Molecular mobility. Structure-property relationship of polymeric materials

Tesis por compendio[EN] The present work examines the influence of the chemical structure of polymers on thermal, mechanical and dielectric behavior. The experimental techniques used for the purpose are differential scanning calorimetry, dynamo-mechanical analysis and dielectric spectroscopy. Additionally, in order to confirm the results obtained using the above methods, other techniques such as ray diffraction have also been employed. Chapters 1 and 2 contain the introduction and the objectives, respectively. Chapter 3 briefly describes the experimental techniques used. Chapter 4 contains the findings of the comparative analysis of the response to electrical noise fields for three poly(benzyl methacrylates) with different structures. The analysis was carried out under a wide range of frequencies and temperatures on three poly(benzyl methacrylates) containing two dimethoxy groups in positions 2,5-, 2,3- and 3,4-. The results show that the position of the dimethoxy groups on the aromatic ring has a significant effect on the molecular dynamics of poly(benzyl methacrylate). The spectra obtained were of high complexity and therefore, in order to perform a better analysis, numerical methods for time-frequency transformation including the use of parametric regularization techniques were used. We studied the effect of this structural change on the secondary relaxation processes and relaxation process , relating to the glass transition. We also analyzed the effect of the dimethoxy group position on the formation of nanodomains, in which the side chains are predominant, and on the conduction processes of the materials tested. In Chapter 5, the conductivity of rubbery liquids was studied by analyzing poly(2,3-dimethoxybenzyl methacrylate), which exhibits its own particular behavior. The chapter analyzes the principle of time-temperature superposition, employing different interrelated variables. Chapter 6 focuses on how the presence of crosslinking affects the molecular mobility of polymethacrylates containing aliphatic alcohol ether residues. In this case, the effect of crosslinking on the secondary and primary relaxation processes was analyzed. The creation of nanodomains in the side chains as a result of the presence of crosslinking was also studied.[ES] En este trabajo se presenta un estudio de la influencia de la estructura química de los polímeros en su comportamiento térmico, mecánico y dieléctrico. Las técnicas experimentales empleadas para ello han sido la calorimetría diferencial de barrido, el análisis dinamo-mecánico y la espectroscopia dieléctrica. Adicionalmente, se han empleado otras técnicas como la difracción de rayos, con objeto de corroborar los resultados obtenidos por las primeras. En los Capítulos 1 y 2 se recoge la introducción y los objetivos, respectivamente. El Capítulo 3 presenta una breve descripción de las técnicas experimentales empleadas. En el Capítulo 4 se recogen los resultados obtenidos en el análisis comparativo de la respuesta a campos de perturbación eléctrica en un amplio rango de frecuencias y temperaturas para tres polimetacrilatos de bencilo con dos grupos dimetoxi en posiciones 2,5-, 2,3- y 3,4-. Los resultados obtenidos señalan el importante efecto de la posición de los grupos dimetoxi en el anillo aromático, sobre la dinámica molecular del polimetacrilato de bencilo. Los espectros obtenidos fueron muy complejos, por ello en orden a llevar a cabo un mejor análisis se emplearon métodos numéricos para la transformación tiempo-frecuencia que incluyeron el uso de técnicas de regularización paramétrica. Se ha estudiado el efecto que dicho cambio estructural ejerce tanto sobre los procesos de relajación secundaria como sobre el proceso de relajación α, relacionado con la transición vítrea. Así mismo, se ha analizado el efecto de la posición de los grupos dimetoxi en la formación de iii nanodominios en los que predominan las cadenas laterales, y su efecto en los procesos de conducción de los materiales analizados. En el Capítulo 5 se recoge el estudio de la conductividad de líquidos gomosos tomando como modelo el poli (metacrilato de 2,3-dimetoxibencilo), por su peculiar comportamiento. En este capítulo se ha realizado un análisis del principio de superposición tiempo-temperatura, empleando para ello diferentes variables relacionadas entre sí. En el Capítulo 6 se recoge el efecto de la presencia de entrecruzante en la movilidad molecular de polimetacrilatos que contienen residuos de éteres de alcoholes alifáticos. En este caso, se ha analizado el efecto de la presencia de entrecruzante tanto en los procesos de relajación secundarios, como en el proceso de relajación principal. También se llevó a cabo un análisis del efecto que la presencia de entrecruzante tiene sobre la creación de nanodominios gobernados por las cadenas laterales.[CA] En aquest treball es presenta un estudi de la influència de l'estructura química dels polímers en el seu comportament tèrmic, mecànic i dielèctric. Les tècniques experimentals utilitzades han sigut la calorimetria diferencial de rastreig, l'anàlisi dinamo-mecànic i l'espectroscòpia dielèctrica. Addicionalment, s'han empleat altres tècniques com la difracció de rajos X a fi de corroborar els resultats obtinguts per les primeres. En els Capítols 1 i 2 s'arreplega la introducció i els objectius, respectivament. Al Capítol 3 es presenta una breu descripció de les tècniques experimentals emprades. En el Capítol 4 es recull els resultats obtinguts en l'anàlisi comparativa de la resposta a camps de pertorbació elèctrica en un ampli rang de freqüències i temperatures de tres polimetacrilats de benzil amb dos grups metoxi en posicions 2,5-, 2,3- i 3,4-. Els resultats obtinguts assenyalen l'important efecte de la posició dels grups metoxi en l'anell aromàtic, sobre la dinàmica molecular del polimetacrilat de benzil. Els espectres obtinguts van ser molt complexos, per aquesta raó per a dur a terme un millor anàlisi es van emprar mètodes numèrics per a la transformació temps-freqüència que van incloure l'ús de tècniques de regularització paramètrica. S'ha estudiat l'efecte que el dit canvi estructural exerceix tant sobre els processos de relaxació secundària com sobre el procés de relaxació , relacionat amb la transició vítria. Així mateix, s'ha analitzat l'efecte de la posició dels grups metoxi en la formació de nanodominis en els que predominen les cadenes laterals, i el seu efecte en els processos de conducció dels materials analitzats. En el Capítol 5 s'arreplega l'estudi de la conductivitat de líquids gomosos prenent com a model el poli-(metacrilat de 2,3-dimetoxibencilo), pel seu peculiar comportament. En aquest capítol s'ha realitzat un anàlisi del principi de superposició temps-temperatura, emprant per a això diferents variables relacionades entre sí. En el Capítol 6 s'arreplega l'efecte de la presència d'entrecreuat en la mobilitat molecular de polimetacrilats que contenen residus d'èters d'alcohols alifàtics. En aquest cas, s'ha analitzat l'efecte de la presència d'entrecreuat tant en els processos de relaxació secundaris, com en el procés de relaxació principal. També es va dur a terme un anàlisi de l'efecte que la presència d'entrecreuat químic té sobre la creació de nanodominis governats per les cadenes laterals.Carsí Rosique, M. (2015). Molecular mobility. Structure-property relationship of polymeric materials [Tesis doctoral]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/59460TESISPremios Extraordinarios de tesis doctoralesCompendi

Thermal and Dielectric Characterization of Multi-Walled Carbon NanotubesThermoplastic Polyurethanes Composites

