Comparing Strategies for the Synthesis of Polyolefinic Thermoplastic Elastomers via Macromonomer Incorporation

Abstract

Abstract The microstructure of polyolefinic thermoplastic elastomers made with a combination of two single‐site catalysts was analyzed by Monte Carlo simulation. The model can be used to describe the crystallizable fraction for both long‐chain branched polypropylene ( a PP‐ g ‐ i PP) and long‐chain branched ethylene/ α ‐olefin copolymers (PE α O‐ g ‐PE). The simulations showed that at levels of 7.5% of comonomer incorporation, PE α O‐ g ‐PE samples reach a similar crystallizability level of a PP‐ g ‐ i PP. From a topological point of view, it was demonstrated that the fraction of free arms and inner segments tend to the limit of ½ for highly branched chains and that the fraction of free arms reaches its maximum value when the Y‐type chains are the predominant population. A mathematical correlation between the linear‐ and LCB catalyst probabilities was proposed to ensure the production of symmetrical branched chains. Long‐chain branch architecture of PE α O‐ g ‐PE. magnified image Long‐chain branch architecture of PE α O‐ g ‐PE.