syndiotactic in a sentence

1. Commercial synthesis of syndiotactic polypropylene is carried out with the use of a special class of metallocene catalysts.
2. Different metal chlorides allowed the selective production of each form i . e ., syndiotactic, isotactic and atactic polymer chains could be selectively created.
3. If a special catalyst is used in its synthesis it is possible to obtain the syndiotactic version of this polymer, but most industrial polystyrene produced is atactic.
4. The result is that, whereas syndiotactic PS is a semicrystalline material, the more common atactic version cannot crystallize and forms a " glass " instead.
5. A variety of catalysts can polymerise lactide to either heterotactic or syndiotactic polylactide, which as biodegradable polyesters with valuable ( inter alia ) medical properties are currently attracting much attention.
6. It's difficult to find syndiotactic in a sentence.
7. When these associations are stacks of alternating ( " R " ) and ( " S " ) molecules ( as in syndiotactic polymers ) this can be accomplished very efficiently.
8. The geometry of the metallocene catalyst will determine the sequence of chirality in the chain, as in, atactic, syndiotactic, isotactic, as well as average block length, molecular weight and distribution.
9. For example, three distinct " ansa "-zirconocene dichloride catalysts used in the synthesis of polypropylene in the presence of methylaluminoxane ( MAO ) can be used to direct whether the product is syndiotactic, isotactic, or atactic.
10. Isotactic and syndiotactic polymers are instances of the more general class of eutactic polymers, which also includes heterogeneous macromolecules in which the sequence consists of substituents of different kinds ( for example, the side-chains in proteins and the bases in nucleic acids ).
11. A Ziegler-Natta catalyst is able to restrict linking of monomer molecules to a specific regular orientation, either isotactic, when all methyl groups are positioned at the same side with respect to the backbone of the polymer chain, or syndiotactic, when the positions of the methyl groups alternate.
12. If free rotation does not occur before the next monomer adds, the mirror approach will always lead to an isotactic polymer and the non-mirror approach will always lead to a syndiotactic polymer ( Figure 25 ) . " Figure 26 " : Penultimate unit interactions cause monomer to add in a way that minimizes steric hindrance between substituent groups . ( P represents polymer chain .)