[EN] Multi-walled carbon nanotubes-thermoplastic polyurethanes composites were characterized by means of differential scanning calorimetry and dielectric relaxation spectroscopy. The composite is characterized by two glass transition temperatures T (g) . The T (g) associated with the soft segment decreases by increasing of carbon nanotubes content, while carbon nanotubes content has practically no effect on the value of the T-g associated with the hard segments. It was observed that rising the temperature and carbon nanotubes content resulted in the increased of both the dielectric permittivity and the loss factor. The presence of carbon nanotubes produces an enhancement of charge carriers trapping, increasing the electrical conductivity. The electrical conductivity of the composite was found to exhibit an insulator to conductor transition at a carbon nanotubes critical content, i.e., the percolation threshold, near 6 wt %.MJS and MC acknowledge the financial support of the DGCYT through Grant MAT2015-63955-R.Sanchis Sánchez, MJ.; Carsí Rosique, M.; Gracia-Fernandez, C. (2017). Thermal and Dielectric Characterization of Multi-Walled Carbon NanotubesThermoplastic Polyurethanes Composites. Polymer Science Series A. 59(4):543-553. https://doi.org/10.1134/S0965545X17040083S543553594D. W. Schaefer and R. S. Justice, Macromolecules 40 (24), 8501 (2007).D. R. Raul and L. M. Robeson, Polymer 49 (15), 3187 (2008).P. J. Brigandi, J. M. Cogen, and R. A. Pearson, Polym. Eng. Sci. 54 (1), 1 (2014).H. Deng, L. Lin, M. Ji, S. Zhang, M. Yang, and Q. Fu, Prog. Polym. Sci. 39 (4), 627 (2014).Polymer-Matrix Composites. Types, Applications and Performance, Ed. by R. Kumar (Nova Sci. Publ., New York, 2014).Z. Wenying and Y. Demei, J. Appl. Polym. Sci. 118 (6), 3156 (2010).Y. P. Mamunya, V. V. Davydenko, P. Pissis, and E. V. Lebedev, Eur. Polym. J. 38 (9), 1887 (2002)B. Redondo-Foj, P. Ortiz-Serna, M. Carsí, M. J. Sanchis, M. Culebras, C. M. Gomez, and A. Cantarero, Polym. Int. 64, 284 (2015).S. Deng, Y. Zhu, X. Qi, W. Yu, F. Chen, and Q. Fu, RSC Adv. 6 (51), 45578 (2016).M. Khissi, M. El Hasnaoui, J. Belattar, M. P. F. Graca, M. E. Achour, and L. C. Costa, J. Mater. Environ. Sci. 2 (3), 281 (2011).M. Hindermann-Bischoff and F. Ehrburger-Dolle, Carbon 39 (3), 375 (2001).I. Balberg, Carbon 40 (2), 139 (2002).M. Moniruzzaman and K. I. Winey, Macromolecules 39, 5194 (2006).A. Bharati, R. Cardinaels, J. W. Seo, M. Wubbenhorst, and P. Moldenaers, Polymer 79 (19), 271 (2015)Szycher's Handbook of Polyurethanes, Ed. by M. Szycher (CRC Press, Washington, DC, 1999).C. Prisacariu, Polyurethane Elastomers. From Morphology to Mechanical Aspects (Springer, New York, 2011).P. Król, Prog. Mater. Sci. 52 (6), 915 (2007).P. R. de C. Coelho Filho, M. S. Marchesin, A. R. Morales, and J. R. Bartoli, Mater. Res. 17 (1), 127 (2014).R. H. Baughman, A. A. Zakhidov, and W. A. de Heer, Science 297 (5582), 787 (2002).J. Kim and Y. Son, Polymer 88, 29 (2016)M. A. Nikje Mir and A. Yaghoubi, Polimery 59(11–12), 776 (2014).C. Kingston, R. Zepp, A. Andrady, D. Boverho, R. Fehir, D. Hawkins, J. Roberts, P. Sayre, B. Shelton, Y. Sultan, V. Vejins, and W. Wohlleben, Carbon 68, 33 (2014).Anelastic and Dielectric Effects in Polymeric Solids, Ed. by N. G. McCrum, B. E. Read, and G. Williams (Wiley, London, 1967).In Broadband Dielectric Spectroscopy, Ed. by F. Kremer, and A. Schonhals (Springer, Berlin, 2003).E. Riande and R. Diaz-Calleja, Electrical Properties of Polymers (Marcel Dekker, New York, 2004).I. M. Hodge, K. L. Ngai, and C. T. Moynihan, J. Non-Cryst. Solids 351 (2), 104 (2005).A. Eceiza, M.D. Martin, K. de la Caba, G. Kortaberria, N. Gabilondo, M. A. Corcuera, and I. Mondragon, Polym. Eng. Sci. 48 (2), 297 (2008)A. K. Jonscher, Universal Relaxation Law: A Sequel to Dielectric Relaxation in Solids (Chelsea Dielectrics Press, London, 1996), Chap. 5.A. K. Jonscher, Nature 267, 673 (1977).G. Li, L. Feng, P. Tong, and Z. Zhai, Prog. Org. Coat. 90, 284 (2016)K. Petrie, M. Kontopoulou, and A. Docoslis, Polym. Compos. 37 (9), 2794 (2016)N. Aranburu and J. I. Eguiazabal, Polym. Compos. 35 (3), 587 (2014)Impedance Spectroscopy. Theory, Experiment, and Applications, Ed. by E. Barsoukov and J. R. Macdonals (Wiley Intersci., New York, 2005).S. Havriliak and S. J. Havriliak, Dielectric and Mechanical Relaxation in Materials (Hanser, Munich, 1997), p. 57.S. Havriliak and S. Negami, Polymer 8 (4), 161 (1967)

Effect of Chitin Whiskers on the Molecular Dynamics of Carrageenan-Based Nanocomposites

