Publications by authors named "Ricardo Mendoza Carrizales"

In this work, we explore the statistical copolymerization of 1,3-butadiene with the terpenic monomers myrcene and farnesene, carried out coordination polymerization using a neodymium-based ternary catalytic system. The resultant copolymers, poly(butadiene--myrcene) and poly(butadiene--farnesene), were synthesized at different monomer ratios, elucidating the influence of the bio-based monomer content over the kinetic variables, molecular and thermal properties, and the reactivity constants (Fineman-Ross and Kelen-Tüdös methods) of the resultant copolymers. The results indicate that through the herein employed conditions, it is possible to obtain "more sustainable" high- (≈95%) polybutadiene elastomers with random and tunable content of bio-based monomer.

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Towards the development of eco-friendly alternatives of elastomeric materials, which can replace petroleum-based materials, it is crucial to explore different monomers and catalytic systems in order to find the best possible combinations for specific applications. Herein, we report the synthesis of polyocimene coordination polymerization using two different neodymium-based catalysts (NdV and Nd(Oi-Pr)), activated by alkylaluminums/organoboron compounds. By varying the type of co-catalyst species, halide donors, and reaction parameters, we have demonstrated the possibility to obtain polymers with a controlled microstructure and tunable properties, in terms of molecular weight characteristics and kinetics.

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This article proposes a method to produce bio-elastomer nanocomposites, based on polyfarnesene or polymyrcene, reinforced with surface-modified graphene oxide (GO). The surface modification is performed by grafting alkylamines (octyl-, dodecyl-, and hexadecylamine) onto the surface of GO. The successful grafting was confirmed spectroscopic (FTIR and Raman) and X-ray diffraction techniques.

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Butyl rubber (isobutylene⁻isoprene⁻rubber, IIR) was functionalized in solution with a nitroxide moiety taking advantage of the unsaturations present in the isoprene units of IIR, and was further grafted with maleic anhydride (MA) or styrene⁻MA (SMA) to produce IIR--MA and IIR--SMA. In one of the functionalization techniques used, the molecular structure of the IIR was preserved as the chain-breaking reactions are prevented from occurring. The resulting graft copolymers were tested as compatiblizers/impact modifiers blended with Nylon-6, and one of them was preliminarily tested as a coupling agent in the preparation of nanocomposites of IIR and an organo-clay.

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