Alertas Tecnológicas - 3er Trimestre
1. Alertas Tecnológicas 2017 Julio-Septiembre 3 er Trimestre
12. Alertas Tecnológicas 2017 Julio-Septiembre 3 er Trimestre
3. Application of ammonia pretreatment to enable enzymatic hydrolysis of hardwood biomass. Polymer Degradation and Stability, 148, 19-25. Sakuragi, K., Igarashi, K., & Samejima, M. (2018). Ammonia pretreatment greatly improves enzymatic hydrolysis of grass biomass, but is reported to be ineffective for hardwood biomass. Here, we examined the effectiveness of ammonia pretreatment of biomass from six hardwood species with different contents of xylan and lignin. Ammonia pretreatment greatly improved enzymatic hydrolysis of polysaccharides in birch and willow, but was less effective for acacia, eucalyptus, and poplar. The effectiveness of ammonia pretreatment increased with xylan content but decreased with lignin content of the hardwood species. By adding a recombinant xylanase to the commercial enzyme digestion cocktail, the yield of enzymatic hydrolysis of ammonia-pretreated birch biomass was improved to a similar level to that obtained with grass biomass. Our results indicate that enzymatic hydrolysis of biomass from hardwood species having a relatively high xylan/lignin ratio can be achieved with a xylanase-enriched enzyme cocktail after ammonia pretreatment. Alertas Tecnológicas 2017 Julio-Septiembre 3 er Trimestre Enzimas y degradación de plásticos, encapsulación de enzimas, degradación de plásticos, alternativas a los vertidos plásticos, regeneración medioambiental, obtención de plásticos biodegradables. 2
5. Intrinsic conductivity mechanisms of radical polymer films with conjugated and non-conjugated backbones. Bulletin of the American Physical Society. Park, A., Zhang, Y., Cintora, A., McMillan, S., Harmon, N., Moehle, A., ... & Fuchs, G. (2018). Radical polymers, which incorporate a stable radical pendent group such as 2,2,6,6-tetramethyl pipiridine-1-oxyl (TEMPO), form as class of non-toxic, environmentally friendly materials for battery electrodes. Their conductivity in the solid phase, while critical for battery electrode applications because of the need to collect current, have been controversial. Here we discuss our study of DC conductivity in several species of radical polymers. First, we prepared poly(2,2,6,6-tetramethylpiperidinyloxy methacrylate) (PTMA) using several synthetic methods to examine if the previously proposed redox hopping mechanism is sensitive to the preparation details. We found that PTMA is an insulator, implying that few radical sites participate in conductivity. In search of a radical polymer with higher conductivity, we also investigated the properties of a radical polymer with a conjugated backbone. Our results show that although introducing conjugation to the backbone is a route to introduce conductivity to a radical polymer, the steric hindrance from the TEMPO groups limit the size of the ordered conjugated crystal domains and thus severely reduce the conductivity as compared to the conjugated backbone without TEMPO. Alertas Tecnológicas 2017 Julio-Septiembre 3 er Trimestre Nuevos polímeros orgánicos, con propiedades mejoradas de porosidad y resistencia térmica, más ligeros que los polímeros tradicionales, Nuevas funcionalidades poliméricas como fluorescencia, conductividad eléctrica o iónica y actividad catalítica 1
7. Biodegradable Polymeric Materials in Degradable Electronic Devices. ACS Central Science. Feig, V. R., Tran, H., & Bao, Z. (2018). Biodegradable electronics have great potential to reduce the environmental footprint of devices and enable advanced health monitoring and therapeutic technologies. Complex biodegradable electronics require biodegradable substrates, insulators, conductors, and semiconductors, all of which comprise the fundamental building blocks of devices. This review will survey recent trends in the strategies used to fabricate biodegradable forms of each of these components. Polymers that can disintegrate without full chemical breakdown (type I), as well as those that can be recycled into monomeric and oligomeric building blocks (type II), will be discussed. Type I degradation is typically achieved with engineering and material science based strategies, whereas type II degradation often requires deliberate synthetic approaches. Notably, unconventional degradable linkages capable of maintaining long- range conjugation have been relatively unexplored, yet may enable fully biodegradable conductors and semiconductors with uncompromised electrical properties. While substantial progress has been made in developing degradable device components, the electrical and mechanical properties of these materials must be improved before fully degradable complex electronics can be realized. Alertas Tecnológicas 2017 Julio-Septiembre 3 er Trimestre Nuevos polímeros orgánicos, con propiedades mejoradas de porosidad y resistencia térmica, más ligeros que los polímeros tradicionales, Nuevas funcionalidades poliméricas como fluorescencia, conductividad eléctrica o iónica y actividad catalítica 3