[EN] Films of carrageenan (KC) and glycerol (g) with different contents of chitin nanowhiskers (CHW) were prepared by a solution casting process. The molecular dynamics of pure carrageenan (KC), carrageenan/glycerol (KCg) and KCg with different quantities of CHWs as a filler was studied using dielectric relaxation spectroscopy. The analysis of the CHW effect on the molecular mobility at the glass transition, T-g, indicates that non-attractive intermolecular interactions between KCg and CHW occur. The fragility index increased upon CHW incorporation, due to a reduction in the polymer chains mobility produced by the CHW confinement of the KCg network. The apparent activation energy associated with the relaxation dynamics of the chains at T-g slightly increased with the CHW content. The filler nature effect, CHW or montmorillonite (MMT), on the dynamic mobility of the composites was analyzed by comparing the dynamic behavior of both carrageenan-based composites (KCg/xCHW, KCg/xMMT).This research was funded by the DGCYT grant number [MAT2015-63955-R] and the Vice-Rectorate for Research of the Pontificia Universidad Catolica del Peru and the the Peruvian Science and Technology Program (INNOVATE-PERU) And The APC was funded by MDPI.Carsí Rosique, M.; Sanchis Sánchez, MJ.; Gómez, CM.; Rodriguez, S.; García-Torres, F. (2019). Effect of Chitin Whiskers on the Molecular Dynamics of Carrageenan-Based Nanocomposites. Polymers. 11(6):1-16. https://doi.org/10.3390/polym11061083116116Zheng, Y., Monty, J., & Linhardt, R. J. (2015). Polysaccharide-based nanocomposites and their applications. Carbohydrate Research, 405, 23-32. doi:10.1016/j.carres.2014.07.016Jamróz, E., Kulawik, P., & Kopel, P. (2019). The Effect of Nanofillers on the Functional Properties of Biopolymer-Based Films: A Review. Polymers, 11(4), 675. doi:10.3390/polym11040675Park, S.-B., Lih, E., Park, K.-S., Joung, Y. K., & Han, D. K. (2017). Biopolymer-based functional composites for medical applications. Progress in Polymer Science, 68, 77-105. doi:10.1016/j.progpolymsci.2016.12.003Xie, F., Pollet, E., Halley, P. J., & Avérous, L. (2013). Starch-based nano-biocomposites. Progress in Polymer Science, 38(10-11), 1590-1628. doi:10.1016/j.progpolymsci.2013.05.002Zhang, R., Wang, X., Wang, J., & Cheng, M. (2018). Synthesis and Characterization of Konjac Glucomannan/Carrageenan/Nano-silica Films for the Preservation of Postharvest White Mushrooms. Polymers, 11(1), 6. doi:10.3390/polym11010006Rhim, J.-W., Park, H.-M., & Ha, C.-S. (2013). Bio-nanocomposites for food packaging applications. Progress in Polymer Science, 38(10-11), 1629-1652. doi:10.1016/j.progpolymsci.2013.05.008Müller, K., Bugnicourt, E., Latorre, M., Jorda, M., Echegoyen Sanz, Y., Lagaron, J., … Schmid, M. (2017). Review on the Processing and Properties of Polymer Nanocomposites and Nanocoatings and Their Applications in the Packaging, Automotive and Solar Energy Fields. Nanomaterials, 7(4), 74. doi:10.3390/nano7040074Shankar, S., Reddy, J. P., Rhim, J.-W., & Kim, H.-Y. (2015). Preparation, characterization, and antimicrobial activity of chitin nanofibrils reinforced carrageenan nanocomposite films. Carbohydrate Polymers, 117, 468-475. doi:10.1016/j.carbpol.2014.10.010Corvaglia, S., Rodriguez, S., Bardi, G., Torres, F. G., & Lopez, D. (2016). Chitin whiskers reinforced carrageenan films as low adhesion cell substrates. International Journal of Polymeric Materials and Polymeric Biomaterials, 65(11), 574-580. doi:10.1080/00914037.2016.1149846Shojaee-Aliabadi, S., Mohammadifar, M. A., Hosseini, H., Mohammadi, A., Ghasemlou, M., Hosseini, S. M., … Khaksar, R. (2014). Characterization of nanobiocomposite kappa-carrageenan film with Zataria multiflora essential oil and nanoclay. International Journal of Biological Macromolecules, 69, 282-289. doi:10.1016/j.ijbiomac.2014.05.015Reddy, M. M., Vivekanandhan, S., Misra, M., Bhatia, S. K., & Mohanty, A. K. (2013). Biobased plastics and bionanocomposites: Current status and future opportunities. Progress in Polymer Science, 38(10-11), 1653-1689. doi:10.1016/j.progpolymsci.2013.05.006Wang, P., Zhao, X., Lv, Y., Li, M., Liu, X., Li, G., & Yu, G. (2012). Structural and compositional characteristics of hybrid carrageenans from red algae Chondracanthus chamissoi. Carbohydrate Polymers, 89(3), 914-919. doi:10.1016/j.carbpol.2012.04.034Byankina (Barabanova), A. O., Sokolova, E. V., Anastyuk, S. D., Isakov, V. V., Glazunov, V. P., Volod’ko, A. V., … Yermak, I. M. (2013). Polysaccharide structure of tetrasporic red seaweed Tichocarpus crinitus. Carbohydrate Polymers, 98(1), 26-35. doi:10.1016/j.carbpol.2013.04.063Stortz, C. A., & Cerezo, A. S. (1992). The 13C NMR spectroscopy of carrageenans: calculation of chemical shifts and computer-aided structural determination. Carbohydrate Polymers, 18(4), 237-242. doi:10.1016/0144-8617(92)90088-8Rodriguez, S. A., Weese, E., Nakamatsu, J., & Torres, F. (2016). Development of Biopolymer Nanocomposites Based on Polysaccharides Obtained from Red AlgaeChondracanthus chamissoiReinforced with Chitin Whiskers and Montmorillonite. Polymer-Plastics Technology and Engineering, 55(15), 1557-1564. doi:10.1080/03602559.2016.1163583Mitsuiki, M., Yamamoto, Y., Mizuno, A., & Motoki, M. (1998). Glass Transition Properties as a Function of Water Content for Various Low-Moisture Galactans. Journal of Agricultural and Food Chemistry, 46(9), 3528-3534. doi:10.1021/jf9709820Picker, K. M. (1999). The use of carrageenan in mixture with microcrystalline cellulose and its functionality for making tablets. European Journal of Pharmaceutics and Biopharmaceutics, 48(1), 27-36. doi:10.1016/s0939-6411(99)00009-0Kasapis, S., & Mitchell, J. R. (2001). Definition of the rheological glass transition temperature in association with the concept of iso-free-volume. International Journal of Biological Macromolecules, 29(4-5), 315-321. doi:10.1016/s0141-8130(01)00180-5Fouda, M. M. G., El-Aassar, M. R., El Fawal, G. F., Hafez, E. E., Masry, S. H. D., & Abdel-Megeed, A. (2015). k-Carrageenan/poly vinyl pyrollidone/polyethylene glycol/silver nanoparticles film for biomedical application. International Journal of Biological Macromolecules, 74, 179-184. doi:10.1016/j.ijbiomac.2014.11.040Arof, A. K., Shuhaimi, N. E. A., Alias, N. A., Kufian, M. Z., & Majid, S. R. (2010). Application of chitosan/iota-carrageenan polymer electrolytes in electrical double layer capacitor (EDLC). Journal of Solid State Electrochemistry, 14(12), 2145-2152. doi:10.1007/s10008-010-1050-8Rescignano, N., Fortunati, E., Armentano, I., Hernandez, R., Mijangos, C., Pasquino, R., & Kenny, J. M. (2015). Use of alginate, chitosan and cellulose nanocrystals as emulsion stabilizers in the synthesis of biodegradable polymeric nanoparticles. Journal of Colloid and Interface Science, 445, 31-39. doi:10.1016/j.jcis.2014.12.032Chang, P. R., Jian, R., Yu, J., & Ma, X. (2010). Starch-based composites reinforced with novel chitin nanoparticles. Carbohydrate Polymers, 80(2), 420-425. doi:10.1016/j.carbpol.2009.11.041Zeng, J.-B., He, Y.-S., Li, S.-L., & Wang, Y.-Z. (2011). Chitin Whiskers: An Overview. Biomacromolecules, 13(1), 1-11. doi:10.1021/bm201564aVillanueva, M. E., Salinas, A., Díaz, L. E., & Copello, G. J. (2015). Chitin nanowhiskers as alternative antimicrobial controlled release carriers. New Journal of Chemistry, 39(1), 614-620. doi:10.1039/c4nj01522cKameda, T., Miyazawa, M., Ono, H., & Yoshida, M. (2005). Hydrogen Bonding Structure and Stability of?-Chitin Studied by13C Solid-State NMR. Macromolecular Bioscience, 5(2), 103-106. doi:10.1002/mabi.200400142MARCHESSAULT, R. H., MOREHEAD, F. F., & WALTER, N. M. (1959). Liquid Crystal Systems from Fibrillar Polysaccharides. Nature, 184(4686), 632-633. doi:10.1038/184632a0Paillet, M., & Dufresne, A. (2001). Chitin Whisker Reinforced Thermoplastic Nanocomposites. Macromolecules, 34(19), 6527-6530. doi:10.1021/ma002049vGopalan Nair, K., & Dufresne, A. (2003). Crab Shell Chitin Whisker Reinforced Natural Rubber Nanocomposites. 