Browsing by Author "TAGLE, LH"

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    POLY(TETRAHALO-P-PHENYLENESELENIDE)S - NEW SEMICONDUCTING POLYMERS
    (1989) DIAZ, FR; TAGLE, LH; GARGALLO, L; RADIC, D; GODOY, A
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    POLYAMIDE-IMIDES FROM 3',4'-DICARBOXY-4''-CHLOROFORMYL TEREPHTHALOYLPHENONE ANHYDRIDE
    (1975) TAGLE, LH; NEIRA, JF; DIAZ, FR; RAMIREZ, RS
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    POLYMERIZATION BY PHASE-TRANSFER CATALYSIS .1. POLYETHERS SYNTHESIS
    (1984) TAGLE, LH; DIAZ, FR; MUNOZ, AM
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    POLYMERIZATIONS BY PHASE-TRANSFER CATALYSTS .19. SYNTHESIS AND CHARACTERIZATION OF POLY(ESTERTHIOCARBONATE)S AND POLY(ESTERTHIOCARBONATE)S
    (SOCIEDAD CHILENA DE QUIMICA, 1994) TAGLE, LH; DIAZ, FR; CISTERNAS, H
    In this work we describe the synthesis of poly(estercarbonates) and poly(esterthiocarbonates) derived from the monomers 4-hydroxyphenyl-3-hydroxybenzoate (I) and 3-hydroxyphenyl-3-hydroxybenzoate (II) and phosgene and thiophosgene respectively. Polymers were synthesized under phase transfer catalysis conditions and using several ammonium salts as catalysts and dichloromethane as solvent. For polymers derived from 4-hydroxyphenyl-3-hydroxybenzoate (I) the more effective catalyst was TEBAC due to the hydrophilic character, being the other catalysts ineffective. For polymers derived from 3-hydroxyphenyl-3-hydroxybenzoate (II) catalysts showed no influence, and the phase transfer process is only due to an increase of the yields. All polymers were insoluble in the reaction media, which limited their growth.
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    SYNTHESES, CHARACTERIZATION AND ELECTRICAL-PROPERTIES OF SEVERAL POLY(SELENO-P-ARYLENEDIAMINES)
    (1995) DIAZ, FR; TAGLE, LH; GODOY, A; CONTRERAS, S
    Polymers derived from aromatic diamines and containing selenium between the two nitrogen atoms were synthesized and characterized. The electrical conductivities were measured before and after doping with I-2, SbF5, AlCl3 and FeCl3, showing semiconducting properties when doped with I-2 and SbF5.
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    SYNTHESIS AND CHARACTERIZATION OF COPOLYMERS FROM ACRYLIC AND METHACRYLIC-ACID WITH 2-METHYLAZIRIDINE BY SPONTANEOUS COPOLYMERIZATION
    (1995) RIVAS, BL; PIZARRO, GD; TAGLE, LH; RADIC, D
    2-Methylaziridine (MAz) as a nucleophilic monomer and acrylic acid (AA) and methacrylic acid (MA), respectively, as electrophilic monomers were copolymerized in the absence of initiator at various feed ratios. Copolymers were characterized by elemental analysis, FT-IR and H-1-NMR spectroscopy. The monomer reactivity ratios were determined by the Fineman-Ross and Kelen-Tudos methods. Values of r(1) and r(2) were found to be less than unity for MAz-AA, and MAz-MA, corresponding to random copolymers with the tendency to the alternance. For all the copolymers the thermal decomposition with 10% weight loss is higher than 430 K. The reaction order for degradation of all copolymers was zero. The kinetic parameters of the decomposition were determined for all copolymers.
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    SYNTHESIS AND CHARACTERIZATION OF LIQUID-CRYSTAL POLYMERS WITH OLIGOSILOXANE SPACERS
    (1993) DIAZ, F; TAGLE, LH; VALDEBENITO, N; AGUILERA, C
    Diesters from 4-vinylbenzoic acid and biphenols with structural mesogenic characteristics were synthesized and interconnected by siloxane spacers with different lengths. Polymers were characterized by i.r., H-1 n.m.r. and elemental analysis. Thermal properties were studied by d.s.c. and polarized light microscopy.
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    THERMAL STUDIES OF METAL POLY(BUTYL METHACRYLATES) .13.
