Francisco Javier Enríquez-Medrano

Dr. Francisco Javier Enríquez-Medrano

orcid
Researcher at CIQA, Mexico

Research Focus & Metrics

Academic Career Length

20Years (2007-Present)

(Calculated once Scilit publication data is synced: current year − year of first publication + 1)

Representative Publications

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19 September 2022 in Polymers
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MMManuel Eduardo Martínez-Cartagena
Manuel Eduardo Martínez-Cartagena
JBJuan Bernal-Martínez
Juan Bernal-Martínez
ABArnulfo Banda-Villanueva
Arnulfo Banda-Villanueva
Francisco Javier Enríquez-MedranoFrancisco Javier Enríquez-Medrano
Francisco Javier Enríquez-Medrano
VLVíctor D. Lechuga-Islas
Víctor D. Lechuga-Islas
Ramón Díaz de LeónRamón Díaz de León
Ramón Díaz de León
Polyaniline (PANI) composites have gained momentum as supercapacitive materials due to their high energy density and power density. However, some drawbacks in their performance remain, such as the low stability after hundreds of charge-discharge cycles and limitations in the synthesis scalability. Herein, we report for the first time PANI-Graphitic oxidized carbon nitride composites as potential supercapacitor material. The biomimetic polymerization of aniline assisted by hematin, supported by phosphorous and oxygen-modified carbon nitrides (g-POCN and g-OCN, respectively), achieved up to 89% yield. The obtained PAI/g-POCN and PANI/g-OCN show enhanced electrochemical properties, such as conductivity of up to 0.0375 S/cm, specific capacitances (Cs) of up to 294 F/g (at high current densities, 5 A/g) and a stable operation after 500 charge-discharge cycles (at 3 A/g). In contrast, the biomimetic synthesis of Free PANI, assisted by stabilized hematin in cosolvents, exhibited lower performance properties (65%). Due to their structural differences, the electrochemical properties of Free PANI (conductivity of 0.0045 S/cm and Cs of up to 82 F/g at 5 A/g) were lower than those of nanostructured PANI/g-POCN and g-OCN supports, which provide stability and improve the properties of biomimetically synthesized PANI. This work reveals the biomimetic synthesis of PANI, assisted by hematin supported by modified carbon nitrides, as a promising strategy to produce nanostructured supercapacitors with high performance.

7 September 2010 in Journal of Applied Polymer Science
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Francisco Javier Enríquez-MedranoFrancisco Javier Enríquez-Medrano
Francisco Javier Enríquez-Medrano
RGRamiro Guerrero-Santos
Ramiro Guerrero-Santos
MHMartín Hernández‐Valdez
Martín Hernández‐Valdez
PLPatrick Lacroix-Desmazes
Patrick Lacroix-Desmazes

21 August 2021 in Polymers
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IMIlse Magaña
Ilse Magaña
DGDimitrios Georgouvelas
Dimitrios Georgouvelas
RHRishab Handa
Rishab Handa
MVMaría Guadalupe Neira Velázquez
María Guadalupe Neira Velázquez
HGHECTOR RICARDO LOPEZ GONZALEZ
HECTOR RICARDO LOPEZ GONZALEZ
LVLuis Valencia
Luis Valencia
This article proposes a process to prepare fully bio-based elastomer nanocomposites based on polyfarnesene and cellulose nanocrystals (CNC). To improve the compatibility of cellulose with the hydrophobic matrix of polyfarnesene, the surface of CNC was modified via plasma-induced polymerization, at different powers of the plasma generator, using a trans-β-farnesene monomer in the plasma reactor. The characteristic features of plasma surface-modified CNC have been corroborated by spectroscopic (XPS) and microscopic (AFM) analyses. Moreover, the cellulose nanocrystals modified at 150 W have been selected to reinforce polyfarnesene-based nanocomposites, synthesized via an in-situ coordination polymerization using a neodymium-based catalytic system. The effect of the different loading content of nanocrystals on the polymerization behavior, as well as on the rheological aspects, was evaluated. The increase in the storage modulus with the incorporation of superficially modified nanocrystals was demonstrated by rheological measurements and these materials exhibited better properties than those containing pristine cellulose nanocrystals. Moreover, we elucidate that the viscoelastic moduli of the elastomer nanocomposites are aligned with power–law model systems with characteristic relaxation time scales similar to commercial nanocomposites, also implying tunable mechanical properties. In this foreground, our findings have important implications in the development of fully bio-based nanocomposites in close competition with the commercial stock, thereby producing alternatives in favor of sustainable materials.