1. Processing and Swelling Behavior. Biomacromolecules, 4(3), 657-665. doi:10.1021/bm020127bHuang, Y., Yao, M., Zheng, X., Liang, X., Su, X., Zhang, Y., … Zhang, L. (2015). Effects of Chitin Whiskers on Physical Properties and Osteoblast Culture of Alginate Based Nanocomposite Hydrogels. Biomacromolecules, 16(11), 3499-3507. doi:10.1021/acs.biomac.5b00928Morin, A., & Dufresne, A. (2002). Nanocomposites of Chitin Whiskers from Riftia Tubes and Poly(caprolactone). Macromolecules, 35(6), 2190-2199. doi:10.1021/ma011493aWatthanaphanit, A., Supaphol, P., Tamura, H., Tokura, S., & Rujiravanit, R. (2008). Fabrication, structure, and properties of chitin whisker-reinforced alginate nanocomposite fibers. Journal of Applied Polymer Science, 110(2), 890-899. doi:10.1002/app.28634Salaberria, A. M., Diaz, R. H., Labidi, J., & Fernandes, S. C. M. (2015). Preparing valuable renewable nanocomposite films based exclusively on oceanic biomass – Chitin nanofillers and chitosan. Reactive and Functional Polymers, 89, 31-39. doi:10.1016/j.reactfunctpolym.2015.03.003Rodríguez, S., Gatto, F., Pesce, L., Canale, C., Pompa, P. P., Bardi, G., … Torres, F. G. (2017). Monitoring cell substrate interactions in exopolysaccharide-based films reinforced with chitin whiskers and starch nanoparticles used as cell substrates. International Journal of Polymeric Materials and Polymeric Biomaterials, 67(6), 333-339. doi:10.1080/00914037.2017.1297942Pazmiño Betancourt, B. A., Douglas, J. F., & Starr, F. W. (2013). Fragility and cooperative motion in a glass-forming polymer–nanoparticle composite. Soft Matter, 9(1), 241-254. doi:10.1039/c2sm26800kSanchis, M. J., Carsí, M., Culebras, M., Gómez, C. M., Rodriguez, S., & Torres, F. G. (2017). Molecular dynamics of carrageenan composites reinforced with Cloisite Na+ montmorillonite nanoclay. Carbohydrate Polymers, 176, 117-126. doi:10.1016/j.carbpol.2017.08.012Wu, J., Zhang, K., Girouard, N., & Meredith, J. C. (2014). Facile Route to Produce Chitin Nanofibers as Precursors for Flexible and Transparent Gas Barrier Materials. Biomacromolecules, 15(12), 4614-4620. doi:10.1021/bm501416qSauti, G., & McLachlan, D. S. (2007). Impedance and modulus spectra of the percolation system silicon–polyester resin and their analysis using the two exponent phenomenological percolation equation. Journal of Materials Science, 42(16), 6477-6488. doi:10.1007/s10853-007-1564-3Johari, G. P., Kim, S., & Shanker, R. M. (2007). Dielectric Relaxation and Crystallization of Ultraviscous Melt and Glassy States of Aspirin, Ibuprofen, Progesterone, and Quinidine. Journal of Pharmaceutical Sciences, 96(5), 1159-1175. doi:10.1002/jps.20921Anastasiadis, S. H., Karatasos, K., Vlachos, G., Manias, E., & Giannelis, E. P. (2000). Nanoscopic-Confinement Effects on Local Dynamics. Physical Review Letters, 84(5), 915-918. doi:10.1103/physrevlett.84.915Böhning, M., Goering, H., Fritz, A., Brzezinka, K.-W., Turky, G., Schönhals, A., & Schartel, B. (2005). Dielectric Study of Molecular Mobility in Poly(propylene-graft-maleic anhydride)/Clay Nanocomposites. Macromolecules, 38(7), 2764-2774. doi:10.1021/ma048315cHodge, I. M., Ngai, K. L., & Moynihan, C. T. (2005). Comments on the electric modulus function. Journal of Non-Crystalline Solids, 351(2), 104-115. doi:10.1016/j.jnoncrysol.2004.07.089Havriliak, S., & Negami, S. (2007). A complex plane analysis of α-dispersions in some polymer systems. Journal of Polymer Science Part C: Polymer Symposia, 14(1), 99-117. doi:10.1002/polc.5070140111TSANGARIS, G. M., PSARRAS, G. C., & TSANGARIS, G. M. (1998). Electric modulus and interfacial polarization in composite polymeric systems. Journal of Materials Science, 33(8), 2027-2037. doi:10.1023/a:1004398514901Fulcher, G. S. (1925). ANALYSIS OF RECENT MEASUREMENTS OF THE VISCOSITY OF GLASSES. Journal of the American Ceramic Society, 8(6), 339-355. doi:10.1111/j.1151-2916.1925.tb16731.xTammann, G., & Hesse, W. (1926). Die Abhängigkeit der Viscosität von der Temperatur bie unterkühlten Flüssigkeiten. Zeitschrift für anorganische und allgemeine Chemie, 156(1), 245-257. doi:10.1002/zaac.19261560121Fragiadakis, D., Pissis, P., & Bokobza, L. (2005). Glass transition and molecular dynamics in poly(dimethylsiloxane)/silica nanocomposites. Polymer, 46(16), 6001-6008. doi:10.1016/j.polymer.2005.05.080Rittigstein, P., & Torkelson, J. M. (2006). Polymer-nanoparticle interfacial interactions in polymer nanocomposites: Confinement effects on glass transition temperature and suppression of physical aging. Journal of Polymer Science Part B: Polymer Physics, 44(20), 2935-2943. doi:10.1002/polb.20925Oh, H., & Green, P. F. (2009). Polymer chain dynamics and glass transition in athermal polymer/nanoparticle mixtures. Nature Materials, 8(2), 139-143. doi:10.1038/nmat2354Riggleman, R. A., Yoshimoto, K., Douglas, J. F., & de Pablo, J. J. (2006). Influence of Confinement on the Fragility of Antiplasticized and Pure Polymer Films. Physical Review Letters, 97(4). doi:10.1103/physrevlett.97.045502Doolittle, A. K. (1951). Studies in Newtonian Flow. II. The Dependence of the Viscosity of Liquids on Free‐Space. Journal of Applied Physics, 22(12), 1471-1475. doi:10.1063/1.1699894Doolittle, A. K. (1952). Studies in Newtonian Flow. III. The Dependence of the Viscosity of Liquids on Molecular Weight and Free Space (in Homologous Series). Journal of Applied Physics, 23(2), 236-239. doi:10.1063/1.1702182Plazek, D. J., & Ngai, K. L. (1991). Correlation of polymer segmental chain dynamics with temperature-dependent time-scale shifts. Macromolecules, 24(5), 1222-1224. doi:10.1021/ma00005a044Merino, E. G., Atlas, S., Raihane, M., Belfkira, A., Lahcini, M., Hult, A., … Correia, N. T. (2011). Molecular dynamics of poly(ATRIF) homopolymer and poly(AN-co-ATRIF) copolymer investigated by dielectric relaxation spectroscopy. European Polymer Journal, 47(7), 1429-1446. doi:10.1016/j.eurpolymj.2011.04.006Böhmer, R., Ngai, K. L., Angell, C. A., & Plazek, D. J. (1993). Nonexponential relaxations in strong and fragile glass formers. The Journal of Chemical Physics, 99(5), 4201-4209. doi:10.1063/1.466117Roland, C. M., & Ngai, K. L. (1991). Segmental relaxation and molecular structure in polybutadienes and polyisoprene. Macromolecules, 24(19), 5315-5319. doi:10.1021/ma00019a016Roland, C. M., & Ngai, K. L. (1992). Segmental relaxation and molecular structure in polybutadienes and polyisoprene. [Erratum to document cited in CA115(14):137101w]. Macromolecules, 25(6), 1844-1844. doi:10.1021/ma00032a038Ngai, K. L., & Roland, C. M. (1993). Chemical structure and intermolecular cooperativity: dielectric relaxation results. Macromolecules, 26(25), 6824-6830. doi:10.1021/ma00077a019Roland, C. M. (1992). Terminal and segmental relaxations in epoxidized polyisoprene. Macromolecules, 25(25), 7031-7036. doi:10.1021/ma00051a047Angell, C. A., Poole, P. H., & Shao, J. (1994). Glass-forming liquids, anomalous liquids, and polyamorphism in liquids and biopolymers. Il Nuovo Cimento D, 16(8), 993-1025. doi:10.1007/bf02458784Roland, C. M., & Ngai, K. L. (1996). The anomalous Debye–Waller factor and the fragility of glasses. The Journal of Chemical Physics, 104(8), 2967-2970. doi:10.1063/1.471117Hodge, I. M. (1987). Effects of annealing and prior history on enthalpy relaxation in glassy polymers. 6. Adam-Gibbs formulation of nonlinearity. Macromolecules, 20(11), 2897-2908. doi:10.1021/ma00177a044Hodge, I. M. (1996). Strong and fragile liquids — a brief critique. Journal of Non-Crystalline Solids, 202(1-2), 164-172. doi:10.1016/0022-3093(96)00151-2Roland, C. M., & Ngai, K. L. (1997). Commentary on ‘Strong and fragile liquids - A brief critique’. Journal of Non-Crystalline Solids, 212(1), 74-76. doi:10.1016/s0022-3093(96)00684-9Angell, C. A. (1997). Why C1 = 16–17 in the WLF equation is physical—and the fragility of polymers. Polymer, 38(26), 6261-6266. doi:10.1016/s0032-3861(97)00201-2Angell, C. A. (1995). Formation of Glasses from Liquids and Biopolymers. Science, 267(5206), 1924-1935. doi:10.1126/science.267.5206.1924Angell, C. . (1991). Relaxation in liquids, polymers and plastic crystals — strong/fragile patterns and problems. Journal of Non-Crystalline Solids, 131-133, 13-31. doi:10.1016/0022-3093(91)90266-9Kunal, K., Robertson, C. G., Pawlus, S., Hahn, S. F., & Sokolov, A. P. (2008). Role of Chemical Structure in Fragility of Polymers: A Qualitative Picture. Macromolecules, 41(19), 7232-7238. doi:10.1021/ma801155cSokolov, A. P., Novikov, V. N., & Ding, Y. (2007). Why many polymers are so fragile. Journal of Physics: Condensed Matter, 19(20), 205116. doi:10.1088/0953-8984/19/20/205116Sanchis, M. J., Domínguez-Espinosa, G., Díaz-Calleja, R., Guzmán, J., & Riande, E. (2008). Influence of structural chemical characteristics on polymer chain dynamics. The Journal of Chemical Physics, 129(5), 054903. doi:10.1063/1.295649

