Non-planar iodinated pyrrole structures were found through DFT calculations of geometry optimization, when doping one pyrrole molecule with iodine atoms. This take us to a new mono-iodinated pyrrole structure in which one pyrrole molecule is attacked with one iodine atom in a pyramidal configuration. Then, the pyrrole molecule was attacked with two and until four optimized linear iodine atoms in a pyramidal structure configuration. The corresponding potential energy curves were also constructed in order to know what kind of adsorption (physisorption or chemisorption) is obtained, considering physisorption as lower than ten kcal/mol, and chemisorption greater than twenty kcal/mol according to the literature. Finally, it is known that halogenated pyrrole is a highly conductive material required in several fields.

This work shows the development of several models for chain-growth polymerizations that admit the direct calculation of the complete molecular weight distribution of the polymer. The direct and complete calculation implies that no statistical mean values are employed as in the moments method neither numerical approximations like in the minimum-squared based methods. The free radical polymerization of ethylene (LDPE) and the coordination via metallocenes polymerization of ethylene (HDPE) are taken as examples for analysis.

In the free radical polymerization case, the conventional scheme for chain-growth polymerization is adopted, with steps for initiation, propagation, chain transfer to small species and the additional step of chain transfer to dead chains [1]. The kinetic parameter are obtained from the open literature. Two kind of reactors were modelled: batch and continuous stirred tank reactor. For this last case, a simulation strategy was considered in which the run started from an initial known population of dead chains. Results show that typical non-linear polymerization profiles for the molecular weight distribution are obtained. For the coordination polymerization of ethylene via metalocenes, the standard coordination model was employed [2]. A two-site catalyst was considered and kinetic parameters reported in the open literature were used. For this study an experimental program in a lab-scale reactor was undertaken in order to obtain modelling data [3]. Results show that the standard model adequately reproduces the experimental data in the kinetic and molecular attributes of the polymer.

Cardiovascular diseases, frequently associated to the formation of aneurisms, are the mayor cause of mortality and morbidity in the world. Due to the increased need for the regeneration of arteries and veins, several natural and synthetic biopolymers such as poly(glycerol sebacate), PGS, have been studied to make blood vessel constructs. PGS elastomeric properties develop after it is crosslinked; however, the poor solubility of the material limits the process to fabricate useful constructs for tissue engineering by electrospinning, casting, or other methods. The structure and properties of electrospun scaffolds made from soluble poly(glycerol sebacate) and poly(ε- caprolactone), are reported here. Soluble PGS oligomers (o-PGS) of different molecular weight, obtained by the polycondensation reaction of sebacic acid and glycerol, were analyzed, including molecular structure, physical properties and solubility. Temperature, reactor atmosphere, and time of reaction strongly influenced the solubility, the molecular weight and molecular structure. To improve o-PGS processing and properties it was mixed with PCL to make electrospun scaffolds. In order to process the mixture by electrospinning, homogeneous solutions o-PGS and PCL were prepared. Because PCL is hydrophobic and o-PGS is hydrophilic selected solvent mixtures were tested to form the homogeneous solutions; the materials dissolved in a mixture of THF:DMF:DCM. Typical electrospinning parameters for preparing the tubular scaffolds at room conditions were: voltage 17.5 kV, needle-collector distance 20 cm and, relative humidity 30-35%, flow injection 0.5 to 2.0 ml/h. The initial mechanical properties of the biodegradable scaffolds were better than those made of natural grafts; the Young’s modulus ranged from 7.6 to 13.0 MPa, depending on electrospinning process parameters. The morphology and physical properties of electrospun PGS/PCL tubular scaffolds show useful features not found in similar constructs made by other methods. The 3D tubular scaffolds were built-up of layered porous walls to produce constructs of different pore size and fibers of different diameter. The porous area was one to two orders of magnitude higher than those produced at micrometer scale by conventional melting and dry/wet spinning methods. These scaffolds show useful characteristics for regenerative medicine such as physical properties; nanometric diameters; high surface/volume ratio; and potentiallity for adhesion and growth of living cells.

New organic materials with semiconductor behavior were prepared from diphenyldiacetylene and aromatic amines with withdrawing groups by Reisch-Schulte reaction and characterized by IR, RMN spectroscopy. The obtained materials share the property of having electron withdrawing groups joint to the attached aromatic ring, it seems this feature accounts in large fashion to improve the semiconducting behavior of this kind of substances, this topic was studied by means theoretical calculations and the results are also discussed. The calculations were carried out by means the Gaussian09 software and all the involved species were geometrically optimized.

Activation of carbon using polypyrrole as activating agent is searched through Molecular Modeling. The Geometry Optimizations carried out helped to observe carbon effect when is attacked by a polymer in order to give an estimation of the pore size diameter of carbon. In this first approximation pore size diameters is about 30 % with respect to BET (Brunauer, P. Emmett y E. Teller) isotherms experimental data.

