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Hemisyndiotactic polymers

An analogous method was used to obtain a new class of macromolecular stereoisomers The hemitactic polymers (99-101). This term refers to a head-to-tail vinyl polymer in which the tertiary carbon atoms constitute two distinct series one, which includes monomer units 1,3,5, 7,..., possesses strict steric regularity, whereas the other, with monomer units 2, 4, 6, 8,. .., is completely at random. In such polymers only one in every two tertiary atoms is influenced by an ordering rule 58 and 59 show the schematic structure of the hemiisotactic and hemisyndiotactic polymers where the white circles indicate the positions of disordered s ubstituents. The hemiisotactic polypropylene was obtained by Farina, Di Silvestro, Sozzani and Savar6 (99, 101) by nonste-reoselective reduction,of. isotactic frans-l,4-poly-2-methylpentadiene. [Pg.18]

Figure 3.7 Stereoisomerism of poly(o -olefin)s -[-CH(R)—CH2-]W-. Hemiisotactic and hemisyndiotactic polymers... Figure 3.7 Stereoisomerism of poly(o -olefin)s -[-CH(R)—CH2-]W-. Hemiisotactic and hemisyndiotactic polymers...

See other pages where Hemisyndiotactic polymers is mentioned: [Pg.50]    [Pg.50]    [Pg.50]    [Pg.50]   
See also in sourсe #XX -- [ Pg.50 ]




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