Compatible blends of thermoplastic starch and hydrolyzed ethylene-vinyl acetate copolymers

AbstractEthylene-vinyl acetate copolymer (EVA) with 19% of vinyl acetate and its derivatives modified by hydrolysis of 50 and 100% of the initial vinyl acetate groups were used to produce blends with thermoplastic starch (TPS) plasticized with 30wt% glycerol. The blends were characterized by Fourier transform infrared spectroscopy, scanning electron microscopy, X-ray diffraction, water absorption, stress–strain mechanical tests, dynamic mechanical analysis and thermogravimetric analysis. In contrast to the blends with unmodified EVA, those made with hydrolyzed EVA were compatible, as demonstrated by the brittle fracture surface analysis and the results of thermal and mechanical tests. The mechanical characteristics and water absorption of the TPS were improved even with a small addition (2.5wt%) of hydrolyzed EVA. The glass transition temperature rose with the degree of hydrolysis of EVA by 40 and 50°, for the EVA with 50 and 100% hydrolysis, respectively. The addition of hydrolyzed EVA proved to be an interesting approach to improving TPS properties, even when very small quantities were used, such as 2.5wt%

A Morphological View Of The Sodium 4,4′-distyrylbiphenyl Sulfonate Fluorescent Brightness Distribution On Regenerated Cellulose Fibers

Evidence of the sorption of the whitening agent sodium 4,4′- distyrylbiphenyl sulfonate in the presence of the anionic surfactant sodium dodecylsulfate or the cationic surfactant dodecyl trimethyl ammonium chloride on regenerated cellulose fibers is given by several microscopy techniques. Scanning electron microscopy provided images of the cylindrical fibers with dimensions of 3.5 cm (length) and 13.3 lm (thickness), with empty cores of 1 μm diameter and a smooth surface. Atomic force microscopy showed a fiber surface with disoriented nanometric domains using both tapping-mode height and phase image modes. Atomic force microscopy also showed that the whitening agent and surfactant molecules were sorbed onto the fiber surface, in agreement with the adsolubilization sorption model. Transmission electron microscopy showed fibers with nanometric parallel cylinders, surrounded by holes where the fluorescent whitening molecules accumulated. On the basis of these techniques, we conclude that the sorption process occurs preferentially on the fiber surface in contact with the water solution, and under saturated conditions, the whitening agent penetrates into the pores and are simultaneously sorbed on the pore walls bulk, forming molecular aggregates. © 2010 Wiley Periodicals, Inc.118423212327Pielesz, A., Wesełucha-Birczyńska, A., Freeman, H.S., Wlochowicz, A., (2005) Cellulose, 12, p. 497Kreze, T., Strand, S., Stana-Kleinschek, K., Ribitsch, V., (2001) Mater. Res. Innov., 4, p. 107Abu-Rous, M., Ingolic, E., Schuster, K.C., (2006) Cellulose, 13, p. 411Jakob, H.F., Fengel, D., Tschegg, S.E., Fratzl, P., (1995) Macromolecules, 28, p. 8782Há, M.A., Apperley, D.C., Evans, B.W., Huxham, M., Jardine, W.G., Vietor, R.J., Reis, D., Jarvis, M.C., (1998) Plant. J., 16, p. 183Muller, M., Hori, R., Itoh, T., Sugiyama, J., (2002) Biomacromolecules, 3, p. 182Nigmatullin, R., Lovitt, R., Wright, C., Linder, M., Nakari-Setala, T., Gama, A., (2004) Colloids Surf B. Biointerfaces, 35, p. 125Zugenmaier, P., (2001) Prog. Polym. Sci., 26, p. 1341Krassig, H., (1978) Tappi, 61, p. 93Kotek, R., (2007) Handbook of Fiber Chemistry, p. 667. , 3rd ed.Lewin, M., Ed.CRC Press: New YorkMikhailov, N.V., Gorbacheva, V.O., Krasova, I.I., Milkova, L.P., Bochkina, V.S., Nikolaeva, N.S., (1972) Fiber Chem., 2, p. 619Iamazaki, E.T., Atvars, T.D.Z., (2007) Langmuir, 23, p. 12886Iamazaki, E.T., Atvars, T.D.Z., (2006) Langmuir, 22, p. 9866Stana-Kleinschek, K., Strand, S., Ribitsch, V., (1999) Polym. Eng. Sci., 39, p. 1412Stana-Kleinschek, K., Pohar, C., Ribitsch, V., (1995) Colloid Polym. Sci., 273, p. 1174Yamaki, S.B., Barros, D.S., Garcia, C.M., Socoloski, P., Oliveira, O.N., Atvars, T.D.Z., (2005) Langmuir, 21, p. 5414Kim, J., Yun, S., Ounaies, Z., (2006) Macromolecules, 39, p. 4202Iamazaki, E.T., Atvars, T.D.Z., (2008) Dyes Pigm, 76, p. 669Aloulou, F., Boufi, S., Belgacem, N., Gandini, A., (2004) Colloid Polym. Sci., 283, p. 344Alila, S., Boufi, S., Belgacem, M.N., Beneventi, D., (2005) Langmuir, 21, p. 8106O'Haver, J.H., Harwell, J.H., In surfactant adsorption and surface solubilization (1995) ACS Symposium Series, 615, p. 49. , Sharma, R., Ed.American Chemical Society: WashingtonTalhavini, M., Atvars, T.D.Z., Schurr, O., Weiss, R.G., (1998) Polymer., 39, p. 322