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Your search keyword '"Santiago-García, José Luis"' showing total 19 results
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19 results on '"Santiago-García, José Luis"'

11. Sulfonated aromatic copoly(ether–amide) membranes II

Author

Sosa-González, Wadi Elim, primary, Palí-Casanova, Ramón del Jesús, additional, Pérez-Padilla, Yamile, additional, Loría-Bastarrachea, María Isabel, additional, Santiago-García, José Luis, additional, and Aguilar-Vega, Manuel de Jesús, additional

Published
2017
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13. Preparation and Characterization of Flexible, Transparent and Thermally Stable Aromatic Co-polyamides.

Author

Tec-Sánchez, José Antonio, Arias, Andrés Iván Oliva, Aguilar-Vega, Manuel, Cauich-Rodríguez, Juan Valerio, and Santiago-García, José Luis

Subjects
ARAMID fibers, POLYCONDENSATION, THERMAL stability, POLYAMIDE membranes, SUBSTITUENTS (Chemistry)
Abstract

Two aromatic co-polyamides were synthesized combining two diacid monomers containing bulky pendant groups, 5-(9,10-dihydro-9,10-ethanoanthracene-11,12-dicarboximido)isophthalic acid (DEAIA) and 5-tert-butylisophthalic acid (TERT), with 4,4′-(hexafluoroisopropylidene)dianiline (HFA) or 2,3,5,6-tetramethyl-1,4-phenylenediamine (Durene) by direct polycondensation. The structures of the obtained aromatic co-polyamides were confirmed by FTIR, Raman and 1H-NMR. The co-copolyamide films, DHTH and DDTD, exhibited rms-roughness values between 0.94 and 1.60 nm, respectively. Moreover, they presented good thermal stability up to 300 °C. Young's moduli of the co-polyamide films were between 4.1 and 4.3 GPa. X-ray diffraction results showed that the co-polyamide films were amorphous due to the incorporation of both bulky pendant groups, tert-butyl and dibenzobarrelene. The combination of bulky pendant groups provided intrinsically transparent co-polyamide films with a transmittance higher than 88% in the range of 400−780 nm. Due to these outstanding film and optical properties, they are suggested to be flexible substrates in applications for solar cell and other portable electronic devices. [ABSTRACT FROM AUTHOR]

Published
2019
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14. Evaluation of Gas Transport Properties of Highly Rigid Aromatic PI DPPD-IMM/PBI Blends

Author

Pérez-Francisco, José Manuel, Santiago-García, José Luis, Loría-Bastarrachea, María Isabel, and Aguilar-Vega, Manuel

Abstract

In this work we discuss the gas transport properties behavior of dense blend membranes of a high free volume polyimide PI DPPD-IMM with PBI using the latter polymer in an attempt to enhance gas selectivity. Thermal and mechanical properties of dense blend membranes were also evaluated. The aim is to test the use of PBI as a gate polymer for establishing a window to enhance selectivity of CO2/CH4and O2/N2gas pairs with a minimum loss of gas permeability. Wide-angle X-ray diffraction measurements show that PI DPPD-IMM has an open structure with a d-spacing maximum at 5.4 Å, which is not affected when PBI concentration in the blends is lower than 25 wt %. This reflects a moderate loss of gas permeability as compared to PI DPPD-IMM. Blends with PBI concentrations 50 wt % or above presented a shift in WAXD toward 4.4 Å. It is found that as PBI concentration increases in the blend, there is an enhanced selectivity for O2/N2and CO2/CH4gas pairs duplicating their value with respect to PI DPPD-IMM and following closely the slope of the Robeson plot. Activation energies for permeation confirm that the PI DPPD-IMM microstructure is preserved at low PBI concentration since they barely increase for blends containing <25 wt % PBI. Gas permeability coefficients were fitted to different prediction models whose analysis confirms that the blends are heterogeneous. The best relationship between gas permeability and gas pair selectivity is located in the region where the blend presents high fractional free volume (FFV) (PBI concentration ≤25 wt %).

Published
2024
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15. Gas transport properties of new aromatic polyimides based on 3,8-diphenylpyrene-1,2,6,7-tetracarboxylic dianhydride

Author

Santiago-García, José Luis, Álvarez, Cristina, Sánchez, Félix, Campa, José G. de la, Santiago-García, José Luis, Álvarez, Cristina, Sánchez, Félix, and Campa, José G. de la

Abstract

Three novel polyimides have been successfully synthesized from 3,8-diphenylpyrene-1,2,6,7-tetracarboxylic dianhydride (DPPD), and three commercial diamines by solution polycondensation. All polymers exhibited high molecular weight, high thermal stability and high rigidity (no glass transition was detected up to 400°C) and free volume. The new polymers have been tested as gas separation membranes, showing very good combination of permeability and selectivity, especially in the case of the polymer derived from trimethyl-m-phenylenediamine (TMPD), which overpassed the 1991 Robeson upper bound for the gas pairs O2/N2 and CO2/CH4 and was near the 2008 upper bound for CO2/N2.

Published
2015

16. Assessment of random aromatic co-polyamides containing two different bulky pendant groups.

Author

Pérez‐Francisco, José Manuel, Herrera‐Kao, Wilbert, González‐Díaz, María Ortencia, Aguilar‐Vega, Manuel, and Santiago‐García, José Luis

Subjects
COPOLYMERS, AROMATIC compounds, CHEMICAL synthesis, POLYCONDENSATION, VISCOSITY, PERMEABILITY
Abstract

ABSTRACT This work reports the synthesis and assessment of random aromatic co-polyamides containing two different bulky pendant groups. The random aromatic co-polyamides are synthesized combining the monomers 5- tert-butylisophthalic acid and 5-(9,10-dihydro-9,10-ethanoanthracene-11,12-dicarboximido)isophthalic acid with three different diamines. The random aromatic co-polyamides are readily soluble and possess inherent viscosities in the range of 0.47-0.60 dL g−1. Co-polyamide dense membranes are amorphous, and flexible with both good tensile strength (56.2-57.5 MPa) and tensile modulus (1.3-1.6 GPa). Permeability coefficients of the co-polyamide dense membranes are assessed for the gases He, O2, N2, CH4, and CO2. It is found that the combination of two bulky pendant groups, dibenzobarrelene and tert-butyl, in the backbone of the co-polyamides improves the gas permeability coefficient in comparison with their corresponding homopolyamides. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018, 135, 45884. [ABSTRACT FROM AUTHOR]

Published
2018
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