8. Rotaxanes As Mechanochromic Fluorescent Force Transducers in Polymers. Journal of the American Chemical Society. Sagara, Y., Karman, M., Verde-Sesto, E., Matsuo, K., Kim, Y., Tamaoki, N., & Weder, C. (2018). The integration of mechanophores, motifs that transduce mechanical forces into chemical reactions, allows creating materials with stress-dependent properties. Typical mechanophores are activated by cleaving weak covalent bonds, but these reactions can also be triggered by other stimuli, and this renders the behavior unspecific. Here we show that this problem can be overcome by extending the molecular-shuttle function of rotaxanes to mechanical activation. A mechanically interlocked mechanophore composed of a fluorophore-carrying macrocycle and a dumbbell-shaped molecule containing a matching quencher was integrated into a polyurethane elastomer. Deformation of this polymer causes a fluorescence turn- on, due to the spatial separation of fluorophore and quencher. This process is specific, efficient, instantly reversible, and elicits an easily detectable optical signal that correlates with the applied force. Alertas Tecnológicas 2017 Julio-Septiembre 3 er Trimestre Nuevos polímeros orgánicos, con propiedades mejoradas de porosidad y resistencia térmica, más ligeros que los polímeros tradicionales, Nuevas funcionalidades poliméricas como fluorescencia, conductividad eléctrica o iónica y actividad catalítica 4
10. Cellulose Reinforced Biodegradable Polymer Composite Film for Packaging Applications. In Bionanocomposites for Packaging Applications (pp. 49-69). Springer, Cham. Khalil, H. A., Tye, Y. Y., Leh, C. P., Saurabh, C. K., Ariffin, F., Fizree, H. M., ... & Suriani, A. B. (2018). This chapter provides a broad overview of bionanocomposite film prepared from various biodegradable polymers reinforced with nanocellulose. In nature, biodegradable polymer exhibits relatively weaker properties than the synthetic polymers. Incorporation of cellulose into the biopolymer matrix has improved the mechanical, thermal, and barrier properties of the resulting biopolymer film significantly. This achievement has encouraged their application as packaging material. Since they have a huge potent ial in the future, further investigation of this composite material is crucial. Alertas Tecnológicas 2017 Julio-Septiembre 3 er Trimestre Nuevos desarrollos en polímeros biodegradables 2
11. The Response of Manicaria saccifera Natural Fabric Reinforced PLA Composites to Impact by Fragment Simulating Projectiles. In Advances in Natural Fibre Composites (pp. 89-98). Springer, Cham. Quintero, S., Porras, A., Hernandez, C., & Maranon, A. (2018). This chapter presents the impact behavior of a recently developed green composite material made of Manicaria saccifera natural fabric reinforced Poly- Lactic Acid (PLA). Composite coupons made of PLA and Manicaria saccifera fabric were produced by compression molding using the film stacking method. The composite ballistic limit (V50) was determined by subjecting PLA/Manicaria coupons, of varying lay-ups and thicknesses, to ballistic impact loading using fragment simulating projectiles (FSPs) according to the MIL-STD-662F standard. It was found that coupons with areal densities between 0.2 and 0.3 g/cm2 displayed a V50 between 50 and 70 m/s. Also, it was found that t he V50 increased nonlinearly as a function of coupon thickness, but it does not depend on the composite stacking sequence. Finally, the energy absorbed by the material at impact on complete penetrations is uniform and independent of the striking velocity, whereas for partial penetrations increases exponentially. Alertas Tecnológicas 2017 Julio-Septiembre 3 er Trimestre Nuevos desarrollos en polímeros biodegradables 3
2. Enzyme-assisted polymer film degradation-enabled biomolecule sen sing with poly (N-isopropylacrylamide)-based optical devices. Analytica chimica acta, 999, 139-143. Zhang, W., Wei, M., Carvalho, W. S., & Serpe, M. J. (2018). A biosensor for mouse Immunoglobulin G (IgG) was generated from responsive polymer-based interference filters (etalons). To accomplish this, an excess amount of alkaline phosphatase-modified goat anti-mouse IgG (AP-GAM, F(abâÄô)2 fragment specific to mouse IgG) was added to mouse IgG, and allowed to react for some time. After a given reaction time, the bound AP-GAM could be isolated from the unbound, excess AP-GAM by addition of goat anti-mouse IgG (Fc fragment specific)-modified magnetic microspheres (GAM-M) that bind the mouse IgG bound to AP-GAM. After application of a magnetic field, the free, unbound AP-GAM was isolated from the mixture and exposed to an etalon that has its upper Au surface modified with phosphate-containing polymer that can be degraded by AP-GAM. By the phosphate-containing polymer being degraded by the excess AP-GAM, the cleaved phosphate groups can diffuse into the interference filter's active polymer layer that yields a change in the optical properties that can be related to the amount of IgG in the sample. This concept is extremely straightforward to implement, and can be modified to detect a variety of other analytes of interest. Alertas Tecnológicas 2017 Julio-Septiembre 3 er Trimestre Enzimas y degradación de plásticos, encapsulación de enzimas, degradación de plásticos, alternativas a los vertidos plásticos, regeneración medioambiental, obtención de plásticos biodegradables. 1
