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Surface coating is a method used for protection against corrosion and environmental impact for metals. In the case of solid surfaces, coatings can be achieved by radio-frequency magnetron sputtering or other corrosion-resistant substances, which may involve the deposition of one or more layers, depending on the procedure involved, modifying the morphology of the surface and surface area. This work aims to study the relationship of two surface morphological methods through roughness and fractal dimension measurements in top-surface coatings, bilayer Ti/WTiN/WTiC (named as n = 1); multilayer [Ti/WTiN/WTiC] (named as n = 40) deposited by RF-magnetron sputtering. The measurements were obtained by profilometer and image processing pixel intensity. The topography of each coating exhibited texture with impurities as domes distributed in small cluster island types. The surface roughness were 9.42 and 18.63 nm; fractal dimension measurements were 2.55 and 2.32, respectively, with a low correlation between roughness and fractal dimension. The R-squared analysis exhibited a good relationship between the fractal dimension values, tending linear regression negative. The result of factorial design 22 confirmed the performance correlation and linear regression analyses. The fractal dimension measurements by the optical method can be great potential to evaluate surface roughness complementary in applications such as laboratories and even in scale industrial. Thus the result of statistical treatment shows high accuracy in the measurements.

Exploitation of the "ocotillo" tree (Fouquieria splendens Engelm) to produce ocotillol/ocotillone (o/o) in Northern Mexico hasn't been explored to this date. In the present work, isolation of ocotillol/ocotillone was performed through a batch reactor, which allowed the elimination of alcohol and phenols present in the ocote plant, yielding only resins and waxes from the ocote trunks. The ocotillol/ocotillone was extracted from the remaining resin on the ocote logs by solvent extraction in a batch reactor, to be crystallized after its extraction using a rotary evaporator. FTIR, and NMR analysis exhibited the characteristic ginsenoside bands, while the UV-vis spectrum of ocotillol/ocotillone depicted an absorption band belonging to the O-H bonds, indicating that the group is anchored to the ginsenoside structure and not due to a water signal. Lastly, the thermogravimetric analysis described a common behavior among other ginsenosides. Production of ocotillo/ocotillone has an energy consumption of 3624 kWh/gr. With a cost of $0.478 USD in laboratory equipment, which translates as a plausible sustainable production of ocotillol/ocotillone.

Hydrogels are commonly used as Drug Delivery Systems (DDS) as patches due to its ability to store drug molecules within their structures. The release can be activated under certain stimuli, such as temperature and pH. In this paper, the mathematical modelling of acetaminophen release in hydroxypropyl cellulose with polyacrylamide (HPC/PAAm) is reported. The HPC/PAAm gel was synthesized in proportions of 25/75 wt% and was characterized by FTIR, DSC, optical microscopy, SEM, and TGA, with and without acetaminophen. The release tests were performed for hypothermic, normal, and febrile human body conditions, at 35, 37, and 39°C, respectively, on two release media: water and phosphate buffer solution. In order to describe the release of acetaminophen in HPC/PAAm gel, a genetic programming algorithm was used to accomplish Multigene Symbolic Regression (MSR). Characterization results showed that the drug was crystallized on the surface of the HPC/PAAm gel. Release test results showed that several simultaneous processes occurred in the acetaminophen diffusion phenomenon. A unique mathematical model was obtained by MSR. This model was able to describe the release of acetaminophen in HPC/PAAm gel with high values of R2 and adjusted R2 and to simulate the drug release at times beyond the end of the experiment. High values of R2 and low values of Coefficient of Variation (CV), Root-Mean-Square Error (RMSE), and Mean Absolute Error (MAE) were obtained from the comparison between the simulated and the experimental data. This allows to conclude that the mathematical model is reliable to represent and simulate the acetaminophen release in HPC/PAAm gel at 35, 37, and 39°C.

Multiple nanostructures of graphene oxide (GO) and Zinc oxide (ZnO) have been prepared via alcoholic reduction of GO, where took place the ZnO incorporation with different weight ratios. Th...