Monitoring molecular dynamics of bacterial cellulose composites reinforced with graphene oxide by carboxymethyl cellulose addition

[EN] Broadband Dielectric Relaxation Spectroscopy was performed to study the molecular dynamics of dried Bacterial Cellulose/Carboxymethyl Cellulose-Graphene Oxide (BC/CMC-GO) composites as a function of the concentration of CMC in the culture media. At low temperature the dielectric spectra are dominated by a dipolar process labelled as a beta -relaxation, whereas electrode polarization and the contribution of dc-conductivity dominate the spectra at high temperatures and low frequency. The CMC concentration affects the morphological structure of cellulose and subsequently alters its physical properties. X-ray diffractometry measurements show that increasing the concentration of CMC promotes a decrease of the Ia/Ib ratio. This structural change in BC, that involves a variation in inter- and intramolecular interactions (hydrogen-bonding interactions), affects steeply their molecular dynamics. So, an increase of CMC concentration produces a significantly decrease of the -relaxation strength and an increase of the dc-conductivity.This work was supported by the DGCYT [MAT2015-63955-R]; the Vice-Rectorate for Research of the Pontificia Universidad Catolica del Peril and the National Council of Science, Technology and Technological Innovation of Peru (CONCYTEC/FONDECYT).Sanchis Sánchez, MJ.; Carsí Rosique, M.; Gomez, CM.; Culebras, M.; Gonzales, K.; Gisbert Torres, F. (2017). Monitoring molecular dynamics of bacterial cellulose composites reinforced with graphene oxide by carboxymethyl cellulose addition. Carbohydrate Polymers. 157:353-360. https://doi.org/10.1016/j.carbpol.2016.10.00135336015

Renewable polyol obtained by microwave-assisted alcoholysis of epoxidized soybean oil: Preparation, thermal properties and relaxation process

[EN] The soybean oil polyol (SOP) use as feedstock in the polyurethane industry has been recently emphasized due to its excellent resistance to hydrolysis, which is also applicable in coatings and thermal insulation. In this article, the SOP was obtained by a very fast microwave-assisted alcoholysis of epoxidized soybean oil (ESO). The preparation method, thermal properties, and relaxation process were evaluated. High yields as opening and consumption epoxy group and selectivity of 99.8 mol%, 985 mol%, and 71.2 mol% were obtained. Through titrations, nuclear magnetic resonance and gel permeation chromatography were identified parameters as 0.32 mg KOH.g(-1) acid number, 190 mg KOH.g(-1) hydroxyl number, 150 mg KOH.g(-1) saponification index, 0.17 wt% water content, 1463 g.mol(-1) molecular weight, 4.98 average functionality, 2.4 x 10(-5) mPa.s(-1) viscosity at 333 K and 1.00 g.cm(-3) density. The dielectric relaxation spectroscopy allowed identifying the alpha-relaxation process with a 193.5 K glass transition (T-g), 63.2 fragility index and 234.1 kJ mol(-1) activation energy associated with T-g from the dynamic fragility index. The ionic conductivity temperature dependence on SOP obeys Arrhenius behavior. In summary, the SOP structure and thermal relaxation parameters determination are fundamental for the understanding of the structure-properties relationship of renewable polyurethanes. (C) 2019 Published by Elsevier B.V.The authors thank the financial support from the Brazilian Agency Coordenacao de Aperfeicoamento de Pessoal de Nivel Superior (CAPES) and Sindicato das Industrias de Material Plastic do Nordeste Gaucho (SIMPLAS) for the gratification received at Jovens Pesquisadores 2017, da University of Caxias do Sul (UCS). CAF and OB are National Council for Scientific and Technological Development (CNPq) fellows. CMG and MJS thank the Spanish Ministerio de Economia y Competitividad (MAT2015-63955-R) for partial financial help. The authors also thank Dr. Cesar H. Wanke for the suggestions. This work was supported by CNPq-Brazil (06086/2018-2).Favero, D.; Marcon, VR.; Barcellos, T.; Gomez-Clari, CM.; Sanchis Sánchez, MJ.; Carsí Rosique, M.; Figueroa, CA.... (2019). Renewable polyol obtained by microwave-assisted alcoholysis of epoxidized soybean oil: Preparation, thermal properties and relaxation process. Journal of Molecular Liquids. 285:136-145. https://doi.org/10.1016/j.molliq.2019.04.078S13614528

The effect of cross-linking on the molecular dynamics of the segmental and β Johari–Goldstein processes in polyvinylpyrrolidone-based copolymers

