine group capped at one end of the chain (amine-PEP). The second has a strongly polar sulphonate-amine zwitterion at the end of the chain (zwitterion-PEP). The parent PEP and its end-functionalized derivatives are model polymers, which have been well characterized previously using various experimental techniques.The ratio M y/Mn was well below 1.1 for samples in the study. 

Tanaka and co-workers [52] determined the distribution of as-1,4 and trans-1,4 units in 1,4 polyisoprenes using C-NMR spectroscopy. Thay found that c/s-1,4 and trans-1,4 units are distributed almost randomly along the polymer chain in cis-trans isomerised polyisoprenes, and that chicle is a mixture of cis-1,4 and trans-1,4 polyisoprenes. These workers [53] also investigated the C-NMR spectra of hydrogenated polyisoprenes and determined the distribution of 1,4 and 3,4 units along the polymer chain for w-butyl lithium catalysed polymers. They confirmed that these units are randomly distributed along the polymer chain. Polymers did not contain appreciable amounts of head-to-head or head-to tail 1,4 linkages. 

A similar series of experiments were carried out on mixtures of deuterated polybutadiene (PBD) and hydrogenous polyisoprene (PIH). The PBD had a content of 1,2-units of 12-28% and the PIH had a 3,4-unit content of 7-15%. For a fixed temperature, % was observed to decrease as the content of 1,2-units in PBD increased and to increase as the content of 3,4-units in the PIH increased. Although the change in % with microstructure is small ( 10" ), it was pointed out that the net interaction parameter is % multiplied by the degree of polymerisation, and hence small changes in % can still produce significant effects. Furthermore, changes in microstructure influence the en-tropic part of % (i.e. a in the empirical expression for y) more than the enthalpic part b). 

Tong, et al.(21) and Ye, et al.(22,23) report sedimentation of 4.0 nm surfactant-coated calcium carbonate particles through monodisperse hydrogenated polyiso-prenes in decane. Unmodified hydrogenated polyisoprene is nonabsorbing to the coated carbonate spheres. Addition of an end-terminal amino group yields an... 

Figure 2.12 Sedimentation coefficients of 4.0 nm radius coated calcium carbonate microspheres through solutions of nonadsorbing hydrogenated polyisoprene, molecular weights (O) 17.5, ( ) 26, ( ) 33, and (0) 88 kDa, based on experiments of Tong, et a/. (21).

Figure 2.13 Sedimentation coefficient of 4.0 nm radius coated CaC03 microspheres in (i) solutions of adsorbing 25 kDa amine-terminal hydrogenated polyisoprene ( ), and (ii) solutions of nonadsorbing unmodified polyisoprene ( , dashed line), based on experiments of Ye, et al. 22). The two solid lines, which are very nearly indistinguishable on the scale of the figure, show stretched-exponential fits to s(c) and to the reported viscosity of these solutions(22).

Raju, et al. report an extremely extensive set of measurements of the dynamic moduli of linear and star polymers in systems ranging from the moderately concentrated up to the melt(25). The complete study examined linear polymers fully hydrogenated polyisoprene, polyisoprene, polystyrene, polybutadiene, and fully hydrogenated polybutadiene, as well as three-arm and four-arm polybutadiene stars, a total of 19 polymers having molecular weights between 4.6 and 860 kDa, at various temperatures. 

To check the correctness of this interpretation von Schooten and co-workers [7] examined the IR spectrnm between 13 and 14 pm of ethylene-propylene copolymers prepared with varions catalyst systems and compared them with the spectra of some model componnds, namely 2,5-dimethylhexane, 2,7-dimethyloctane, 4-methylpentadecane, 4-n-propyltridecane, polypropylene, polyethylene, polybutene-1 and hydrogenated polyisoprene, the last being considered as an ideally alternating ethylene-propylene copolymer. 

Significant differences are, however observed between the various spectra in the wavelength region from 13.0 to 13.7 pm. None of the copolymer spectra shows a clear shoulder at 13.53 pm where hydrogenated polyisoprene shows maximum absorption. 

Rohm GmbH [12] further reported the synthesis of a VI improver that was prepared from isodecyl methacrylate, Ci6-ig alkyl methacrylates, and methyl methacrylate. The Vl-improving property of the product was further enhanced by the addition of polyolefins and hydrogenated styrene-diene copolymer and/or by grafting hydrogenated polyisoprene onto the product. 

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