In the present work, we prepare Cellulose Nanofibers Films (CNFs) incorporating silver nanostructures (Ag/AgCl nanocubes) in a ratio of 1–20 wt% to the organic matrix. We found that with the increase of Ag wt%, a raise in crystalline species corresponding to Ag/AgCl was observed. The diffraction pattern in 2Ө = 44.7° planes belonging to Ag (2 0 0) shifts to 2Ө = 45.45° with planes AgCl (2 2 0), due to the increase of Ag. Furthermore, we describe that incrementation in silver concentration aid in fibers gaining a higher arrangement. Scanning Electron Microscopy (SEM) images showed cubic structures formed by smaller cubic nanostructures. Electrochemical Impedance tests determined electrical resistance of the films, obtaining values of 551 Ω cm2, 62.6 Ω cm2, 3.78 Ω cm2, 7.9 Ω cm2, and 15.8 Ω cm2 for concentrations of 1 wt%, 5 wt%, 10 wt%, 15 wt%, and 20 wt% respectively; in addition to obtaining the CPE from films, demonstrating that they possess electrical conduction and energy storage capabilities.

A novel bio-inspired algorithm, namely, Dingo Optimization Algorithm (DOA), is proposed for solving optimization problems. The DOA mimics the social behavior of the Australian dingo dog. The algorithm is inspired by the hunting strategies of dingoes which are attacking by persecution, grouping tactics, and scavenging behavior. In order to increment the overall efficiency and performance of this method, three search strategies associated with four rules were formulated in the DOA. These strategies and rules provide a fine balance between intensification (exploitation) and diversification (exploration) over the search space. The proposed method is verified using several benchmark problems commonly used in the optimization field, classical design engineering problems, and optimal tuning of a Proportional-Integral-Derivative (PID) controller are also presented. Furthermore, the DOA’s performance is tested against five popular evolutionary algorithms. The results have shown that the DOA is highly competitive with other metaheuristics, beating them at the majority of the test functions.

The curing reaction of the epoxy system “diglycidyl ether of bisphenol-A” (DGEBA) and the tertiary amine “2-[(2-dimethyl-amino)-ethoxy] ethanol” (DMAE), with different DMAE concentrations was studied by means of rheometric analysis using the Rubber Process Analyzer (RPA). A novel simple technique was introduced in order to allow the use of the RPA instrument in measuring the curing studies of quasi liquid reactants. It was found that the crosslinking degree; as measured by: a)- the maximum torque in the RPA analysis as well as by b)- the estimated molecular weight between crosslinks (Mc); increased with the DMAE concentration. Also, it was found that the curing reaction rate, increased with the DMAE concentration; greatly decreasing the time to gel point as well as the time to maximum torque. The degree of crosslinking, as taken from the crosslink density or by the molecular weight between crosslinks, increases roughly seven times as the tertiary amine (DMAE) concentration increases from 3 to 10 wt%. The activation energy of the crosslinking reaction was determined by plotting as an Arrhenius type equation, the log(Geltime) -vs- the inverse temperature, and it was found to be around 42.9 kJ/mol.

Graphene oxide (GO) nanocomposites doped with DEGUSSA (P25) was synthetized by (GO) alcoholic reduction at high temperatures, during the reduction the P25 anchored to the spaces left by car...

