izotaktik

Isotactic refers to a specific type of stereoisomerism found in polymers. In an isotactic polymer chain, all of the stereogenic centers along the backbone have the same configuration. This means that if you consider a repeating unit in the polymer chain that has a chiral center, the substituent group on that chiral center will be oriented in the same direction relative to the polymer backbone for every repeating unit. For example, in polypropylene, if the methyl group is pointing up on one carbon atom, it will also be pointing up on all subsequent carbon atoms in the chain. This regular, ordered arrangement of side groups is a key characteristic of isotactic polymers. This structural regularity significantly impacts the physical properties of the polymer, often leading to increased crystallinity, higher melting points, and greater mechanical strength compared to their atactic (randomly arranged) counterparts. The ordered packing of isotactic polymer chains in the solid state facilitates the formation of crystalline structures.