The effect of the cross-link density on the molecular dynamics of copolymers composed of vinylpyrrolidone (VP) and butyl acrylate (BA) was studied using differential scanning calorimetry (DSC) and dielectric relaxation spectroscopy (DRS). A single glass transition was detected by DSC measurements. The dielectric spectra exhibit conductive processes and three dipolar relaxations labeled as a, b and g in the decreasing order of temperatures. The cross-linker content affects both a and b processes, but the fastest g process is relatively unaffected. An increase of cross-linking produces a typical effect on the a process dynamics: (i) the glass transition temperature is increased, (ii) the dispersion is broadened, (iii) its strength is decreased and (iv) the relaxation times are increased. However, the b process, which possesses typical features of a pure Johari Goldstein relaxation, unexpectedly loses the intermolecular character for the highest cross-linker content.B.R.F., M.J.S., P.O.S. and M.C. gratefully acknowledge CICYT for grant MAT2012-33483. F.G. and J.M.G. acknowledge the Spanish Ministerio de Economia y Competitividad-FEDER (MAT2014-54137-R) and the Junta de Castilla y Leon (BU232U13).Redondo Foj, MB.; Sanchis Sánchez, MJ.; Ortiz Serna, MP.; Carsí Rosique, M.; García, JM.; García, FC. (2015). The effect of cross-linking on the molecular dynamics of the segmental and β Johari–Goldstein processes in polyvinylpyrrolidone-based copolymers. Soft Matter. 11:7171-7180. https://doi.org/10.1039/c5sm00714cS7171718011V. Bühler , Polyvinylpyrrolidone Excipients for Pharmaceuticals: Povidone, Crospovidone and Copovidone , Springer , Berlin , 2005Haaf, F., Sanner, A., & Straub, F. (1985). Polymers of N-Vinylpyrrolidone: Synthesis, Characterization and Uses. Polymer Journal, 17(1), 143-152. doi:10.1295/polymj.17.143Gallardo, A., Rocío Lemus, A., San Román, J., Cifuentes, A., & Díez-Masa, J.-C. (1999). Micellar Electrokinetic Chromatography Applied to Copolymer Systems with Heterogeneous Distribution. Macromolecules, 32(3), 610-617. doi:10.1021/ma981144pDevine, D. M., & Higginbotham, C. L. (2005). Synthesis and characterisation of chemically crosslinked N-vinyl pyrrolidinone (NVP) based hydrogels. European Polymer Journal, 41(6), 1272-1279. doi:10.1016/j.eurpolymj.2004.12.022Devine, D. M., Devery, S. M., Lyons, J. G., Geever, L. M., Kennedy, J. E., & Higginbotham, C. L. (2006). Multifunctional polyvinylpyrrolidinone-polyacrylic acid copolymer hydrogels for biomedical applications. International Journal of Pharmaceutics, 326(1-2), 50-59. doi:10.1016/j.ijpharm.2006.07.008Jin, S., Gu, J., Shi, Y., Shao, K., Yu, X., & Yue, G. (2013). Preparation and electrical sensitive behavior of poly (N-vinylpyrrolidone-co-acrylic acid) hydrogel with flexible chain nature. European Polymer Journal, 49(7), 1871-1880. doi:10.1016/j.eurpolymj.2013.04.022Borns, M. A., Kalakkunnath, S., Kalika, D. S., Kusuma, V. A., & Freeman, B. D. (2007). Dynamic relaxation characteristics of crosslinked poly(ethylene oxide) copolymer networks: Influence of short chain pendant groups. Polymer, 48(25), 7316-7328. doi:10.1016/j.polymer.2007.10.020Qazvini, N. T., & Mohammadi, N. (2005). Dynamic mechanical analysis of segmental relaxation in unsaturated polyester resin networks: Effect of styrene content. Polymer, 46(21), 9088-9096. doi:10.1016/j.polymer.2005.06.118Cook, W. D., Scott, T. F., Quay-Thevenon, S., & Forsythe, J. S. (2004). Dynamic mechanical thermal analysis of thermally stable and thermally reactive network polymers. Journal of Applied Polymer Science, 93(3), 1348-1359. doi:10.1002/app.20569Viciosa, M. T., Rouzé, N., Dionísio, M., & Gómez Ribelles, J. L. (2007). Dielectric and mechanical relaxation processes in methyl acrylate/tri-ethyleneglycol dimethacrylate copolymer networks. European Polymer Journal, 43(4), 1516-1529. doi:10.1016/j.eurpolymj.2007.01.043Jobish, J., Charoen, N., & Praveen, P. (2012). Dielectric properties and AC conductivity studies of novel NR/PVA full-interpenetrating polymer networks. Journal of Non-Crystalline Solids, 358(8), 1113-1119. doi:10.1016/j.jnoncrysol.2012.02.003Bekin, S., Sarmad, S., Gürkan, K., Keçeli, G., & Gürdağ, G. (2014). Synthesis, characterization and bending behavior of electroresponsive sodium alginate/poly(acrylic acid) interpenetrating network films under an electric field stimulus. Sensors and Actuators B: Chemical, 202, 878-892. doi:10.1016/j.snb.2014.06.051F. Kremer and A.Schönhals , Broadband Dielectric Spectroscopy , Springer-Verlag , Berlin Heidelberg, New York , 2003Roland, C. M. (1994). Constraints on Local Segmental Motion in Poly(vinylethylene) Networks. Macromolecules, 27(15), 4242-4247. doi:10.1021/ma00093a027Patil, P. N., Rath, S. K., Sharma, S. K., Sudarshan, K., Maheshwari, P., Patri, M., … Pujari, P. K. (2013). Free volumes and structural relaxations in diglycidyl ether of bisphenol-A based epoxy–polyether amine networks. Soft Matter, 9(13), 3589. doi:10.1039/c3sm27525fCasalini, R., & Roland, C. M. (2010). Effect of crosslinking on the secondary relaxation in polyvinylethylene. Journal of Polymer Science Part B: Polymer Physics, 48(5), 582-587. doi:10.1002/polb.21925Carsi, M., Sanchis, M. J., Diaz-Calleja, R., Riande, E., & Nugent, M. J. D. (2012). Effect of Cross-Linking on the Molecular Motions and Nanodomains Segregation in Polymethacrylates Containing Aliphatic Alcohol Ether Residues. Macromolecules, 45(8), 3571-3580. doi:10.1021/ma202811pCarsí, M., Sanchis, M. J., Díaz-Calleja, R., Riande, E., & Nugent, M. J. D. (2013). Effect of slight crosslinking on the mechanical relaxation behavior of poly(2-ethoxyethyl methacrylate) chains. European Polymer Journal, 49(6), 1495-1502. doi:10.1016/j.eurpolymj.2012.12.012Kalakkunnath, S., Kalika, D. S., Lin, H., Raharjo, R. D., & Freeman, B. D. (2007). Molecular Dynamics of Poly(ethylene glycol) and Poly(propylene glycol) Copolymer Networks by Broadband Dielectric Spectroscopy. Macromolecules, 40(8), 2773-2781. doi:10.1021/ma070016aSabater i Serra, R., Escobar Ivirico, J. L., Meseguer Dueñas, J. M., Balado, A. A., Gómez Ribelles, J. L., & Salmerón Sánchez, M. (2009). Segmental dynamics in poly(ε-caprolactone)/poly(L-lactide) copolymer networks. Journal of Polymer Science Part B: Polymer Physics, 47(2), 183-193. doi:10.1002/polb.21629Nogales, A., Sanz, A., Ezquerra, T. A., Quintana, R., & Muñoz-Guerra, S. (2006). Molecular dynamics of poly(butylene tert-butyl isophthalate) and its copolymers with poly(butylene terephthalate) as revealed by broadband dielectric spectroscopy. Polymer, 47(20), 7078-7084. doi:10.1016/j.polymer.2006.07.044Sanz, A., Nogales, A., Ezquerra, T. A., Lotti, N., & Finelli, L. (2004). Cooperativity of theβ-relaxations in aromatic polymers. Physical Review E, 70(2). doi:10.1103/physreve.70.021502Johari, G. P., & Goldstein, M. (1970). Viscous Liquids and the Glass Transition. II. Secondary Relaxations in Glasses of Rigid Molecules. The Journal of Chemical Physics, 53(6), 2372-2388. doi:10.1063/1.1674335Johari, G. P., & Smyth, C. P. (1972). Dielectric Relaxation of Rigid Molecules in Supercooled Decalin. The Journal of Chemical Physics, 56(9), 4411-4418. doi:10.1063/1.1677882Paluch, M., Pawlus, S., Hensel-Bielowka, S., Kaminska, E., Prevosto, D., Capaccioli, S., … Ngai, K. L. (2005). Two secondary modes in decahydroisoquinoline: Which one is the true Johari Goldstein process? The Journal of Chemical Physics, 122(23), 234506. doi:10.1063/1.1931669Ngai, K. L. (1998). Relation between some secondary relaxations and the α relaxations in glass-forming materials according to the coupling model. The Journal of Chemical Physics, 109(16), 6982-6994. doi:10.1063/1.477334Ngai, K. L., & Paluch, M. (2004). Classification of secondary relaxation in glass-formers based on dynamic properties. The Journal of Chemical Physics, 120(2), 857-873. doi:10.1063/1.1630295Casalini, R., Ngai, K. L., & Roland, C. M. (2003). Connection between the high-frequency crossover of the temperature dependence of the relaxation time and the change of intermolecular coupling in glass-forming liquids. Physical Review B, 68(1). doi:10.1103/physrevb.68.014201Ngai, K. L., & Tsang, K. Y. (1999). Similarity of relaxation in supercooled liquids and interacting arrays of oscillators. Physical Review E, 60(4), 4511-4517. doi:10.1103/physreve.60.4511Donth, E. (1996). Characteristic length of the glass transition. Journal of Polymer Science Part B: Polymer Physics, 34(17), 2881-2892. doi:10.1002/(sici)1099-0488(199612)34:173.0.co;2-uWilliams, G. (s. f.). Molecular aspects of multiple dielectric relaxation processes in solid polymers. Electric Phenomena in Polymer Science, 59-92. doi:10.1007/3-540-09456-3_3Ngai, K., & Capaccioli, S. (2004). Relation between the activation energy of the Johari-Goldstein β relaxation and T_{g} of glass formers. Physical Review E, 69(3). doi:10.1103/physreve.69.031501Casalini, R., & Roland, C. M. (2003). Pressure Evolution of the Excess Wing in a Type-BGlass