espanolLa corrosion causa grandes perdidas y danos catastroficos en plantas industriales y en la infraestructura. Entre los metodos para reducirla se encuentran los recubrimientos. El uso de recubrimientos multicapa metal-ceramico es eficiente para disminuir la corrosion en aceros, es considerada una opcion viable, ya que ofrecen diversas ventajas respecto a los recubrimientos de una capa: una de estas ventajas es que son depositadas con espesores relativamente altos y son capaces de disipar las tensiones residuales que se forman durante el crecimiento de recubrimientos delgados, lo cual mantiene su adhesion al sustrato. Los recubrimientos se depositaron por erosion ionica con magnetron, utilizando blancos de Ti y W. Se disenaron y depositaron dos arquitecturas de multicapas que incluye recubrimientos de nitruro de tungsteno (WN) y nitruro de tungsteno titanio (WTiN) con bicapas alternadas de Ti/TiN y W/WN. Esas dos secuencias de deposito de capas se indentificaron como A con mas capas Ti y B de mayor contenido de W, ambas constan de un proceso de deposito de nueve capas. La estructura se estudio por difraccion de rayos X y la morfologia y composicion por SEM y EDS respectivamente. La superficie se estudio con perfilometria y microscopia de fuerza atomica. El comportamiento electroquimico se analizo en una solucion NaCl por medio de polarizaciones potencio-dinamicas y espectroscopia de impedancia electroquimica (EIS). Los resultados de difraccion de rayos X muestran la presencia de dos fases de WN. El tamano de grano del recubrimiento A es similar al obtenido en el recubrimiento B. La morfologia de las multicapas mostro una superficie en su mayoria lisa, con presencia de domos esfericos, asi como grietas en ambos recubrimientos, siendo mas abundantes en el recubrimiento B. En su seccion transversal, se observa la secuencia de las multicapas compuestas por capas de Ti, W, TiN, WTiN y WN, pero en algunos casos no se aprecia el cambio entre las capas individuales y dos capas permanecen como una sola en las imagenes de SEM. Los resultados electroquimicos obtenidos mediante curvas de polarizacion potenciodinamica mostraron un corrimiento del potencial de corrosion hacia valores mas nobles. La corriente de corrosion en el recubrimiento A con mas capas de contenido de Ti, es menor comparada con la del recubrimiento B, ambas mejoran la resistencia a la corrosion del sustrato. Este comportamiento se confirmo a traves del diagrama de Nyquist obtenido por EIS. EnglishCorrosion causes great losses and catastrophic damages in industrial plants and infrastructure, among the methods to reduce it are the coatings. The use of metal-ceramic multilayer coatings to reduce corrosion in steels is a viable option, since they offer several advantages over single-layer coatings, among which, they can be deposited with relatively high thicknesses and are able to dissipate the residual stresses that form during the growth of the thin films, which maintains its adhesion to the substrate. The coatings were deposited by magnetron Sputtering, using Ti and W targets. Two multilayer architectures were designed and deposited, including tungsten nitride (WN) and titanium tungsten nitride (WTiN) coatings with alternated bilayers of Ti/TiN and W/WN, those two deposition sequences of layer were identified as A with more Ti and B layers with higher W content; both consist of a nine-layer deposit process. The structure was studied by X-ray diffraction and the morphology and composition by SEM and EDS respectively. The surface was studied with profilometry and atomic force microscopy. The electrochemical behavior was analyzed in a sodium chloride solution by means of potentiodynamic polarizations and electrochemical impedance spectroscopy (EIS). X-ray diffraction results show the presence of two phases of WN. The grain size of coating A is similar to that obtained in coating B. The morphology of the multilayers showed a mostly smooth surface but with the presence of spherical domes, as well as cracks in both coatings, being more abundant in the coating B. In its cross section, the sequence of multilayers composed of layers of Ti, W, TiN, WTiN and WN is observed, however in some cases the change between the individual layers is not observed and two layers remain as one in the images of MEB. The electrochemical results obtained by potentiodynamic polarization curves showed a shift of the corrosion potential towards more noble values. The corrosion current in coating A with more layers of Ti is lower than coating B and both improve the corrosion resistance of the substrate. This behavior was confirmed in the Nyquist diagram obtained by EIS.