    (GORDON BREACH SCI PUBL LTD, 1994) CARDENAS, G; SALGADO, E; TAGLE, LH
    Metal poly(butyl methacrylates) polymers were obtained by radical polymerization with benzoyl peroxide. The monomer was cocondensed with the metals: Cu, Ag, Au, Pd, Zn, Cd, Ga, In, Ge, Sn, Sb and Bi. The metals were evaporated to produce atoms and with the monomer they can generate a matrix at 77 K. After the warm up process, metal-monomer colloids can be obtained. The colloids were polymerized with benzoyl peroxide at 70 degrees C for 0.5 h at 70 degrees C. Four different initiator concentrations (0.5, 1.0, 1.25 and 5.0 mol%) were used. The yields are over 50% and the viscosimetric molecular weight range from 10(4)-10(5) g/mol. The higher My are Sb, In, Ag and Ge-poly(butyl methacrylates). The thermal stabilities of these metal polymers have been studied by thermogravimetry (TG) between 25 and 550 degrees C under nitrogen flow. The decomposition temperature was obtained from the maximum of the first derivative from TG curve. The kinetic parameters of the thermal decomposition were determined by the Arrhenius equation. All these polymers degrade in a single step around 300 degrees C. The kinetic data thus obtained show the thermostabilities decrease in the order: Pd-PBMA > Au-PBMA > In-PBMA > Sn-PBMA > Ag-PBMA > Sb-PBMA > Bi-PBMA > Ge-PBMA > Zn-PBMA > Ga-PBMA > Cu-PRMA > Cd-PBMA. The thermal stability apparently is depending upon the metal incorporated in the polymer matrix. The decomposition reaction order is -0.25 or -0.5 which means that we are in the presence of a complex single decomposition reaction, The pre-exponential factor, the activation energy, the reaction order and the decomposition temperature for all the polymers have been determined.
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    THERMAL STUDIES OF METAL POLY(N-BUTYL METHACRYLATES) .10.
    (1993) CARDENAS, G; SALGADO, E; TAGLE, LH
    Metal poly(n-butylmethacrylates) polymers were obtained by radical polymerization with azodiisobutyronitrile (AIBN). The thermal stabilities of the metal polymers (M-PBMA) have been studied by thermogravimetry (TG) between 25 and 550-degrees-C under nitrogen flow. The decomposition temperature was obtained from the first derivative of the TG curve. The kinetic parameters of the thermal decomposition were determined by the Arrhenius equation. All these polymers degrade in a single step. The kinetic data thus obtained show that the thermostabilities decrease in the order Pd-PBMA > Ga-PBMA > Cu-PBMA > Ag-PBMA > Au-PBMA > Al-PBMA > Cd-PBMA > Ge-PBMA > Zn-PBMA > Sb-PBMA > In-PBMA > Sn-PBMA. In fact, the thermal stability is dependent upon the metal incorporated in the polymer, the highest being stable up to 389-degrees-C and the lowest up to 260-degrees-C. The order of reaction from the thermal decomposition of these metal polymers was found to be -0.25 for the homopolymers, Pd, Au, Ag, Cd, Zn, Ga, Ge and Sn but -0.5 for Bi, Sb and Al. The pre-exponential factor, the reaction order and the activation energy of the decomposition reaction for M-PBMA have been determined.
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    THERMAL STUDIES OF METAL POLY(STYRENE-CO-ACRYLONITRILE) .14.
    (TAYLOR & FRANCIS AS, 1994) CARDENAS, G; ACUNA, J; CARBACHO, H; RODRIGUEZ, M; TAGLE, LH
    The thermal stabilities of metal poly(styrene-co-acrylonitrile) has been studied by thermogravimetry (TG) between 278 K and 823 K under nitrogen flow. The kinetic data thus obtained indicate that the thermostabilities decrease in the order: Sn-STAN > Ga-STAN > Ag-STAN > Sb-STAN > Cu-STAN > Pd-STAN > Fe-STAN > Au-STAN > Bi-STAN for high Molecular Weight (HMW) and Ag-STAN > Pd-STAN > Fe-STAN > Ga-STAN > Cu-STAN > Sb-STAN > Sn-STAN > Bi-STAN > Au-STAN for low Molecular Weight (LMW) copolymers. The thermal stability seems to be dependable on the nature of the bond established between the copolymer and the metal. Cu-copolymer exhibits the lowest Ea most probably due to their oxidation potential. On the other hand, Ag-copolymer has the highest Ea and similar to the copolymer (fraction 1). The thermal decomposition temperatures were obtained from the DTG curves. The reaction order for the thermal decomposition of these copolymers is zero. In other words, we are dealing with a single step decomposition mechanism. The pre-exponential factor, the reaction order, the decomposition temperature and the activation energy of the decomposition for metal poly(styrene-co-acrylonitrile) have been determined.
