"Chain walking” catalytic polymerization CWCP is a powerful tool for the one-pot synthesis of a unique class of hyperbranched polyethylene HBPE-based macromolecules with a controllable molecular weight, topology, and composition. This dissertation focuses on new synthetic routes to prepare HBPE-based macromolecular architectures by combining the CWCP technique with ring opening polymerization ROP, atom–transfer radical polymerization ATRP, and “click” chemistry. Taking advantage of end-functionalized HBPE, and a new ethynyl-soketal star-shape agent, we were able to synthesize different types of the HBPE-based architectures including hyperbranched-on-hyperbranched core-shell nanostructure, and miktoarm-star-HBPE-based block copolymers. The first part of the dissertation provides a general introduction to the synthesis of polyethylene types with controllable structures. Well-defined polyethylene with different macromolecule architectures were synthesized either for academic or industrial purposes. In the second part, the HBPE with different topologies was synthesized by CWCP, using a α-diimine Pd (II) catalyst. The effect of the temperature and pressure on the catalyst activity and polymer properties, including branch content, molecular weight, distribution, and thermal properties were studied. Two series of samples were synthesized: a) serial samples (A) under pressures of 1, 5, and 27 atm at 5˚C, and b) serial samples (B) at temperatures of 5, 15, and 35 ˚C under 5 atm. Proton nuclear magnetic resonance spectroscopy, 1H NMR, and gel permeation chromatography, GPC, analysis were used to calculate the branching content, molecular weight, and distribution, whereas differential scanning calorimetry, DSC, was used to record the melting and glass transition temperatures as well as the degree of the crystallinity. Well-defined HBPE-based core diblock copolymers with predictable amphiphilic properties are studied in the third part of the project. Hyperbranched polyethylene-b-poly(N-isopropylacrylamide), HBPE-b-PNIPAM, and hyperbranched polyethylene-b-poly(solketal acrylate), HBPE-b-PSA, were successfully synthesized by combining CWCP and ATRP. The synthetic methodology includes the following steps; a) synthesis of multifunction hyperbranched polyethylene initiators HBPE-MI by direct copolymerization of ethylene with 2-(2-bromoisobutyryloxy)ethyl acrylate BIEA in the presence of a α-diimine Pd(II) catalyst, and b) HBPE-MI with α-bromoester groups used as initiation sites for ATRP. Proton nuclear magnetic resonance spectroscopy, 1H NMR, gel permeation chromatography,GPC, and Fourier transform infrared, FT-IR, spectroscopy, were used for determining the molecular and composition structures. Also, differential scanning calorimetry, DSC, and thermogravimetric analysis, TGA, were used to record the melting temperature and to study the thermal stability, respectively. In the fourth part, a well-defined 3-miktoarm star copolymer 3μ-HBPE(PCL)2 (HBPE: hyperbranched polyethylene, PCL: poly(ε-caprolactone) was synthesized by combining CWCP, ring opening polymerization, ROP, and “click” chemistry. The synthetic methodology includes the following steps: a) synthesis of azido-functionalized hyperbranched polyethylene HBPE-N3 by CWCP of ethylene with the α-diimine Pd(II) catalyst, followed by quenching with an excess of 4-vinylbenzyl chloride and transformation of –Cl to the azido group with sodium azide, b) synthesis of in-chain ethynyl-functionalized poly(ε-caprolactone), (PCL)2-C≡CH by ROP of ε-CL with ethynylfunctionalized solketal [3-(prop-2-yn-1-yloxy) propane-1,2-diol] as a bifunctional initiator, in the presence of P2-t-Bu phosphazene super base, and c) “clicking” HBPE-N3 and (PCL)2-C≡CH using the copper(I)-catalyzed alkyne–azide cycloaddition CuAAC. Proton nuclear magnetic resonance spectroscopy, 1H NMR, gel permeation chromatography, GPC, and Fourier transform infrared, FT-IR, spectroscopy, were used to determine the molecular and composition structures. Also, the differential scanning calorimetry, DSC, was used to record the melting point temperature. The fifth part illustrates the self-assembly behavior of the HBPE-based block copolymers of poly(N-isopropylacrylamide), NIPAM, and poly(ε-caprolactone), PCL, at room temperature in water and a petroleum ether-selective solvent for NIPAM and PCL respectively. The synthesized copolymers HBPE-b-NIPAM and 3μ-HBPE(PCL)2 revealed either core-shell nanostructure in vesicles or worms and worm-likes branches, as confirmed by combining the analysis of dynamic light scattering, DLS, transmission electron microscopy, TEM, and atomic force spectroscopy, AFM. All the findings presented in this dissertation emphasize the utility of "living" CWCP to synthesize end-functionalized HBPE, and new star-linkage HBPE-based complex architectures. The summary and future works concerning predictable properties and applications are discussed in the sixth part.

This dissertation is dedicated to the complete structural elucidation of chain-walking polyethylene (CWPE) using state-of-the-art analytical technology, including light and neutron scattering experiments as well as advanced liquid chromatography. In doing so, the structural characteristics of CWPE shall be determined on global and segmental scale in order to clearly differentiate this material class from other classical types of PE. Moreover, it is aimed to clarify the true potential of CW catalysis including possibilities and limitations.

We were accomplished modeling employing chemical-computational tools in order to foreknow the influence of a chiral environment on the active center of catalytic diimina Brookhart-Guan modified systems proposed by our Group. These complexes are used to produce branched or linear chains of polyethylene, having ethene as the single monomer. In this study, a computational design of a cyclophane diiminie chiral ligand, Brookhart-Guan modified type, and its respective palladium complex have been attained. Also, a computational studied related to the microstructure of the polyethylene obtained have been achieve. For that, growing chains have been simulated bearing branches that must be correctly oriented due to the esteric and chiral (using the FTFT like ligand) environments present at the active center also, modeling for possibilities of transition state in the insertion step for desired complex. This work can lead to a suitable design of a catalyst, besides to forecast the structural characteristics of the polymers obtained from this type of catalytic system. At the same way, those simulations allow to understand the effect observed in those type of Pd-diimine catalytic complexes for ethane polymerization. / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / Neste trabalho foram realizadas modelagens empregando ferramentas químicocomputacionais, com o objetivo de prever a influência que um ambiente quiral em torno do centro de atividade de sistemas catalíticos Pd-diimínicos do tipo Brookhart-Guan modificados, proposto pelo nosso Grupo. Estes complexos catalíticos podem ser utilizados para a obtenção de cadeias lineares ou ramificadas de polietileno, tendo-se como único monômero o eteno. Neste estudo foi realizado o design computacional de um pré-ligante do tipo ciclofano diimínico quiral, do tipo Brookhart-Guan modificado, e de seu respectivo complexo de paládio. Além disso, foi realizado o estudo computacional relativo à microestrutura do polímero a ser obtido empregando eteno como único monômero. Para tanto, foram modeladas cadeias em crescimento apresentando ramificações que devem ser orientadas em função do ambiente estéreo e assimétrico (usando o ligante FTFT) em torno do centro catalítico, além de modelagens para os possíveis estados de transição na etapa de inserção para o complexo desejado. Este trabalho de poderá proporcionar o adequado design do catalisador, além de prever as características estruturais do polímero obtido com este sistema catalítico. Da mesma forma, as simulações permitem compreender os efeitos observados para catalisadores a base de Pd-diimina na polimerização do eteno.