The styrene-butadiene-styrene (SBS) is a thermoplastic copolymer commonly used as pressure sensitive adhesive (PSA), due its they are highly flexible and elastics, that produce high cohesive strength that results in physical interactions caused by polystyrene (PS) blocks. However, SBS-based PSA’s restrain their adhesion properties around their glass transition temperature (Tg), so it is necessary to add a crosslinking agent to increase their thermal resistance. Crosslinking is an important process in adhesives formulations, due that the mechanical properties of adhesive improve, but not enough information I published about the kinetic of that process. One of most studied crosslinking agent for adhesive formulations is dicumyl peroxide (DCP), which shows a good combination of physical and chemical properties to adhesive during crosslinking process. This report presents a crosslinking process using DCP as crosslinking agent. The study of kinetic parameters was determined by differential scanning calorimetry (DSC) in isothermal and dynamic conditions, from which the order of the crosslinking process reaction was found to be first order, according to the Kissinger and Ozawa models. The adhesive and cohesive strength was evaluated through the failure criterion between the bonds of the adhesive line using the single lap join method (SLP), showing that the best performance was that of the formulation made from resin Sylvalite RE100L and 0.81phr of DCP.

In this study, the combination of organomodified montmorillonite (MMT), magnesium hydroxide (MDH), graphene oxide (GO) and expandable graphite (EG) as intumescent flame retardant for Linear...

The effect of three different organomodified nanoclays (Cloisite 20A, Cloisite 30B, and Nanomer I28E) as well as the effect of a compatibilizer (PEgMA) was studied, with the purpose of developing g...

The effect of acrylic acid (AA) and amine alcohol (DMAE) functionalization via plasma of carbon nanofibers (CNF) on physical and mechanical properties of polypropylene-CNF nanocomposites prepared by melt mixing was studied. The behavior of these functionalized CNF via plasma was compared with a CNF functionalized by oxidation with a mixture of sulphuric acid (H2SO4) and nitric acid (HNO3). Two different types of compatibilizers were used: an amine alcohol modified PP (PPgDMAE) and a maleic anhydride grafted PP (PPgMA). The CNF functionalization was evidenced by Raman spectroscopy, comparing the ratio of peaks at 1371 and at 1590 cm−1. Dispersion of the CNF was assessed using scanning microscopy, and the effect of the type of CNF functionalization on the dispersion was evidenced. A noticeable increase in thermal stability, mechanical and electrical properties and crystallization rate were observed. For example, the storage modulus when using PPgDMAE and AA functionalized CNF increased up to 48% over the control. The mechanical properties of flexural and impact strength showed an effective load transfer when using this CNF and compatibilizer system, which was attributed to the better functionalized CNF dispersion and the strong interactions between this CNF and the polymer matrix. POLYM. COMPOS., 2017. © 2017 Society of Plastics Engineers

Selective harmonics elimination (SHE) is a widely applied control strategy in multilvel inverters for harmonics reduction. SHE is designed for the elimination of low-order harmonics while keeping the fundamental component equal to any previously specified amplitude. This paper proposes a novel bio-inspired metaheuristic optimization algorithm called Black Widow Optimization Algorithm (BWOA) for solving the SHE set of equations. BWOA mimics the spiders’ different movement strategies for courtship-mating, guaranteeing the exploration and exploitation of the search space. The optimization results show the reliability of BWOA compared to the state-of-the-art metaheuristic algorithms and show competitive results as a microalgorithm, opening its future application for an on-line optimization calculation in low requirement hardware.

In the present work, the evaluation of chicken feather particles (CFP) and styrene-butadiene/chicken feather (SBS-CF) composites as modifiers for asphalt binder is presented. It is well known that elastomers are the best asphalt modifiers, because their thermoplastic behavior assists asphalts in improving the range of their mechanical properties at both low and high temperatures. Nowadays, the use of natural products and byproducts as fillers for polymer matrices has been a matter of research, and the field of asphalt modification is not the exception. Chicken feather particles (CFP) is a waste material whose main component is keratin, which offers remarkable properties. In the present work, CFP was used as a filler of a styrene-butadiene rubber matrix (SBS) with radial structure, to obtain a composite intended as an asphalt modifier. Besides, raw CFP was also tested as an asphalt modifier. Physical, thermal and rheological properties of the modified asphalts were evaluated in order to determine their degree of modification with respect to the original asphalt. The results show that the addition of raw CFP improves some physical properties as penetration and decreases the phase separation, furthermore, the asphalt modified with CFP displayed similar rheological properties to those shown by the asphalt modified with SBS, while some other properties resulted in being even better, like the phase separation, with the advantage that the CFP comes from a natural waste product.