17 July 2022 in Polymers
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TCTeresa Cordova
Teresa Cordova
Francisco Javier Enríquez-MedranoFrancisco Javier Enríquez-Medrano
Francisco Javier Enríquez-Medrano
ECEduardo Martínez Cartagena
Eduardo Martínez Cartagena
ABArnulfo Banda
Arnulfo Banda
LVLuis Valencia
Luis Valencia
Ramón Díaz de LeónRamón Díaz de León
Ramón Díaz de León
The present investigation involves the coordinative chain transfer polymerization (CCTP) of biobased terpenes in order to obtain sustainable polymers from myrcene (My) and farnesene (Fa), using the ternary Ziegler–Natta catalyst system comprising [NdV3]/[Al(i-Bu)2H]/[Me2SiCl2] and Al(i-Bu)2H, which acts as cocatalyst and chain transfer agent (CTA). The polymers were produced with a yield above 85% according to the monomeric consumption at the end of the reaction, and the kinetic examination revealed that the catalyst system proceeded with a reversible chain transfer mechanism in the presence of 15–30 equiv. of CTA. The resulting polyterpenes showed narrow molecular weight distributions (Mw/Mn = 1.4–2.5) and a high percent of 1,4-cis microstructure in the presence of 1 equiv. of Me2SiCl2, having control of the molecular weight distribution in Ziegler–Natta catalytic systems that maintain a high generation of 1,4-cis microstructure.

12 July 2021 in Molecules
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SHSaúl Luna Hernández
Saúl Luna Hernández
IBIsrael Bonilla-Landa
Israel Bonilla-Landa
ARAlfonso Reyes-Luna
Alfonso Reyes-Luna
ARAlfredo Rodríguez-Hernández
Alfredo Rodríguez-Hernández
UCUlises Cuapio-Muñoz
Ulises Cuapio-Muñoz
JOJosé Luis Olivares-Romero
José Luis Olivares-Romero
Xyleborus sp beetles are types of ambrosia beetles invasive to the United States and recently also to Mexico. The beetle can carry a fungus responsible for the Laurel Wilt, a vascular lethal disease that can host over 300 tree species, including redbay and avocado. This problem has a great economic and environmental impact. Indeed, synthetic chemists have recently attempted to develop new neonicotinoids. This is also due to severe drug resistance to “classic” insecticides. In this research, a series of neonicotinoids analogs were synthesized, characterized, and evaluated against Xyleborus sp. Most of the target compounds showed good to excellent insecticidal activity. Generally, the cyclic compounds also showed better activity in comparison with open-chain compounds. Compounds R-13, 23, S-29, and 43 showed a mortality percent of up to 73% after 12 h of exposure. These results highlight the enantioenriched compounds with absolute R configuration. The docking results correlated with experimental data which showed both cation-π interactions in relation to the aromatic ring and hydrogen bonds between the search cavity 3C79 and the novel molecules. The results suggest that these sorts of interactions are responsible for high insecticidal activity.

15 January 2021 in Processes
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LVLuis Valencia
Luis Valencia
Francisco Javier Enríquez-MedranoFrancisco Javier Enríquez-Medrano
Francisco Javier Enríquez-Medrano
HGHECTOR RICARDO LOPEZ GONZALEZ
HECTOR RICARDO LOPEZ GONZALEZ
Maria Quiñonez AnguloMaria Quiñonez Angulo
Maria Quiñonez Angulo
ESEnrique Saldívar-Guerra
Enrique Saldívar-Guerra
Ramón Díaz de LeónRamón Díaz de León
Ramón Díaz de León
Forty years after the discovery of metallocene catalysts, there are still several aspects that remain unresolved, especially when the “conventional” alkylaluminum activators are not used. Herein, we systematically investigated the synthesis of polyethylene (PE) via three different zirconocene catalysts, with different alkyl substituents, activated via different organoboron compounds. The polymerization behavior, as well as the properties of the materials, were evaluated. The results demonstrate that the highest catalytic activity is shown by bis(cyclopentadienyl)dimethylzirconium activated by trityl tetra(pentafluorophenyl)borate. Additionally, it was found that toluene is the optimum solvent for these systems and at these reaction conditions. Moreover, to validate our experimental results, a comprehensive mathematical model was developed on the basis of thermodynamic and kinetic principles. The concentration of ethylene transferred to the solvent phase (toluene) in a liquid–vapor equilibrium (LVE) system was estimated based on Duhem’s theorem. Arrhenius expressions for the kinetic rate constants of a proposed kinetic mechanism were estimated by a kinetic model, in which the rate of polymerization was fitted by a least-square optimization procedure and the molecular weight averages by the method of moments. The simulations of the coordination polymerization suggest the presence of two types of active sites, principally at low temperatures, and the reactivation of the deactivated sites via a boron-based activator. However, the effect of the temperature on the reactivation step was not clear; a deeper understanding via designed experiments is required.