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    THERMAL STUDIES OF METAL POLY(VINYL ACETATES) .9.
    (1995) CARDENAS, G; MUNOZ, C; TAGLE, LH
    Metal poly(vinyl acetates) polymers were obtained by radical polymerization with azodiisobutyronitrile. The thermal stabilities of the metal polymers (M-PVAC) have been studied by thermogravimetry (TG) between 25 and 550-degrees-C under nitrogen flow. The decomposition temperature was obtained from the maximum of the first derivative from TG curve. The kinetic parameters of the thermal decomposition were determined by the Arrhenius equation. All these polymers degrade mainly in a single step with a very small second step, probably via a complex reaction. The kinetic data thus obtained show that the thermostabilities decrease in the order: Sb-PVA(c) approximately Ge-PVA(c) > Bi-PVA(c) approximately Cd-PCA(c) > Ag-PVA(c) approximately PVA(c) > Zn-PVA(c) > Au-PVA(c) > In-PVA(c) > Sn-PVA(c) > Ga-PVA(c) > Pd-PVA(c).
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    THERMAL STUDIES OF METAL POLYSTYRENES .4.
    (1992) CARDENAS, G; RETAMAL, C; TAGLE, LH
    The thermal stability of metal polystyrene was determined by thermogravimetric analyses (TGA) from 25 to 250-degrees-C under nitrogen flow.
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    THERMAL STUDIES OF METAL-FILMS PREPARED WITH OXYGENATED SOLVENTS .12.
    (1994) CARDENAS, G; OLIVA, R; TAGLE, LH
    Copper, silver and gold colloids have been prepared by Chemical Liquid Deposition (CLD) with dimethoxymethane, 2-methoxyethyl ether and ethylenglycol dimethyl ether. The metals are evaporated to yield atoms which are solvated at low temperatures and during the warm up process colloidal sols with metal clusters are obtained.
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    THERMAL STUDIES OF ORGANOZINC FILMS .11.
    (1994) CARDENAS, G; OLIVA, R; TAGLE, LH
    The thermal stability of organozinc films was studied by thermogravimetric analysis (TGA) between 25 and 550-degrees-C min-1. The decomposition temperatures were obtained from the maximum of the first derivatives of the TG curve. The kinetic parameters of the thermal decomposition were determined by the Arrhenius equation. All the films degraded in one step with a very small weight loss. Films prepared with toluene and THF exhibit higher weight losses, 23.77% and 12.48%, respectively, and zinc-2-propanol film is the most stable (1.11% weight loss).
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    THERMAL-ANALYSIS OF METAL POLYACRYLONITRILES
    (1991) CARDENAS, G; RETAMAL, C; TAGLE, LH
    The thermal stabilities of metal polyacrylonitriles (MPAN) were studied by thermogravimetric analysis (TGA) between 25 and 550-degrees-C under nitrogen flowing at 10-degrees-C min-1. The metal contents of the polymers and their molecular weights are also reported. The kinetic data obtained by TGA showed that the thermostabilities of these polymers decrease in the order: Ge-PAN > Ga-PAN > Au-PAN > Sn-PAN > Bi-PAN > In-PAN > Pd-PAN > Sb-PAN. The experimental data suggest that the thermal stability of these polymers depends on the metal and the amount of metal incorporated. The reaction order for the one-step thermal decomposition of the polymers was found to be zero. The pre-exponential factor, the reaction order and the activation energies for the decomposition of the metal polyacrylonitriles were determined.
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    THERMAL-DEGRADATION AND DETERMINATION OF KINETIC-PARAMETERS BY DYNAMIC THERMOGRAVIMETRY OF COPOLYMERS SYNTHESIZED WITHOUT INITIATOR
    (1991) RIVAS, BL; PIZARRO, GD; CATALAN, RE; TAGLE, LH
    The thermal degradation of a series of 18 copolymers of 2-methylaziridine and 1-(2-hydroxyethyl)aziridine with N-phenylmaleimide and derivatives obtained without added catalyst, was investigated using thermogravimetry (TGA) under a dynamic nitrogen atmosphere over a temperature range from 20 to 500-degrees-C. Almost all the copolymers degrade in one step. The kinetic parameters E(a), n and A were obtained following one method of thermogravimetric analysis. The thermal stability depends on the copolymer composition which was determined from the H-1 NMR spectra. The most stable material was poly(p-nitrophenylmaleimide-co-2-methylaziridine).