Nitride and carbide ternary coatings improve the wear and corrosion resistance of carbon steel substrates. In this work, Ti-W-N and Ti-W-C coatings were deposited on AISI 1060 steel substrates using reactive radio frequency (RF) magnetron sputtering. The coatings were designed as monolayers, bilayers, and multilayers of 40 periods. The coatings were obtained with simultaneous sputtering of Ti and W targets. The microstructure, composition, and electrochemical properties were investigated by techniques such as X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM), atomic force microscopy (AFM), electrochemical impedance spectroscopy (EIS), and potentiodynamic polarization. XRD results shower a mix of binary TiN and W2N structures in the Ti-W-N layer, a ternary phase in Ti-W-C layers, in addition of a quaternary phase of Ti-W-CN in the multilayers. The analysis of the XPS demonstrated that the atomic concentration of Ti was more significant than W in the Ti-W-N and Ti-W-C layers. The lowest corrosion rate (0.19 mm/year−1) and highest impedance (~10 kΩ·cm2) out of all coatings were found in n = 40 bilayers. In the simulation of equivalent electrical circuits, it was found that the Ti-W-N coating presented three processes of impedance (Pore resistance + Coating + Inductance). However, the multilayer (n = 40) system presented a major dielectric constant through the electrolyte adsorption, therefore, this caused an increase in the capacitance of the coating.

Monodispersed silver nanoparticles (Ag-NPs) were synthesized by chemical reduction in aqueous medium and transferred in chloroform to be redispersed in the plasticized matrix of poly(l-lactic acid) (PLA) by melt compounding. PLA nanocomposites were prepared using a combination of Ag-NPs in amounts of 0.01, 0.025, 0.05, 0.075 and 0.1% in weight, with 10 pph (parts per hundred) of glycerol triacetate (GTA) to be characterized by UV–Vis and Fourier transformed infrared (FTIR) spectroscopy, differential scanning calorimetry (DSC) and dynamic mechanical analysis (DMA). Optical properties showed that PLA nanocomposites have monodispersed Ag-NPs due to the intense SPR (surface plasmon resonance) absorption band at 414 nm, with a calculated particle size of ~30 nm. The crystallinity is gradually raised at a maximum level (21.1%) compared to the pure PLA (2.3%) and T g drastically decreased from 61 to 36.8 °C when Ag-NPs are incorporated in the plasticized PLA matrix. These results were consistent with the enhanced elastic modulus in DMA analysis, explained from the viewpoint of a good nanofiller dispersion and crystallization behavior, providing a stable and ordered crystal (α-form) in agreement with FTIR and DSC analysis. Finally, the outcomes indicate a synergistic effect between Ag-NPs and the plasticizer GTA, due to the nucleating effect of the monodispersed Ag-NPs and the mobility chain promoted by the plasticizer in the macromolecular arrangement of the PLA.

Poly (l-lactic acid) nanocomposites based on silver nanoparticles (PLA/AgNP) were prepared by melt blending using a twin screw extruder. Nanocomposites at low concentrations were prepared with 0.1, 0.2, and 0.3 wt% of AgNP to enhance the crystallinity and improve the thermal and mechanical properties of PLA. AgNPs smaller than 100 nm which increased the crystallinity of PLA upon the addition were detected by UV–Vis. Crystallinty index of nanocomposites was estimated reaching a maximum of 0.52, where the AgNPs acted as heterogeneous nucleating agent which is correlated with the Ag content. The α and α′ crystals were observed by temperature modulated differential scanning calorimetry and wide angle X-ray diffraction, thus lattice spacing of more ordered and distorted crystals were corroborated obtaining a higher fraction of α structures when a high content of nanoparticles was added. Moreover, strain at break and toughness of pure PLA were increased from 4.3% to 16.9% and 2.1 to 7.3 MJ/m3, respectively, modifying the inherent brittleness of PLA. Finally, with the obtained results a correlation was established where more disordered crystals show less resistance to deformation that lead to an enhancement of elongation at break observed in the nanocomposites. POLYM. COMPOS., 2016. © 2016 Society of Plastics Engineers

