Browsing by Author "Tagle, Luis H."

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    A new porous organic polymer containing Troger's base units: Evaluation of the catalytic activity in Knoevenagel condensation reaction
    (2021) Rodriguez-Gonzalez, Fidel E.; Niebla, Vladimir; Velazquez-Tundidor, M. V.; Tagle, Luis H.; Martin-Trasanco, Rudy; Coll, Deysma; Ortiz, Pablo A.; Escalona, Nestor; Perez, Edwin; Jessop, Ignacio A.; Terraza, Claudio A.; Tundidor-Camba, Alain
    The classic Tro center dot ger's base polymerization of a diamine and dimethoxymethane with trifluoroacetic acid as catalyst generated a Tro center dot ger's base-type polymer (TBP), which exhibited the absolute insolubility in a variety of organic solvents because of its highly aggregated model. A new porous organic polymer was obtained by a simple Tro center dot ger's base polymerization reaction between a diamine and formaldehyde in the form of acetal in the presence of trifluoroacetic acid as catalyst. Tro center dot ger's base-type polymer (TBP) resulted insoluble in a wide range of organic solvents due to its rigid and aromatic structure. TBP was characterized spectroscopically (FT-IR), thermally and morphologically. As result, a thermostable and amorphous polymer bearing pores ranging between 50 and 300 nm and macro-voids of up to 12 mu m was obtained. Due to the insolubility of the TBP, it was tested as a metal-free heterogeneous catalyst in the Knoevenagel condensation reaction, showing a high efficiency. For this, the optimal catalyst load, reaction time and reuse of the catalyst were studied using benzaldehyde and malononitrile as substrates. Furthermore, aldehydes with variable chain sizes and ethyl cyanoacetate replacing malononitrile were tested as substrate with a high percent of conversion (97-99%).
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    Synthesis and Properties of Poly(imides) and Poly(imides)/Ionic Liquid Composites Bearing a Benzimidazole Moiety
    (2019) Terraza, Claudio A.; Ortiz, Pablo; Tagle, Luis H.; Perez, German; Saldias, Cesar; Rodriguez-Gonzalez, Fidel E.; Cabrera-Barjas, Gustavo; Catalan, Henry; Tundidor-Camba, Alain; Coll, Deysma
    Three new aromatic poly(imides) containing benzimidazole units in the backbone were synthesized and characterized by several spectroscopic techniques. Flexible spacer groups were incorporated into the poly(imides) structure to improve their solubility in organic solvents and their oxidative stabilization. All poly(imides) were thermally stable (T-d5% > 512 degrees C) and had the ability to form dense flexible films. Novel composite films were successfully prepared by loading poly(imide) with ionic liquid ([Bmim]Br) at different concentrations up to 25 wt.%. The resulting materials were characterized according to their morphology and elemental composition (SEM-EDX), water uptake capability, contact angle, and oxidative degradation resistance. Results suggested that poly(imide)/ionic liquid composites would be excellent candidates for future proton conductivity measurements.
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    SYNTHESIS, CHARACTERIZATION AND FILM PREPARATION OF NEW CO-POLYIMIDE BASED ON NEW 3,5-DIAMINO-N-(PYRIDIN-4-YLMETHYL)BENZAMIDE, ODA AND 6FDA
    (2018) Tundidor-Camba, Alain; Saldias, Cesar; Tagle, Luis H.; Terraza, Claudio A.; Coll, Deysma; Perez, German; Aguilar-Vega, Manuel; Abarca, Romina L.; Ortiz, Pablo A.
    This work describes mainly the synthesis and characterization of new co-polyimides obtained from the polycondensation of the dianhydride 4,4'-(hexafluoroisopropylidene)diphtlialic anhydride (6FDA), 4,4'-oxydianiline (ODA) and the new diamine 3,5-diamino-N-(pyridin-4-ylmethyl)benzamide (PyDA). It describes as the different compositions of ODA and PyDA present in the polymers. produce variation on thermal and mechanical properties, which are important characteristics for the development of future nanocomposites derived from these polymers. Both PyDA monomer and polymers were characterized using FT-IR and NMR (H-1, C-13, F-19, dept 135 degrees, COSY, HMBC, HMQC) spectroscopy. The inherent viscosity of polymers is between 0.3 to 1.49 dL/g, they are soluble in aprotic polar solvents, such as: DMSO, DMF and DMA. In addition, all co-polymers showed thermal decomposition temperature and glass transition temperatures above 483 degrees C and 289 degrees C, respectively. Mechanical tests under tension of co-polymer films showed Young's modulus between 2.1-3.9 GPa and tensile strength between 35.5 and 120.0 MPa. On the other hand, an increase in crystallinity and hydrophilicity is observed when increasing the amount of pyridinyl groups.
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    Tri-functional oligomeric polyesters prepared from new dicarboxylic acids containing several amino acids residues by Higashi methodology: synthesis, characterization, and study of solubility and thermal behavior
    (2021) Tundidor-Camba, Alain; Tagle, Luis H.; Terraza, Claudio A.; Rivera, Jorge; Coll, Deysma; Ortiz, Pablo A.
    The synthesis of polyfunctional aliphatic oligomeric polyesters (poly(ether-imido-esters;PEIEs) containing several amino acid residues is described, and their thermal properties and solubility behavior were studied. The new symmetrical monomeric dicarboxylic acids were synthesized using 4-nitrophthalonitrile as starting material, which reacted with bisphenol-A or bis(4-hydroxyphenyl)diphenylmethane. Then, the tetranitrile derivatives were hydrolyzed to the tetracarboxylic acids and dehydrated to the respective dianhydrides. Finally, these compounds reacted with the amino acids glycine orL-alanine to obtain the aliphatic dicarboxylic acid monomers.PEIEs were obtained by Higashi methodology from these monomers and bisphenol-A, characterized by elemental analysis, NMR and IR, and the results were in agreement with the structures. The materials were soluble at 25 degrees C in several aprotic polar organic solvents and some in CHCl(3)and THF. In agreement with the viscosity and SEC results,PEIEswere oligomers with degree of polymerization of four and six, and Mw and Mn between 7370-9790 g/mol and 3680-4850 g/mol, respectively. The samples showed lowT(g)values (124-160 degrees C), associated with important structural flexibility promotes by dicarboxylic acid monomers. Despite this, this parameter depended of the aminoacidic residue nature in the sense that when the volume of it increased, theT(g)also increased due to a decrease in the free rotation that negatively affects the segmental movements of the chains. This effect was also observed when the side groups of the diphenol moiety of the dicarboxylic acid monomers increase from methyl to phenyl. The recorded TDT(10%)values from the TGA analysis (334-457 degrees C) do not allow to consider these samples as thermoset materials. In this sense, it was possible to observe an average increase of 8-13 degrees C and 23-28 degrees C when the lateral group volume of the amino acid residues and of the diphenol moiety are increased, respectively.