4. Effect of Hydroxyl Monomers on the Enzymatic Degradation of Poly (ethylene succinate), Poly (butylene succinate), and Poly (hexylene succinate). Polymers, 10(1), 90. Bai, Z., Liu, Y., Su, T., & Wang, Z. (2018). Poly(ethylene succinate) (PES), poly(butylene succinate) (PBS), and poly(hexylene succinate) (PHS), were synthesized using succinic acid and different dihydric alcohols as materials. Enzymatic degradability by cutinase of the three kinds of polyesters was studied, as well as their solid-state properties. The biodegradation behavior relied heavily on the distance between ester groups, crystallinity, and the hydrophilicity-hydrophobicity balance of polyester surfaces. The weight loss through degradation of the three kinds of polyesters with different hydroxyl monomers took place in the order PHS > PBS > PES. The degradation behavior of the polyesters before and after degradation was analyzed by scanning electron microscopy, differential scanning calorimetry, powder X-ray diffraction, Fourier transform infrared spectroscopy, gel permeation chromatography, and thermogravimetric analysis. The decrease in relative intensity at 1800-1650 estedpolyesters were degraded simultaneously. The frequencies of the crystalline and amorphous bands were almost identical before and after degradation. Thus, enzymatic degradation did not change the crystalline structure but destroyed it, and the degree of crystallinity markedly decreased. The molecular weight and polydispersity index only changed slightly. The thermal stability of the three kinds of polyesters decreased during enzymatic degradation. Alertas Tecnológicas 2017 Julio-Septiembre 3 er Trimestre Enzimas y degradación de plásticos, encapsulación de enzimas, degradación de plásticos, alternativas a los vertidos plásticos, regeneración medioambiental, obtención de plásticos biodegradables. 3
6. A facile approach towards fabrication of lightweight biodegradable poly (butylene succinate)/carbon fiber composite foams with high electrical conductivity and strength. Composites Science and Technology Kuang, T., Ju, J., Yang, Z., Geng, L., & Peng, X. (2018). . Lightweight electrically conductive biodegradable polymer composites have been considered as a promising environmental-friendly alternative to replace the traditional petroleum-based CPCs because of the economic and ecological drawbacks of petroleum-based plastics. Herein, we demonstrated a facile and effective way to fabricate poly (butylene succinate) (PBS)/carbon fiber (CF) composites foams with lightweight, high-strength and improved conductive networks through the combination of solvent mixing, micro-injection molding and supercritical carbon dioxide (ScCO2) foaming methods. Results showed that the resulting composite foams possessed much higher electrical conductivity (the percolation threshold decreased from 3.6 to 7.4 to 1.04-2.37_vol%), suggesting that the introduction of foaming technique could be beneficial for the formation of effective 3D conductivity networks. The composite foams presented a good compressive strength and a low density (reduced around _50%). Moreover, effects of different length and content of CF on the mechanical and thermal performance, rheological behavior, foaming properties and electrical conductivities of PBS/CF composites have been investigated. Alertas Tecnológicas 2017 Julio-Septiembre 3 er Trimestre Nuevos polímeros orgánicos, con propiedades mejoradas de porosidad y resistencia térmica, más ligeros que los polímeros tradicionales, Nuevas funcionalidades poliméricas como fluorescencia, conductividad eléctrica o iónica y actividad catalítica 2
9. Synthesis, characterization and application of biodegradable pol ymer grafted novel bioprosthetic tissue. Journal of Biomaterials Science, Polymer Edition, 29(3), 217-235. Pal, A., Pathak, C., & Vernon, B. (2018). Animal tissue has an extended history of clinical use in applications like heart valve bioprosthesis devices, cardiovascular surgical applications etc. but often does not last long after implantation in the body due to rapid unwanted degradation. The goal of this work is to develop novel composite biomaterials by grafting biological tissue with synthetic, biodegradable polymers. In the current research phase, porcine submucosa, ureter and bovine pericardial tissue are grafted with poly DL-lactide (PLA), poly glycolide (PGA) and poly DL-lactide glycolide (PLGA) copolymers. The grafted and control tissues are characterized by FTIR and SEM. The biodegradability of the tissue-graft composite materials is determined by pepsin and collagenase digestion assays, showing it can be tailored by varying the grafted polymer type and amount. The grafted tissues can be tuned for a particular clinical or tissue engineering applications including drug delivery with little or no burst release and sustained/controlled delivery. Alertas Tecnológicas 2017 Julio-Septiembre 3 er Trimestre Nuevos desarrollos en polímeros biodegradables 1
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