Former. Physical Review Letters, 91(1). doi:10.1103/physrevlett.91.015702Redondo-Foj, B., Carsí, M., Ortiz-Serna, P., Sanchis, M. J., García, F., & García, J. M. (2013). Relaxational study of poly(vinylpyrrolidone-co-butyl acrylate) membrane by dielectric and dynamic mechanical spectroscopy. Journal of Physics D: Applied Physics, 46(29), 295304. doi:10.1088/0022-3727/46/29/295304Redondo-Foj, B., Carsí, M., Ortiz-Serna, P., Sanchis, M. J., Vallejos, S., García, F., & García, J. M. (2014). Effect of the Dipole–Dipole Interactions in the Molecular Dynamics of Poly(vinylpyrrolidone)-Based Copolymers. Macromolecules, 47(15), 5334-5346. doi:10.1021/ma500800aBershtein, V. A., Egorova, L. M., Yakushev, P. N., Pissis, P., Sysel, P., & Brozova, L. (2002). Molecular dynamics in nanostructured polyimide-silica hybrid materials and their thermal stability. Journal of Polymer Science Part B: Polymer Physics, 40(10), 1056-1069. doi:10.1002/polb.10162Alves, N. M., Gómez Ribelles, J. L., & Mano, J. F. (2005). Enthalpy relaxation studies in polymethyl methacrylate networks with different crosslinking degrees. Polymer, 46(2), 491-504. doi:10.1016/j.polymer.2004.11.016Scott, T. F., Cook, W. D., & Forsythe, J. S. (2002). Kinetics and network structure of thermally cured vinyl ester resins. European Polymer Journal, 38(4), 705-716. doi:10.1016/s0014-3057(01)00244-0Wagner, K. W. (1914). Erklärung der dielektrischen Nachwirkungsvorgänge auf Grund Maxwellscher Vorstellungen. Archiv für Elektrotechnik, 2(9), 371-387. doi:10.1007/bf01657322Hodge, I. M., Ngai, K. L., & Moynihan, C. T. (2005). Comments on the electric modulus function. Journal of Non-Crystalline Solids, 351(2), 104-115. doi:10.1016/j.jnoncrysol.2004.07.089Williams, G., & Watts, D. C. (1970). Non-symmetrical dielectric relaxation behaviour arising from a simple empirical decay function. Transactions of the Faraday Society, 66, 80. doi:10.1039/tf9706600080Williams, G., Watts, D. C., Dev, S. B., & North, A. M. (1971). Further considerations of non symmetrical dielectric relaxation behaviour arising from a simple empirical decay function. Transactions of the Faraday Society, 67, 1323. doi:10.1039/tf9716701323Havriliak, S., & Negami, S. (1967). A complex plane representation of dielectric and mechanical relaxation processes in some polymers. Polymer, 8, 161-210. doi:10.1016/0032-3861(67)90021-3Havriliak, S., & Negami, S. (2007). A complex plane analysis of α-dispersions in some polymer systems. Journal of Polymer Science Part C: Polymer Symposia, 14(1), 99-117. doi:10.1002/polc.5070140111S. Havriliak and S.Negami , Dielectric and Mechanical Relaxation in Materials , Hanser , Munich , 1997 , p. 57Glatz-Reichenbach, J. K. W., Sorriero, L., & Fitzgerald, J. J. (1994). Influence of Crosslinking on the Molecular Relaxation of an Amorphous Copolymer Near Its Glass-Transition Temperature. Macromolecules, 27(6), 1338-1343. doi:10.1021/ma00084a010Cole, K. S., & Cole, R. H. (1941). Dispersion and Absorption in Dielectrics I. Alternating Current Characteristics. The Journal of Chemical Physics, 9(4), 341-351. doi:10.1063/1.1750906Boyd, R. H. (1985). Relaxation processes in crystalline polymers: experimental behaviour — a review. Polymer, 26(3), 323-347. doi:10.1016/0032-3861(85)90192-2Laredo, E., Grimau, M., Sánchez, F., & Bello, A. (2003). Water Absorption Effect on the Dynamic Properties of Nylon-6 by Dielectric Spectroscopy. Macromolecules, 36(26), 9840-9850. doi:10.1021/ma034954wHuo, P., & Cebe, P. (1992). Dielectric relaxation of poly(phenylene sulfide) containing a fraction of rigid amorphous phase. Journal of Polymer Science Part B: Polymer Physics, 30(3), 239-250. doi:10.1002/polb.1992.090300303Noda, N., Lee, Y.-H., Bur, A. J., Prabhu, V. M., Snyder, C. R., Roth, S. C., & McBrearty, M. (2005). Dielectric properties of nylon 6/clay nanocomposites from on-line process monitoring and off-line measurements. Polymer, 46(18), 7201-7217. doi:10.1016/j.polymer.2005.06.046Ryabov, Y. E., Nuriel, H., Marom, G., & Feldman, Y. (2002). Relaxation peak broadening and polymer chain dynamics in aramid-fiber-reinforced nylon-66 microcomposites. Journal of Polymer Science Part B: Polymer Physics, 41(3), 217-223. doi:10.1002/polb.10384Janik, P., Paluch, M., Ziolo, J., Sulkowski, W., & Nikiel, L. (2001). Low-frequency dielectric relaxation in rubber. Physical Review E, 64(4). doi:10.1103/physreve.64.042502Feldman, Y., Puzenko, A., & Ryabov, Y. (2002). Non-Debye dielectric relaxation in complex materials. Chemical Physics, 284(1-2), 139-168. doi:10.1016/s0301-0104(02)00545-1Ortiz-Serna, P., Díaz-Calleja, R., Sanchis, M. J., Floudas, G., Nunes, R. C., Martins, A. F., & Visconte, L. L. (2010). Dynamics of Natural Rubber as a Function of Frequency, Temperature, and Pressure. A Dielectric Spectroscopy Investigation. Macromolecules, 43(11), 5094-5102. doi:10.1021/ma1004869Ortiz-Serna, P., Díaz-Calleja, R., Sanchis, M. J., Riande, E., Nunes, R., Martins, A., & Visconte, L. (2011). Dielectric spectroscopy of natural rubber-cellulose II nanocomposites. Journal of Non-Crystalline Solids, 357(2), 598-604. doi:10.1016/j.jnoncrysol.2010.06.044E. Riande and R.Díaz-Calleja , Electrical Properties of Polymers , Marcel Dekker , New York , 2004Fulcher, G. S. (1925). ANALYSIS OF RECENT MEASUREMENTS OF THE VISCOSITY OF GLASSES. Journal of the American Ceramic Society, 8(6), 339-355. doi:10.1111/j.1151-2916.1925.tb16731.xTammann, G., & Hesse, W. (1926). Die Abhängigkeit der Viscosität von der Temperatur bie unterkühlten Flüssigkeiten. Zeitschrift für anorganische und allgemeine Chemie, 156(1), 245-257. doi:10.1002/zaac.19261560121Lunkenheimer, P., Schneider, U., Brand, R., & Loid, A. (2000). Glassy dynamics. Contemporary Physics, 41(1), 15-36. doi:10.1080/001075100181259Angell, C. A. (1995). Formation of Glasses from Liquids and Biopolymers. Science, 267(5206), 1924-1935. doi:10.1126/science.267.5206.1924C. A. Angell , Complex Behavior of Glassy Systems; Proceedings of the XIV Sitges Conference , Sitges, Barcelona, Spain, 1996F. J. Bermejo , H. E.Fischer , M. A.Ramos , A.de Andrés , J.Dawidowski and V.Fayos , in Complex Behaviour of Glassy Systems , Springer Lecture Notes in Physics , ed. M. Rubí and C. Pérez-Vicente , Springer , Berlin-Heidelberg , 1997Böhmer, R., Ngai, K. L., Angell, C. A., & Plazek, D. J. (1993). Nonexponential relaxations in strong and fragile glass formers. The Journal of Chemical Physics, 99(5), 4201-4209. doi:10.1063/1.466117Böhmer, R., & Angell, C. A. (1992). Correlations of the nonexponentiality and state dependence of mechanical relaxations with bond connectivity in Ge-As-Se supercooled liquids. Physical Review B, 45(17), 10091-10094. doi:10.1103/physrevb.45.10091Böhmer, R., & Angell, C. A. (1993). Elastic and viscoelastic properties of amorphous selenium and identification of the phase transition between ring and chain structures. Physical Review B, 48(9), 5857-5864. doi:10.1103/physrevb.48.5857Merino, E. G., Atlas, S., Raihane, M., Belfkira, A., Lahcini, M., Hult, A., … Correia, N. T. (2011). Molecular dynamics of poly(ATRIF) homopolymer and poly(AN-co-ATRIF) copolymer investigated by dielectric relaxation spectroscopy. European Polymer Journal, 47(7), 1429-1446. doi:10.1016/j.eurpolymj.2011.04.006Angell, C. . (1991). Relaxation in liquids, polymers and plastic crystals — strong/fragile patterns and problems. Journal of Non-Crystalline Solids, 131-133, 13-31. doi:10.1016/0022-3093(91)90266-9Qin, Q., & McKenna, G. B. (2006). Correlation between dynamic fragility and glass transition temperature for different classes of glass forming liquids. Journal of Non-Crystalline Solids, 352(28-29), 2977-2985. doi:10.1016/j.jnoncrysol.2006.04.014Kohlrausch, R. (1854). Theorie des elektrischen Rückstandes in der Leidener Flasche. Annalen der Physik und Chemie, 167(2), 179-214. doi:10.1002/andp.18541670203Zorn, R. (1999). Applicability of distribution functions for the Havriliak-Negami spectral function. Journal of Polymer Science Part B: Polymer Physics, 37(10), 1043-1044. doi:10.1002/(sici)1099-0488(19990515)37:103.0.co;2-hNgai, K. L., & Roland, C. M. (1993). Intermolecular cooperativity and the temperature dependence of segmental relaxation in semicrystalline polymers. Macromolecules, 26(11), 2688-2690. doi:10.1021/ma00063a008K. L. Ngai , Relaxation and diffusion in complex systems , Springer , Berlin , 2011Ikeda, M., & Aniya, M. (2010). Correlation between fragility and cooperativity in bulk metallic glass-forming liquids. Intermetallics, 18(10), 1796-1799. doi:10.1016/j.intermet.2010.01.009Patkowski, A., Paluch, M., & Gapiński, J. (2003). Relationship between T0, Tg and their pressure dependence for supercooled liquids. Journal of Non-Crystalline Solids, 330(1-3), 259-263. doi:10.1016/j.jnoncrysol.2003.09.002Delpouve, N., Delbreilh, L., Stoclet, G., Saiter, A., & Dargent, E. (2014). Structural Dependence of the Molecular Mobility in the Amorphous Fractions of Polylactide. Macromolecules, 47(15), 5186-5197. doi:10.1021/ma500839

