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1.
Robert Andreu Gerard Lligadas Joan Carles Ronda Marina Galià Virginia Cádiz 《Journal of polymer science. Part A, Polymer chemistry》2007,45(21):4965-4973
A new oxazolidine derivative was obtained from phenol, 2‐amino‐2‐methylpropane‐1,3‐diol and paraformaldehyde. The reaction of this novel oxazolidine diol with phenylisocyanate lead to a urethane model compound which can be polymerized thermally by oxazolidine ring opening to give a Mannich bridge structure. Linear segmented polyurethanes were prepared by reaction of different ratios of oxazolidine diol and commercial polyethylenglycol (Mw ~ 400) with 4,4′‐methylenbis (cyclohexylisocyanate) (HMDI, 90% isomers mixture). The polyurethanes were thermally characterized and crosslinked by oxazolidine ring opening to obtain materials which showed improved thermal stability. © 2007 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 45: 4965–4973, 2007 相似文献
2.
V. Naveen Kumar P. Someshwar P. Narsimha Reddy Y. Thirupathi Reddy B. Rajitha 《Journal of heterocyclic chemistry》2005,42(5):1017-1019
The condensation reaction of aldehydes, β‐ketoesters and urea/thiourea in presence of a catalytic amount of CuPy2Cl2 complex proceeded under very mild reaction conditions in high yield (80‐90%). 相似文献
3.
Tegos GP Demidova TN Arcila-Lopez D Lee H Wharton T Gali H Hamblin MR 《Chemistry & biology》2005,12(10):1127-1135
Fullerenes are soccer ball-shaped molecules composed of carbon atoms, and, when derivatized with functional groups, they become soluble and can act as photosensitizers. Antimicrobial photodynamic therapy combines a nontoxic photosensitizer with harmless visible light to generate reactive oxygen species that kill microbial cells. We have compared the antimicrobial activity of six functionalized C(60) compounds with one, two, or three hydrophilic or cationic groups in combination with white light against gram-positive bacteria, gram-negative bacteria, and fungi. After a 10 min incubation, the bis- and tris-cationic fullerenes were highly active in killing all tested microbes (4-6 logs) under conditions in which mammalian cells were comparatively unharmed. These compounds performed significantly better than a widely used antimicrobial photosensitizer, toluidine blue O. The high selectivity and efficacy exhibited by these photosensitizers encourage further testing for antimicrobial applications. 相似文献
4.
5.
Reddy P. Malla Venugopal M. Rajitha G. 《Journal of Applied Mechanics and Technical Physics》2022,63(2):259-267
Journal of Applied Mechanics and Technical Physics - In this paper, SH-wave propagation in an initially stressed triclinic layer welded between two half-spaces is investigated. The upper half-space... 相似文献
6.
Nives Galić Nataša Burić Renato Tomaš Leo Frkanec Vladislav Tomišić 《Supramolecular chemistry》2013,25(5):389-397
The fluorescent peptidocalixarenes, 5,11,17,23-tetra-tert-butyl-25,26,27,28-tetrakis(O-methyl-l-tryptophanylcarbonylmethoxy)calix[4]arene (1) and 5,11,17,23-tetra-tert-butyl-25,27-di(O-methyl)-26,28-bis(O-methyl-l-tryptophanylcarbonylmethoxy)calix[4]arene (2), were prepared by introducing tryptophan subunits at a lower calixarene rim. Coordination abilities of 1 and 2 towards Eu(III) and alkali metal cations were studied by spectrophotometric, spectrofluorimetric, conductometric and potentiometric titrations in acetonitrile at 25°C. Rather strong complexation was observed for smaller alkali metal cations Li+ and Na+ (log K Li1 >6, log K Li2 >6, log K Na1 = 8.25, log K Na2 = 6.94), and moderate for K+ (log K K1 = 5.09, log K K2 = 4.09). Larger Rb+ and Cs+ cations did not fit in the ion binding site of 1 so no complexation was detected, whereas the more flexible ligand 2 accommodated Rb+ cation (log K Rb2 = 3.44). The fluorescence of 1 (λex = 280 nm, λem = 340 nm) was remarkably quenched by Eu(III). Stability constant of 1:1 (Eu3+:1) complex determined spectrofluorimetrically amounted to log K Eu1 = 6.16. 相似文献
7.
