Document Type : Research Paper

Abstract

The present study developed an improved nanocomposite based on polylactic acid (PLA) biopolymer. The structural properties of PLA nanocomposites of clay and cellulose nanoparticles were evaluated for level and water vapor permeability (WVP) using thermal and casting methods. Thermal tests (DSC) showed that pure PLA had a glass transition point (Tg) of 53.83, a melting point (Tm) of 153.95°C and crystallization (x%) of 41.36%. With the incorporation of clay nanoparticles, Tg and x% increased, while Tm showed no significant change. The micro-crystal cellulose (MCC) nanoparticles were not compatible with the polymer matrix, so there was no effect on the thermal properties. WVP results showed that pure PLA had high permeability; the addition of clay nanoparticles strongly decreased WVP. The sample with 7% clay had a permeability of 0.92×10-11 g/m.S.Pa. WVP of the film increased significantly as a result of the hydrophilic nature of the MCC. The SEM images of the samples confirmed the results.

Keywords

Anon. 1995. Standard Test Methods for Water Vapor Transmission of Materials. ASTM E96-05. American Society for Testing and Materials. Philadelphia, PA.
Arora, A. and Padua, G. W. 2010. Review: Nanocomposites in food packaging. J.  Food Sci. 75 (1): 43-49.
Auras, R., Harte, B., Selke, S. and Hernandez, R. 2003. Mechanical, physical, and barrier properties of poly (lactide) films. J. Plas. Film Sheet. 19, 123-35.
Balakrishnan, H., Hassan, A., Wahit, M. U., Yussuf, A. A. and Razak, S. B. A. 2010. Novel toughened polylactic acid nanocomposite: Mechanical, thermal and morphological properties. Mater. Design. 31, 3289-3298.
Bharadwaj, R. K. 2001. Modeling the barrier properties of polymer-layered silicate nanocomposites. Macromol. 34, 9189-92.
Bissot, T. C. 1989. Barrier Polymers and Structures. ACS Symposium Series. American Chemical Society. Washington, D. C.
Boredes, P., Pollet, E. and Averous, L. 2009. Nano-biocomposites: biodegradable polyester/nanoclay systems. Prog. Polym. Sci. 34, 125-155.
Cabedo, L., Feijoo, J. L., Villanueva, M. P., Lagaron, J. M. and Gimenez, E. 2006. Optimization of biodegradable nanocomposites based on PLA/PCL blends for food packaging applications. Macromol. Symp. 233, 191-197.
Chiang, M. F., Chen, E. C. and Wu, T. M. 2012. Preparation, mechanical properties and thermal stability of poly (L-lactide)/γ-polyglutamate-modified layered double hydroxide nanocomposites. Polym. Degrad. Stabil. 97, 995-1001.
Chiellini, E., Chiellini, F. and Cinelli, P. 2002. Polymers from Renewable Sources. In: Scott, G. (Ed.) Degradable Polymers. Luwer Academic Pub. U. K. 163-234.
Cussler, E. L., Highes, S. E., Ward, W. J. and Aris, R. 1998. Barrier membranes. J.  Membrane Sci.
38, 161-174.
Drumright, R. E., Gruber, P. R. and Henton, D. E. 2000. Poly lactic acid technology. Adv. Mater.
 12, 1841-1846.
Fischer, E. W., Sterzel, H. J. and Wegner, G. 1973. Investigation of the structure of solution grown
crystals of lactide copolymers by means of chemicals reactions. Kolloid Z. Z. Polym. 251(11):
980-982.
Fukushima, K., Murariu, M., Camino, G. and Dubois, P. 2010. Effect of expanded graphite/layered-silicate clay on thermal, mechanical and fire retardant properties of poly (lactic acid). Polym. Degrad. Stabil. 95, 1063-1076.
Garlotta, D. 2001. A literature review of poly (lactic acid). J. Polym. Environ. 9(2): 63-84.
Harada, M., Ohya, T., Iida, K., Hayashi, H., Hirano, K. and Fukuda, H. 2007. Increased impact strength of biodegradable poly (lactic acid)/poly (butylenes succinate) blend composites by using isocyanate as a reactive processing agent. J. Appl. Polym. Sci. 106, 1813-1820.
Hubbe, M. A., Rojas, O. J., Lucia, L. A. and Sain, M. 2008. Cellulosic nanocomposites: a review. Bioresources. 3(3): 929-980. 
Kubies, D., Scudla, J., Puffr, R., Sikora, A., Baldrian, J., Kovářová, J., Šlouf, M. and Rypáček, F. 2006. Structure and mechanical properties of poly (L-lactide)/layered silicate nanocomposites. Eur. Polym. J. 42. 888-899.
