Propyl end groups

Both P-hydride transfers result in polypropene molecules with one vinylidene and one n-propyl end group. The two transfers are zero- and first-order, respectively, in monomer. P-Hydride transfer yields vinyl end groups in ethylene polymerization. 

Polymerization of propylene with complex 5 (Table 4) at atmospheric pressure produces an atactic polypropylene having the same features regarding the temperature and Al Zr ratio as for ethylene. The H and 13C-NMR spectroscopic analysis of polypropylene reveals only vinyl/isopropyl, but no vinylidene/n-propyl, end groups, similar to the polymers obtained with zirconocenes [67,68]. Polymers with these end groups may be formed from at least three different mechanisms. The first involves an allylic C-H activation of propylene, the second, a /1-methyl elimination, and the third, a /1-hydrogen elimination from a polymer chain in which the monomer inserts in a 2,1 fashion [69]. Since in the... 

In this chapter 1H and 13C NMR spectra of polystyrene are analysed utilizing styrene oligomers having propyl end groups. 

Styrene oligomers having propyl end groups were prepared by initiating oligomerization with ethyllithium and terminating with 1-bromopropane in ethyl ether ... 

The styrene dimer with propyl end groups has the end methyl (A), end methylene (B), external methylene (C), end methine (D) and inner methylene carbons (E) in the main chain and the end phenyl group (i) as the side chain. The trimer has one new type... 

While most molecular solid semiconductors are end-to-end symmetric, a recent publication focuses on thiophene oligomers with two different hydrocarbon end groups (Figure 5.3.3). This work also emphasizes the desirability of mesophase transitions in the processing to make films. Terthiophene with a hexynyl and a propyl end group and quaterthiophene with a propyl and hexynyl end group both exist in smectic phases at room temperature. Time-of-flight mobilities for these phases approach 0.1 cmWs [34]. 

Main conformational changes for meso and racemic PS2 (H propyl end group, R phenyl group)... 

The styrene dimer with propyl end groups has the end methyl (A), end methylene (B), external methylene (C), end me thine (D) and inner methylene carbons (E) in the main chain and the end phenyl group (i) as the side chain. The trimer has one new type of carbon atom, i.e., inner methine (D ), and the inner phenyl group (ii) along with the carbons and the phenyl group contained in the dimer. Furthermore, the tetramer possesses a central methylene carbon (F), and the pentamer possesses a central methine (D ) and a central phenyl group (iii). 

Where P is the polymer chain, to form the vinylidene end-group. This is followed by propagation to produce the propyl end-group. 

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