isotàctics

Isotàctics refers to a type of stereoisomerism in polymers. In an isotactic polymer chain, all the side groups are arranged on the same side of the polymer backbone. This regular arrangement of side groups leads to a highly ordered crystalline structure.

To illustrate, consider a polymer formed from monomers with a chiral center. In an isotactic polymer, the configuration at each chiral center is the same, either all R or all S. This uniformity allows the polymer chains to pack closely and efficiently, resulting in materials with high tensile strength, rigidity, and melting points. Examples of isotactic polymers include isotactic polypropylene and isotactic polystyrene. The synthesis of isotactic polymers often requires specific catalysts, such as Ziegler-Natta catalysts, to control the stereochemistry during polymerization. The properties of isotactic polymers are significantly different from their atactic counterparts, where the side groups are arranged randomly along the backbone.