Graphene oxide (GO) derived from oxidation of natural graphite contains many active groups that can interact with a great variety of polar moieties. In this work, polypropylene (PP)/graphene oxide nanocomposites using polypropylene (PP) grafted with amine-alcohol (PPgDMAE) as compatibilizer were prepared by two different methods. Maleic anhydride grafted PP (PPgMA) was reacted with 2-[2-(dimethylamine)-ethoxy] ethanol (DMAE) in the melt for forming amine-alcohol functionalized polypropylene (PPgDMAE). Nanocomposites were prepared by two methods. In one method, PP/GO nanocomposite was prepared by direct melt mixing in an internal batch mixer using PPgDMAE as compatibilizer. In another method, a previous mixing of PPgDMAE with GO in hot Xilene was done and then, once the solvent was evaporated, it was incorporated into PP by melt-mixing. The microstructure and interface enhancement of the prepared composites were analyzed by Fourier transform infrared spectroscopy (FTIR), Raman, X-ray difraction (DRX) contact angle, scanning and transmission electron microscopy (STEM), mechanical, thermal, and electrical properties measurements. Fourier transform infrared spectroscopy (FTIR) revealed the interaction between GO and PPgDMAE. The loading of GO conducted to enhance the composite mechanical properties attributed to the strong interfacial interactions between GO and PPgDMAE. A significant improvement in mechanical thermal stability and electrical properties was observed when nanocomposites were prepared by the solution blending method compared with melt mixing method. This work suggests a potential application of GO in preparation of high performance PP composites. POLYM. COMPOS., 2016. © 2016 Society of Plastics Engineers

The utilization of organic industrial wastes as source for production of cellulose nanocrystals (CNCs) is very attractive and has a huge advantage in comparison with traditional sources as plants, bacterial or commercial cellulose (MCC), because it has the potential of increasing the value chain of these materials. The aim of this study is to analyze the utilization of Euphorbia Antisyphilitica bagasse, a waste of the wax industry, as source for CNC’s prepared by two different techniques, namely acid hydrolysis and TEMPO mediated oxidation. Cellulose extraction was performed by a treatment with aqueous NaOH followed by a bleaching process with NaClO. The samples were characterized by X-ray diffraction, Fourier transform infrared spectroscopy, thermogravimetric analysis, scanning electron microscopy, and conductometric titration. The CNCs samples have a diameter of around 17 nm and a length between 220 and 310 nm with a degree of crystallinity above 70 % and a very different thermal behavior depending of the isolation method. On one hand charge densities are 2.135 e/nm² and 1.933 e/nm², on the other hand root-mean-square roughness is around 2.1 and 2.3 nm (films were deposited on a glass surface), depending on the isolation technique.

One of the most significant applications of modified asphalts is the asphalt pavement design industry. Asphalts are mainly modified by using polymeric materials; however, the actual increase in organic waste materials demands that special attention be paid on their management and final disposal. As a consequence, attractive alternatives involving reusing organic wastes, such as in asphalt modification technology, have emerged as efficient ways of handling them. Chicken feathers (CF) are considered as organic waste material from the chicken breeding industry. Incorporating CF into asphalt can reduce problems in pavement design due to its economic, technical, and ecological advantages. This work studies the effect of adding chicken feather bioparticles (CFBP) into asphalt, taking a mixture of asphalt modified with radial-structured styrene–butadienestyrene copolymer (SBS) as a reference. Preliminary tests were carried out in order to establish the experimental limitations due to the unknown properties of the CFBP. The rheological behavior of asphalt-polymer blends (AP) and asphalt-bioparticles mixtures (ACFBP) at 2, 4, and 6 wt%, were evaluated. Modified asphalt blends resulted in improved rheological properties such as complex modulus (G*), elastic modulus (G′), viscous modulus (G″), as well as in the reduction of the phase angle (δ), which has been related to better resistance to permanent deformations. The behavior of the ACFBP blend at 2% was comparable to that of AP blend at the same modifier concentration; however, ACFBP showed better storage stability, which is a relevant result considering that phase separation is one of the main obstacles for using SBS in paving technology. According to the overall results, modifying asphalt with CFBP is not only a more sustainable and cleaner way of producing surface roads, but it also may lead to cost reduction, due to the potential replacement of synthetic polymer with organic waste, without affecting the final properties of the asphalt blend.

