Photonic crystals in biology - NanoTR-VI

PPPPPPPoster Session, Thursday, June 17Theme F686 - N1123Evaluation of Permeability of Masterbatch-Based PA6/nanoclay Composite Films11UMohammad FasihiUP0F P*and Mohammad Reza Abolghasemi0TPTechnology of Polymer Research Group, Iranian Academic Center for Education, Culture and Research (ACECR), Branch of AmirkabirUniversity of Technology, Tehran, Iran,Abstract-This study focuses on the effect of the nanoclay masterbatch on the extent of exfoliation and barrier properties of PA6/organoclaynanocomposite films. Gas permeability through nanocomposite films decreased significantly just by loading a small amount of nanoclay.Theoretical models fit the experimental data appropriately.Over the last decades, a great deal of researches have beendevoted to the different fields of polymer-layered silicatenanocomposites which have shown promising improvements[1-3]in properties, at low filler volume fraction.POne of the great attractive applications of polymer-layeredsilicate nanocomposites is the field of packaging. Thereduction of oxygen permeability is of crucial importancesince oxygen as an atmospheric component which promotesthe spoilage mechanism of food. Incorporating layered silicateinto the polymeric matrix, ordinarily, improves gas barrierproperties of the polymer by reducing the volume available forgas transport as well as making a more tortuous path for[4-6]penetrant molecules. PThe current study examined the effect of nanoclaydispersion by using particulate nanoclay and nanoclaymasterbatch, on morphology and oxygen permeability ofpolyamide-6 /layered silicate nanocomposite films bearingdifferent concentrations of nanoclay, as a potential candidatefor good packaging applications. Furthermore, thepermeability data has also been compared to the theoreticalmodels.XRD results showed flat diffraction profile and the absenceof any basal reflections indicated that the ordered layers ofnanoclays in the nanocomposites have been disrupted.With regards to the crystalline structure, all films exhibited aostrong reflection at 21.5P distinguished t crystal form which showed that the loading of nanoclay didnot alter crystal structures in thin films.Although XRD scan results suggested only a low degree ofintercalation, the morphology observed with TEM indicatedthe presence of both intercalated and exfoliated structures. Thegeneral impression obtained from TEM was that the use ofmasterbatch builds up a higher degree of exfoliation thatconfirms the better properties of masterbatch-basednanocomposites. The maximum aspect ratio of the layers asdeduced from the TEM micrographs was about 210 in allsamples.Oxygen permeability was reduced by a factor of 4 over thepure polyamide by incorporation of 3 wt% nanoclay. As thenanoclay loading was increased to 7 wt%, only a slightimprovement in permeation resistance was observed.Several studies on modeling the barrier properties ofpolymer nanocomposite have been performed based on the[7],tortuous pathway concept by Cussler.P Fredrickson and[8,9]Gusev et al.P Bharadwaj improved Nielsen’s model by[6]simply introducing a new order parameter. P Another model[10]called NG model was developed by Ghasemi et al.PPThetheoretical models fit the experimental data properly.In summery, we showed improvements in oxygen barrierand mechanical properties by increasing the silicate content. Inparticular, nanocomposite films based on masterbatchexhibited the best performances. XRD scans and TEMmicrographs collectively demonstrated the good dispersionand orientation of silicate platelets inside the matrix, as well asthe possible presence of polymer-clay interactions. Thetheoretical model fitted the experimental data very well.Figure 1. TEM images of specimens (a) particulate nanoclay-basedfilms (b), (c) masterbatched-based films*Corresponding author:mohammadreza.abolghasemi@gmail.com[1] Ke, Y., Long, C., Qi, Z, J. Appl. Polym. Sci. 1999, 71, 1139-1146.[2] Becker, O., Cheng, Y., Varley, J. R., Simon, G. P,Macromolecules 2003, 36, 1616-1625.[3] Alexandre, M., Dubois, P. Mater. Sci. Eng. 2000, 28, 1-63.[4] H. Yamamoto, Y. Mi, S.A. Stern, J. Polym. Sci., Part B:Polym. Phys. 1990, 28, 2291-2304.[5] Fornes, T. D., Paul, D. R., Polymer 2003, 44, 4993-5013.[6] Liu, L., Qi, Z., Zhu, X. J. Appl. Polym. Sci. 1999, 71, 1133-1138.[7] Yang, W.H. Smyrl, E.L. Cussler, J. Membr. Sci. 2004, 231,1-12.[8] G. H. Fredrickson, J. Bicerano, J. Chem. Phys. 1999, 110,2181-2188.[9] A.Gusev, H.R. Lusti, Adv. Mat., 2001, 13, 1641-1643.[10] E. Ghasemi, A. H. Navarchian, “Modeling the Effects ofSilicate Layer Orientation on Barrier Properties of Polymer/ClayNanocomposites”, proceeding of 9th International Seminar onPolymer Science and Technology (3TISPST3T 2009), Tehran, Iran.6th Nanoscience and Nanotechnology Conference, zmir, 2010 714