Hydrogen polymers

Types of starting polymers Unhydrogenated precursor Hydrogenated polymer ... 

E. B. Brandes and F. C. Loveless. Dispersants and dispersant viscosity index improvers from selectively hydrogenated polymers. Patent WO... 

For the partially hydrogenated polymers, the reaction was quenched by adding 2-propanol. 

Further confirmation of the structure and tacticity of poly/5-methyl-l,4-hexadiene)was obtained from X-ray diffraction and u-NMR data of its hydrogenated polymer (Scheme 2). The hydrogenated polymer sample showed a highly crystalline pattern (Figure 7), with diffraction spots that were well defined. This pattern was identical to that of isotactic poly(5-methyl-l-hexene) as reported in the literature (26) (measured identity period, 6.2 A lit., 6.33 A). 

The C-NMR spectrum of the hydrogenated polymer sample in CDClj solvent (Figure 8) was identical to that of the polymer we obtained by the direct polymerization of 5-methyl-1-hexene with Et2AlCl/6-TiCl3 AA catalyst (Al/Ti atomic ratio = 1.5, hexane solvent, 30°C). The hydrogenation was essentially complete. 

Hydrogenated polymers have many desirable properties over their parent polymers, although the high cost of hydrogenated products still restricts their widespread application. The following aspects should be considered for the sustainable development of the hydrogenated polymer industry ... 

The development of highly efficient and easily recoverable catalyst systems. Today, the high cost of hydrogenated polymers is due mainly to the cost of the metal catalyst and its recovery operation. 

CHA-CH=CH-CHB-CHA-CH=CH-CHB-. The hydrogenated polymers may analogously be considered —CHA—CH2 CH2—CHB—CHA— CH2—CH2—CHB—. In these cases the complexity of the disubstituted polymer adds to that of the polymers in which the two chain directions are different. In principle 4 two-center, 8 three-center, and 16 four-center sequences must be considered. 

The method has been applied to saturated aromatic and olefin-free mineral oil fractions and hydrogenated polymers cf. Table III and IV). 

Table IV contains data on hydrogenated polymers of propylene, isobutene and cyclohexene obtained by polymerization under various conditions38. The Direct Method (ultimate analysis and molecular weight) shows that the polymers of propylene and isobutene are paraffinic for the estimation of cp the appropriate formulas were used. In the case of the highly cyclic saturated cyclohexene-polymers the formulas for hydrogenated mineral oil fractions were applied. In the table are also given values of q> and Rt determined with the ring analysis diagrams of Figs. 59 and 60 (p. 64-65).

Individual enantiomers of 90 have been prepared by RCM (Section VII.A.l) and polymerized by 8 (R = Ph) at — 30 °C to give a 52% yield of a 74% trans polymer226. Likewise 91, with the same initiator at — 55 °C, gives a 51% yield of 60% cis polymer, with a blocky cis/trans distribution (rtrc = 6.3) the 13C NMR spectrum of the hydrogenated polymer shows it to be atactic326. 

Poly(vinylidene fluoride) (PVDF) is the second most important thermoplastic within the fluoropolymer family after PTFE. Although, both the thermal and chemical stability of PVDF are somewhat lower compared to PTFE, the hydrogenated polymer can be more easily processed with conventional equipment, and it offers an advantageous compromise between quality and price. When the... 

Attempts to reduce PPEs 12 under moderate pressures (2-3 bar H2) at temperatures of around 70-80 °C were unsuccessful. PPEs seem to be very stable chemically, and only when the reduction was performed in an autoclave under drastic conditions successful hydrogenation was observed. Hydrogen pressures of 300-500 bar at temperatures of around 300 °C are necessary for complete reduction of the PPE to the hydrogenated polymer 60 [40]. The yield of 60 is high the aromatic rings are not affected under these conditions and side products are not detected in the colorless materials formed. Attempts to use shorter reaction times, lower temperatures, or lower hydrogen pressures failed, and partially reacted material of undefined structure resulted. 

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