In this work, isotactic polypropylene (iPP) nanocomposites were prepared containing silver nanoparticles (Ag-NPs) with a novel and easy method, using polyethylene glycol (PEG) as reducing agent and surface modifier. Ag-NPs were prepared using different amounts in weight of silver nitrate into PEG to induce the formation of Ag-NPs. PP/Ag nano compounds were prepared by melt blend method: single-screw extruder and internal Brabender mixer. The effects of Ag-NPs and PEG on the crystallization, morphology, thermal, and mechanical properties were evaluated. Ag-NPs with a particle size of 80 nm and typical growth of the β-form in iPP were observed. The presence of PEG in samples of PP/Ag-NPs was detected by infrared spectrometry and the peak characteristic of Ag-NPs by ultraviolet–visible analysis. X-Ray diffraction patterns and differential scanning calorimetry thermograms showed the β-phase formation in both of the dispersion methods, but Brabender mixer showed higher percentages of crystallinity (31% of β-phase). The elongation at break was increased and it was directly dependent on the relative amount of crystalline β-phase. PEG is an excellent precursor to get Ag-NPs and a good interface modifier of iPP.

Nanocomposites based on cyclic olefin copolymer/linear low density polyethylene blends (COC/LLDPE) with various contents of three different modified organoclays (20A, 10A, and I28E) compatibilized with polyethylene grafted maleic anhydride (PEgMA) were prepared by met mixing. The influence of content and type of organoclay and compatibilizer on nanocomposite morphology, thermal, and mechanical properties as well as on oxygen and water vapour barrier properties was determined. X-ray diffraction (XRD) and transmission microscopy (TEM) were used to investigate the clay dispersion, which showed a strong dependence on compatibilizer and type of organoclay. An exfoliated–intercalated morphology was obtained for compatibilized samples of C20A and I28E organoclays at 5 wt%. A less intercalated structure was obtained for samples with C10A. The exfoliated–intercalated structure was influenced both by the compatibilizer and the increase on the nanocomposite viscosity due to the COC incorporation as was determined by Rheological measurements. Mechanical analysis gave an evidence of increasing stiffness after nanoclay was added into COC/LLDPE blend matrix observing higher Young modulus for the compatibilized samples. A notorious decrease of Oxygen and Water vapour permeation rate was observed for COC/LLDPE blend films nanocomposites only when using C20A and I28E clays. These results can be useful in the design of sustainable flexible films for the packaging requirements of specific types of food. POLYM. COMPOS., 2015. © 2015 Society of Plastics Engineers

Gold nanoparticles were synthesized at room temperature and atmospheric pressure using fructose, a common and non-toxic monosaccharide. The nanoparticles were mostly spherical, with a homogenous shape and a small size distribution. Fructose was a reducing and stabilizing agent, and the stability of the nanoparticles depended on its concentration.

