Photonic crystals in biology - NanoTR-VI

PPoster Session, Thursday, June 17Theme F686 - N11231Carrageenan Nanocomposite as Agrochemical Carrier1UGholam Reza MahdaviniaUP P*PDepartment of Chemistry, Faculty of Science, University of Maragheh, P.O. Box 55181-83111, Maragheh, Iran.Abstract- Nanocomposite hydrogels based on kappa-carrageenan were synthesized using sodium montmorillonite as nano-clay. Acrylamideand methylenebisacrylamide were used as monomer and crosslinker, respectively. The nanocomposite hydrogels were investigated by XRD,DSC, and SEM techniques. Sequsterene Fe as agrochemical was loaded into nanocomposite and release of this active agent was studiedaccording to Flick's law.Polymer hydrogels are three-dimensional hydrophilicnetworks that can absorb, swell, and retain aqueous fluids upto hundreds of times of their own weight [1]. The higherproduction cost and low gel strength of these hydrogels,however, restrict their application widely [2]. To improvethese limitations, inorganic compounds with low cost can beused. The introduction of inorganic fillers to a polymer matrixincreases its strength and stiffness properties. Because of theirwater retention property and subsequently, the slow release ofwater from swollen hydrogels, hydrogels with high swellingcapacity are of special interest as potential water retainersystems for agriculture fields [3,4]. Also, in the field ofagriculture, the slow release of water from the polymericmatrix opens another potential area of application that isrelated to load of agrochemicals into hydrogels. In the swollenhydrogels containing agrochemicals, not only the waterreleasing takes place, but also the agrochemical will bereleased together with water.In this work, we attempted to synthesis of nanocompositehydrogel using sodium montmorillonite and carrageenan asclay and biopolymer segment, respectively. In briefly, claywas dispersed in water and then carrageenan dissolved in claydispersed solution. After that, acrylamide andmethylenebisacrylamide were added as monomer andcrosslinker, respectively. Ammonium persulfate was added asinitiator. After synthesis, Sequsterene Fe was loaded intohydrogels and release of that was evaluated according toFlick's law.Nanocomposite hydrogels based on Carra were synthesizedusing solution polymerization. Na-MMt was used as clay.in nanocomposite and it can be concluded that the clay layersare completely exfoliated.The kinetic of sequsterene release from nanocompositehydrogels containing various content of clay was examinedusing Flick's law [5]:n(MRtR/MRR)=ktPwhere MRtR/MRR is the fraction released agrochemical at time t, kis the rate constant and n is the release exponent. The releaseis Fickian if n be 0.5. for n=0.5-1, the release will be non-Fickian. The curve of Ln(MRtR/MRR) against Ln(t) is illustrated inFigure 2. According to data from the Figure 2, the n values areshown in Table 1. The results show non-Fickian release fornanocomposites containing various content of clay.Ln(Mt/Mx)-3-2.5-2-1.5-1-0.50NC1NC2NC3NC4NC54 4.5 5 5.5 6Figure 2 Ln(MRtR/MRR) against Ln(t)Ln(t)Table 1. n values for nanocomposites containing various content ofclayNC1 NC2 NC3 NC4 NC5n 0.66 0.58 0.66 0.68 0.63Figure 1. XRD patterns of pristine clay and nanocomposite[1] R. Po, J. Macromo. Sc.-Re. Macromol Chem Phys C34(4), 607(1994).[2] W. Wang, A.Wang Carbohyd. Polym. 77, 891 (2009).[3] Z. Zhuo, R. Zhuo Eur. Polym. J. 37, 1913 (2001).[4] G. R. Mahdavinia, S. B. Mousavi, F. Karimi, G. B. Marandi, H.Garabaghi, S. Shahabvand Express Polym. Lett. 3, 279 (2009).[5] S. Swarnalatha, R. Gopi, A.G. Kumar, P.K. Selvi, G. Sekaran J.Mater. Sci: Mater. Med. 19, 3005 (2008).The XRD patterns of pristine clay and nanocomposites areshown in Figure 1. As shown in this figure, the XRD profile ofpristine Na-MMt shows a diffractive peak at 2=7.6corresponding to the distance of clay sheets with d spacing11.61 Aº. Stirring of clay for 24 h subsequently in situpolymerization of AAm in the presence of MBA crosslinkerleads to a nanocomposite hydrogel that the XRD profile of thishydrogel shown in Figure 1. No diffraction peak was observed6th Nanoscience and Nanotechnology Conference, zmir, 2010 774