Lewitus, D., McCarthy, S., Ophir, A. and Kenig, S. 2006. The effect of nanoclays on the properties of PLLA-modified polymers, Part 1: mechanical and thermal properties. J. Polym. Environ.
14(2): 171-177.
Lu, X., Lv, X., Sun, Z. and Zheng, Y. 2008. Nanocomposites of poly (L-lactide) and surfacegrafted TiO2 nanoparticles: synthesis and characterization. Eur. Polym. J. 44(8): 2476-2481.
Nam, J. Y., Sinha Ray, S. and Okamoto, M. 2003. Crystallization behavior and morphology of biodegradable polylactide/layered silicate nanocomposite. Macromol. 36, 7126-7131.
Okubo, K., Fujii, T. and Thostenson, E. T. 2009. Multi-scale hybrid biocomposite: processing and mechanical characterization of bamboo fiber reinforced PLA with microfibrillated cellulose. Composites: Part A. 40, 469-475.
Petersson, L. and Oksman, K. 2006. Biopolymer based nanocomposites: comparing layered silicates and microcrystalline cellulose as nanoreinforcement. Compos. Sci. Technol. 66, 2187-2196.
Petersson, L., Oksman, K. and Mathew, A. P. 2006. Using Maleic Anhydride Grafted Poly (lactic acid) as a Compatibilizer in Poly (lactic acid)/Layered-Silicate Nanocomposites. J. Appl. Polym. Sci. 102,
1852-1862.
Platt, D. 2006. Biodegradable Polymers-Market Report. Smithers Rapra Limited. Shawbury, Shrewsbury, Shropshire UK.
Rhim, J. W., Hong, S. I. and Ha, C. S. 2009. Tensile, water vapor barrier and antimicrobial properties of PLA/nanoclay composite films. LWT- Food Sci. Technol. 42, 612-617.
Shyang, C. W. and Kuen, L. S. 2008. Flexural, morphological and thermal properties of polylactic acid/organo-montmorillonite nanocomposites. Polym. Composites. 16(4): 263-270.
Sinha Ray, S. and Okamoto, M. 2003. Polymer/layered silicate nanocomposites: a review from preparation to processing. Prog. Polym. Sci. 28, 1539-1641.
Sinha Ray, S., Okamoto, K., Yamada, K. and Okamoto, M. 2002a. Novel porous ceramic material via burning of polylactide/layered silicate nanocomposite. Nano Letters. 2, 423-426.
Sinha Ray, S., Yamada, K., Okamoto, M. and Ueda, K. 2002b. New polylactide/layered silicate nanocomposite: a novel biodegradable material. Nano Letters. 2, 1093-1096.
Sinha Ray, S., Vaudreuil, S., Maazouz, A. and Bousmina, M. 2006. Dispersion of multi-walled carbon nanotubes in biodegradable poly (butylene succinate) matrix. J. Nanosci. Nanotechnol. 6 (7):
2191-2195.
Sinha Ray, S., Maiti, P., Okamoto, M., Yamada, K. and Ueda, K. 2002c. New polylactide/layered silicate nanocomposites. 1. Preparation, characterization and properties. Macromol. 35, 3104-3110.
Sinha Ray, S., Yamada, K., Ogami, A., Okamoto, M. and Ueda, K. 2002d. New polylactide layered silicate nanocomposite: 2. Nanoscale control of multiple properties. Macromol. Rapid Comm. 23, 493-497.
Sinha Ray, S., Yamada, K., Okamoto, M., Ogami, A. and Ueda, K. 2003. New polylactide/layered silicate nanocomposites. 3. High performance biodegradable materials. Chem. Mater. 15(7): 1456-1465.
Sorrentino, A., Gorrasi, G. and Vittoria, V. 2007. Potential perspectives of bionanocomposites for food packaging applications. Trends Food Sci. Tech. 18, 84-95.
Tsuji, H., Steinbuchel, A. and Machessault, R. H. 2005. Biopolymers for Medical and Pharmaceutical Applications. WILEY-VCH Verlag GmbH & Co.
Vasconez, M. B., Flores, S. K., Campos, C. A., Alvarado, J. and Gerschenson, L. N. 2009. Antimicrobial activity and physical properties of chitosan-tapioca starch based edible films and coating. Food Res. Int. 42, 762-769.
Xu, J. Z., Chen, T., Yang, C. L., Li, Z. M., Mao, Y. M., Zeng, B. Q. and Hsiao, B. S. 2010. Isothermal crystallization of poly (L-lactide) induced by graphene nanosheets and carbon nanotubes: a comparative study. Macromol. 43(11): 5000-5008.
Yano, K., Usuki, A. and Okai, A. 1997. Synthesis and properties of polyimideclay hybrid films. J. Polym. Sci. Part A: Polymer Chemistry. 35, 2289-2294.