Molecular Dynamics of Functional Azide-Containing Acrylic Films

A report on the syntheses, thermal, mechanical and dielectric characterizations of two novel polymeric acrylic materials with azide groups in their pendant structures is presented. Having the same general structure, these polymers differ in length of oxyethylene units in the pendant chain [-CONH-CH2CH2-(O-CH2CH2)nN3], where n is 1 (poly(N-(2-(2-azidoethoxy)ethyl)methacrylamide), PAzMa1) or 2 (poly(N-2-(2-(2-azidoethoxy)ethoxy)ethyl)methacrylamide), PAzMa2), leading with changes in their dynamics. As the thermal decomposition of the azide group is observed above 100 °C, dielectric analysis was carried out in the temperature range of −120 °C to 100 °C. Dielectric spectra of both polymers exhibit in the glassy state two relaxations labelled in increasing order of temperature as γ- and β-processes, respectively. At high temperatures and low frequencies, the spectra are dominated by ohmic conductivity and interfacial polarization effects. Both, dipolar and conductive processes were characterized by using different models. Comparison of the dielectric activity obtained for PAzMa1 and PAzMa2 with those reported for crosslinked poly(2-ethoxyethylmethacrylate) (CEOEMA) was performed. The analysis of the length of oxyethylene pendant chain and the effect of the methacrylate or methacrylamide nature on the dynamic mobility was analysed

Electrical conductivity of natural rubber cellulose II nanocomposites

[EN] Nanocomposite materials obtained from natural rubber (NR) reinforced with different amounts of cellulose II (cell) nanoparticles (in the range of 0 to 30 phr) are studied by dielectric spectroscopy (DS) in a broad temperature range (¿150 to 150 °C). For comparative purposes, the pure materials, NR and cell, are also investigated. An analysis of the cell content effect on the conductive properties of the nanocomposites was carried out. The dielectric spectra exhibit conductivity phenomena at low frequencies and high temperatures: Maxwell¿Wagner¿ Sillars (MWS) and electrode polarization (EP) conductive processes were observed in the nanocomposite samples.We thank Professor Regina Nunes of the Instituto de Macromoleculas Eloisa Mano (Universidade Federal do Rio de Janeiro) for providing us the NR and NR-cell samples. This work was financially supported by DGCYT through grant MAT2012-33483.Ortiz Serna, MP.; Carsí Rosique, M.; Redondo Foj, MB.; Sanchis Sánchez, MJ. (2014). Electrical conductivity of natural rubber cellulose II nanocomposites. Journal of Non-Crystalline Solids. 405:180-187. doi:10.1016/j.jnoncrysol.2014.09.026S18018740

Theoretical modelling and experimental results of electromechanical actuation of an elastomer

Electromechanical actuation is a growing field of research today both for applications or theoretical modelling. The interaction between electric and mechanical constraints has been used for electromechanic actuators or generators based on elastomers. From a theoretical point of view, many recent works have been focused on uniaxial or biaxial stretching of elastomer plates with compliant electrodes. Free stretching or pre-strained samples have been theoretically modelled, mainly by neo-Hookean equations. In this work, we present theoretical and experimental results of electromechanic actuation of an elastomer (the widely used 3M VHB4910, an acrylic foam) in a pre-strained case and a free case. Experimental characterization of the material shows that the Ogden model gives the best accurate fitting of mechanical properties. Thus, a theoretical development based on this model is carried out in order to obtain the curves describing the electromechanical behaviour of the material. The mechanical instability related to wrinkling of the material is theoretically calculated and experimentally verified.Díaz Calleja, R.; Llovera Segovia, P.; Jorge Domínguez, J.; Carsí Rosique, M.; Quijano Lopez, A. (2013). Theoretical modelling and experimental results of electromechanical actuation of an elastomer. Journal of Physics D: Applied Physics. 46(23):1-10. doi:10.1088/0022-3727/46/23/235305S110462

Conductivity and Time-Temperature Correspondence in Polar Viscoelastic Liquids

This work is focused on the conductivity study of viscoelastic liquids, taking as a model poly(2,3-dimethoxybenzyl methacrylate). Each isotherm, displaying the conductivity in the frequency domain, shows a plateau in the low frequency region, representing the dc conductivity. The covered frequency range by the plateau increases with the temperature. The frequency corresponding to the end of the plateau, ωc, marks the onset of the ac conductivity, which correspond in increasing order of frequency to Maxwell− Wagner−Sillars, glass−rubber transition and secondary relaxations. The contributions of the relaxation processes to the ac conductivity in the wholly frequencies range were analyzed. The time−temperature correspondence principle holds for the reduced ac conductivity. However, this principle does not hold for the components of the complex dielectric permittivity due, among other things, to the different temperature dependences of each dipolar relaxation processes. Analogueies and differences between the conductivity behavior of viscoelastic liquids and disordered inorganic solids are discussed.This work was financially supported by the DGCYT and CAM through the Grant MAT2012-33483. This work is dedicated in memoriam of Professor Emeritus Evaristo Riande in recognition of his contribution to polymer science.Carsí Rosique, M.; Sanchis Sánchez, MJ.; Ortiz Serna, MP.; Redondo Foj, MB.; Díaz Calleja, R.; Riande, E. (2013). Conductivity and Time-Temperature Correspondence in Polar Viscoelastic Liquids. Macromolecules. 46(8):3167-3175. https://doi.org/10.1021/ma400224xS3167317546