In this work, we investigated the effect of four different configurations at the exit of a single-screw extruder on the induction of beta phase in PP for four different rotational speeds. The configuration of a breaker plate with 120 orifices of 1-mm diameter and 7-mm length each, give the highest content of beta-phase (56.92%), for a screw rotational speed of 20 rpm. It was due to the shear caused separation of the melt when it passes through the orifices of the breaker plate. The breaker plate of configuration 4 (breaker plate with the greatest number of orifices) provided the largest number of contacts between the melt and the orifice walls resulting in chain alignment. The results show that the beta-phase can be induced in the polymer without any further additives, especially without any nucleating agents, but rather by using a special breaker plate configuration at the exit of the single-screw extruder. The skin-core structure of the polymer was only developed with one type of extruder configuration. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 130: 2932–2937, 2013

The β-phase in polypropylene (PP) induced by shear rate in a single-screw extruder was studied. PP samples were extruded with and without a breaker plate at the exit of the extruder at five different screw rotational speeds: 20, 40, 60, 80, and 100 rpm. Differential scanning calorimeter was used to observe the melting behavior of the samples. The β-phase was quantified by wide angle X-ray diffraction. Extruded samples with a breaker plate showed higher values of β-phase of PP than those extruded without a breaker plate. With a breaker plate, the maximum percentage of β-phase was observed at 60 rpm (19.9%), whereas the maximum β-phase content without breaker plate was observed at 40 rpm (13.6%). The higher level of β-phase with the breaker plate was attributed to the shear rate induction and to the orientation by shear of the polymer chains through the orifices of the breaker plate. POLYM. ENG. SCI., 2012. © 2012 Society of Plastics Engineers

The objective of the present work is to analyze the different mesophases observed in a gel synthesized from hydroxypropyl cellulose (HPC) and polyacrylamide (PAAm) and its phase behavior in water. Hydroxypropyl cellulose is a material derived from cellulose it is non toxic and degradable. HPC is widely used in pharmaceutics, food additives, stabilizer, thickener, etc., HPC is approved by the FDA for use in the food industry. HPC has the characteristic that it forms liquid crystals, depending on the solvent and on the concentration of the polymer. In this work a lower critical solution temperature (LCST) and an upper critical solution temperature (UCST) were observed, the resulting gel showed anisotropic, nematic and cholesteric phases in water, the phase formed depended on the concentration of the polymer.

The variations of the cross-linking agent, initiator, and molar ratio in the synthesis of a semi-interpenetrating polymer network (IPN) of polyurethane-starch/polymethyl methacrylate (PMMA) were studied for their viscoelastic and morphologic properties. The synthesized semi-IPNs were evaluated by means of dynamic mechanical analysis (DMA), finding that a relationship exists between the quantity of cross-linker and the storage module, where alpha and beta relaxations are present in the polymethyl methacrylate's rigid chains, and this peak widens upon increasing the quantity of PMMA in the semi-IPN. The morphology of the semi-IPNs shown by SEM and AFM micrographies suggests that 0.5 wt.% of initiator and 3 wt.% of cross-linker demonstrate uniform surfaces.

In this article we report the removal of Pb, Ni and Cu using a hydrogel made with hydroxypropyl cellulose (HPC) and polyacrylamide (PAAm). The hydrogel successfully removed those metals, as shown by the results of atomic absorption spectroscopy; the polymer removed 53% of Pb, 52% of Ni and 51% of Cu. Different pHs were tried for these polymers. The highest metal removal was found at 40°C. The adsorption kinetics fitted Langmuir and Freundlich isotherms. Metal particles were detected on the hydrogel with electron microscopy and energy–dispersive X–ray spectroscpy, confirming that the gel removed the metals from the testing solutions. This polymer is a good option for treating wastewater and industrial waters as it removes metals and is composed of nontoxic materials. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016, 133, 43285.

La síntesis de geles de hidroxipropilcelulosa / Poliacrilamida mediante radiación de microondas, son una propuesta en la química verde o sustentable, se tiene un tiempo menor de reacción, por espectroscopia de Infrarroja demuestran tener la misma estructura química, la temperatura de transición vítrea se presentan separación de fases. El estudio de hinchamiento del gel en agua, demostró que tiene mayor capacidad de retener agua hasta un 3000 peso% que su peso inicial, comparado con los geles sintetizados por métodos convencionales se tiene un l 0% más por el método de radiación de microondas.