In recent decades conducting polymers have attracted attention due to their promising and versatile applications in different fields. There is a considerable interest in the application of nanotubes multilayer carbon (MWCNT) because of their unique structure, high electrical conductivity, high chemical stability, and high surface-to-volume ratio. These properties make MWCNT extremely attractive for fabricating sensors. Composites based on a matrix of a biopolymer such as the chitosan (CS) with a lot of conductive polymers or (MWCNT), have received increasing attention due to their attractive structural, mechanical and electrical properties that could have applications in different fields such as tissue engineering, biomedicine, and manufacture of sensors and biosensors. Have been reported conducting polymer composites with an extensive range of interesting mechanical and electrical properties, which is reported in this paper to obtain films by ultrasonic bath mixing of Chitosan 3% w/v using polypyrrole (PPy) and multilayer carbon nanotubes. Surface characterization was performed using scanning electron microscopy (SEM). The electrical properties were analyzed using electrochemical impedance spectroscopy (EIS) in a frequency range 0.01 - 10E+5 Hz to 10 mV AC. The results show that the films of CS/PPy/MWCNT have a homogeneous distribution where the chitosan envelops the loads, while for EIS retention load was observed within the matrix observing these materials in accordance with the equivalent circuit of Warburg showing diffusional process.

Polymer-clay nanocomposites are compounds in which nanoclay particles are distributed in a polymer matrix. Epoxy-clay nanocomposites have become a very interesting topic among researchers in the past two decades because nanoclays have a positive effect on the mechanical, thermal and especially barrier anticorrosive performance of the polymers. In this study, epoxy-montmorillonite organoclay (OMMT) nanocomposite coatings were prepared and deposited on carbon steel substrates. The coatings were prepared through in situ polymerization and by UV-curing technique. The OMMT was added to epoxy resin at loadings between 0 wt.% and 5 wt.%, the particles of OMMT were dispersed using forced agitation-sonication and deposited on carbon steel coupons. The nanocomposite coatings obtained have been characterized by scanning electron microscopy (SEM), spectroscopy Fourier transform infrared (FTIR), X-ray diffraction (XRD), thermogravimetric analysis (TGA), and evaluated their corrosion protection effect on cold rolled carbon steel coupons by performing visual analysis. The X-ray analysis showed that exfoliation occurred for the OMMT in the polymer matrix, the SEM analysis showed that OMMT was homogenous dispersed in the polymer matrix and the coatings were uniform. The FTIR analysis showed the characteristic bands of epoxy resin and OMMT in the composite. The results showed that 1 wt.% OMMT coating exhibit better anticorrosive properties than pure epoxy.

In this paper, the formation of Langmuir-Blodgett films of poly(p-acryloylaminophenylmethylphosphonic) acid polymers, with general formula (C10H12NPO4)n are reported. The Langmuir-Blodgett (LB) technique was used for building ordered nanostructures in molecular assemblies of these polymers, which were able to form stable films. At the air-water interface, these polymers (with low and high molecular weight) formed Langmuir (L) monolayers, which were characterized by surface pressure versus molecular area (π-A) isotherms and Brewster´s Angle Microscopy (BAM). Using the LB method, molecular mono and multilayer films of these polymers were prepared and transferred onto glass substrates forming Z-type multilayers, with a transfer ratio close to unity. These LB films were characterized by Atomic Force Microscopy (AFM).

Polypeptides are receiving increasing attention as building blocks to create nanostructures for biomedical applications. The first goal of this investigation was to explore the influence of the reaction conditions in the synthesis of well-defined dendritic graft (arborescent) polypeptides from amine-terminated poly(γ-benzyl L-glutamate) (PBG) chains. The optimization was carried out in terms of the reaction temperature, solvent, reaction time, and mole ratio of reactants and coupling agents. Size exclusion chromatography served to evaluate the grafting reaction in terms of grafting yield (fraction of side chains coupled with the substrate) and coupling efficiency (fraction of coupling sites consumed on the substrate). The maximum grafting yield and coupling efficiency achieved were 67% and 74%, respectively. These arborescent PBG substrates were subsequently grafted with poly(ethylene oxide) segments forming a hydrophilic shell, to obtain water-dispersible unimolecular micelles useful as delivery vehicles for doxorubicin.

Were synthesized four new hybrid hardener agents type amino tertiary functionalized with allyl groups from : l, 6-Hexanediamine, Diethylenetriamine, Trietilentriamine and Tris (2-aminoethyl) amine, using the basic nucleophilic substitution mechanism, replacing bromide by amino tertiary group in the presence of tetrabutylammonium bromide as phase transfer agent, producing allyl amine corresponding: ALA-4, ALA-5, ALA-6 and TRIS respectively, which were evaluated as a hardening of epoxy resin DGEBA through photopolymerization process by UV ligth curing, adding a 10, 20 and 40% molar percentage of hybrid materials and the thiol corresponding to carry out the thiol-ene reaction (TMP TMP, PTKMP) with DMPA as initiator. The resinic materials obtained, were evaluated by the technique of dynamic mechanical analysis (DMA) at a heating rate of 5° C/min in a range from - 50° C to 150° C in nitrogen atmosphere. The formulations with hybrid hardening agent ALA 4- 20% -PTKMP and TRIS 10% -PTKMP were the materials with modulus 2289, 2971 Mpa and tgs of 102,103°C, respectively.

In the last decades the interest in organic conductors has growth, so they have become the object of study of many research groups that are interested in developing new materials with important conducting properties. The charge transfer complexes (CTC) represent an important kind of organic conductors, because they exhibit high conductivity values, as well as versatility for their design.

In this work, the charge transfer complex (CTC) formed by substituted pyrrole and tetrathiofulvalene (TTF) was obtained by means electrochemical synthesis, the resultant colored mix was characterized by Mass spectrometry, NMR and EPR studies, its intrinsic electronic behavior was measured by a four point probe method, besides theoretical calculations were carried out on the possible structures of the resultant molecular adduct. All the results show that there is a net transfer of an electron between both organic moieties in a solution giving place to a semiconductor species.