Repeating units, configurational

IUPAC recommendations suggest that a copolymer structure, in this case poly(methyl methacrylate-co-styrene) or copoly(methyl methacrylate/slyrene), should be represented as 1. The most substituted carbon of the configurational repeat unit should appear first. This same rule would apply to the copolymer segments shown in Section 7.1. However, as was mentioned in Chapter I, in this book, because of the focus on mechanism, we have adopted the more traditional depiction 2 which follows more readily from the polymerization mechanism. 

Orderliness of the succession of configurational repeating units in the main chain of a regular macromolecule, a regular oligomer molecule, a regular block, or a regular chain. 

Regular macromolecule in which essentially all the configurational (repeating) units are identical. 

Note In an isotactic macromolecule, the configurational repeating unit is identical with the configurational base unit. 

Note In a syndiotactic macromolecule, the configurational repeating unit consists of two configurational base units that are enantiomeric. 

Unless otherwise stated, the drawings of configurational base units, configurational repeating units, stereorepeating units, etc., provide information regarding relative configurations. 

It is immaterial whether (1) or (2) is taken as the configurational repeating unit and ster corep eating unit of isotactic polypropene (see Definition 1.7) this is so because the two infinite chains, one built up of identical configurational units (1) and the other built up of... 

Regular polymer, the molecules of which have essentially all identical configurational repeating units. 

For the polymer -[-CH(COOR)CH(CH3)-hp, if only the ester-bearing main-chain site in each constitutional repeating unit has defined stereochemistry, the configurational repeating unit is (7) and the corresponding isotactic polymer is (8). 

In the corresponding syndiotactic case, the configurational repeating unit is (9) and the syndiotactic polymer is (10) ... 

Regular block that can be described by only one species of configurational repeating unit in a single sequential arrangement. 

Polymerization of penta-l,3-diene by 1,4-addition with an optically active catalyst gives an optically active polymer comprising configurational repeating units with predominantly one type of chirality centre. 

Structural disorder resulting from the statistical co-crystallization of different configurational repeating units (see Fig. 2). 

The pioneering work of Natta and co-workers introduced the concept of tacticity, i.e. the orderliness of the succession of configurational repeating units in the main chain of a polymer. For example, in polypropene (polypropylene), possible steric arrangements are (shown in Fischer projections displayed horizontally) ... 

Tacticity - The orderliness of the succession of configurational repeating units of a macromolecule or oligomer molecule. In a tactic macromolecule essentially all the configurational repeating units are identical with respect to directional sense. See Configurational repeating unit, Isotactic, Syndiotactic. [8]... 

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