Gerard Lligadas Juan C. Ronda Marina Galià Virginia Cádiz 《Journal of polymer science. Part A, Polymer chemistry》2013,51(10):2111-2124
As a consequence of the depleting of fossil reserves and environmental issues, today, plant oils and fatty acids derived therefrom have a respectable status within the polymer chemistry community. However, maximizing the benefits of these renewable feedstocks requires the utilization of sustainable and efficient chemical transformations. The emergence of click chemistry concept and especially the renaissance of thiol‐ene addition reaction have had an impact on the way to make plant oil‐derived polymers. This highlight discusses the applicability and success of thiol‐ene addition and other click reactions in the transformation of oleochemicals into monomers and polymers. © 2013 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2013 相似文献
8.
C. Zúñiga M. S. Larrechi G. Lligadas J. C. Ronda M. Galià V. Cádiz 《Journal of polymer science. Part A, Polymer chemistry》2011,49(5):1219-1227
The novel benzoxazine monomers, DPA‐Bz and MDP‐Bz from renewable diphenolic acid (DPA), which mimics the structure of bisphenol A (BPA), were synthesized by traditional approaches. The structure and purity of the monomers was confirmed by FTIR, 1H NMR, and 13C NMR spectra. The thermally activated polymerization of the MDP‐Bz and DPA‐Bz afforded thermosetting polybenzoxazines with higher Tg's, 270 °C and 208 °C respectively, and higher crosslinking density compared to BPA‐Bz, due to the transesterification or esterification reactions occurred during curing process. These reactions are in accordance with the number of independent reactions determined analyzing by SVD the chemical rank of the IR spectra data matrices recorded along the homopolymerization reactions monitored at 200 °C. Spectral and concentration profiles of the active chemical species involved in these processes were obtained by MCR‐ALS. © 2011 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2011 相似文献
9.
Lucas Montero De Espinosa Juan C. Ronda Marina Galià Virginia Cádiz Michael A.R. Meier 《Journal of polymer science. Part A, Polymer chemistry》2009,47(21):5760-5771
The acyclic diene metathesis (ADMET) polymerization of a phosphorus‐containing α,ω‐diene prepared from a plant oil derived building block is reported. Different ruthenium based metathesis catalysts and conditions were tested to optimize the ADMET polymerization of this monomer. Undecylenyl undecenoate was used as fully renewable comonomer to obtain polyesters with different phosphorus contents and to increase the renewable content of the final polymers. Copolymerization caused marked variations in the molecular weights leading to polyesters from 6 to 38 KDa. The effect of the ADMET polymerization temperature in the thermal properties of the copolymers was studied and their thermal degradation and flame retardant properties were evaluated. © 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 47: 5760–5771, 2009 相似文献
10.
Three laccase temperature isoforms were isolated and purified to homogeneity from the xerophyte plant species Cereus pterogonus. This catalytically active protein exhibited an apparent molecular mass of 137 kDa, 90 kDa, and 43 kDa. Under reducing conditions the enzyme yielded a subunit molecular mass of 43 kDa alone, suggesting that the enzyme is a multimer of its subunits. The enzyme exhibited an optimum pH of 10 with 2,6-dimethoxyphenol used as a substrate. The 137 and 90 kDa forms yielded optimum activity at 90°C; whereas the 43 kDa molecular form yielded optimum activity at 60°C. The enzyme kinetic constant Km remained closely similar for all three enzyme forms, whereas Vmax varied by 25 % overall. The catalytic activity remained above its t1/2 value in excess of the 30 min denaturation assay period at 60°C and 90°C. These high-temperature isoforms of the plant laccase enzyme with alkaline pH optima can find great industrial use. 相似文献