There is an increasing need for environment friendly materials with advanced and improved properties. Polyolefins produced by means of transition metal catalysed polymerisations, as pure hydrocarbons meet the requirements for sustainable development. Advances in novel soluble catalytic systems, with well defined structure, allow the synthesis of novel polymeric materials non accessible with traditional heterogeneous Ziegler-Natta catalysts: cycloolefin copolymers (COC) represent a new class of macromolecules.
The presence of cyclic structures restricts the polymer chain mobility, the resulting rigidity makes these polymers ideal for engineering applications. The introduction of ethylenic unit (E) in the polymer chain allows the tooling of the polymer rigidity and to obtain materials with excellent engineering properties. TOPAS® (Ticona) is a norbornene (N) based COC family, completely amorphous, with excellent transparency, high glass transition temperature (Tg), low water absorption, chemical resistance, birefringence, and dielectric constant. Such properties make TOPAS® ideal as a toner binder resin for laser printers, lenses, barrier-films for packaging and blister packs, in medical and diagnostic applications.
The range of COC properties depend on their morphological structure, which in turn depends on the polymer composition as well as on the polymer chain microstructure and stereoregularity. Hence, the great academic and industrial interest in clarifying: COC microstructure, mainly through NMR spectroscopy; catalyst-copolymer structure; and correlation between properties and copolymer structure.
In this field ISMAC has devoted much time to research both in chemistry and chemical physics and has made first significant contributions: in assigning 13C NMR spectra of E-N copolymers, by combining the comparison of spectra of copolymers synthesized with various catalysts, with special NMR techniques, computational methods to relate conformations and NMR spectra, and ab initio chemical shifts calculations; in clarifying COC microstructure at stereochemical tetrad level; in copolymerisation
mechanism and kinetic studies; in the synthesis and characterization of branched copolymers with improved rehological properties and processability. Molecular dynamics calculations aiming at establishing correlations between polymer properties (as Tg) and polymer composition and microstructure are also under way.
Results will contribute to develop novel and more efficient catalytic systems for olefin polymerization with novel molecular architectures for economically and environment friendly sustainable engineering applications.
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