Carbohydrate Polymers 127 (2015) 246–251 Contents lists available at ScienceDirect Carbohydrate Polymers j ourna l ho me pa g e: www.elsevier.com/locate/carbpol Physicochemical characterization of novel Schiff bases derived from developed bacterial cellulose 2,3-dialdehyde Sherif M.A.S. Keshk a,b,∗ , Ahmed M. Ramadan a,c , Samir Bondock a,d a King Khalid University, Faculty of Science, Chemistry Department, P.O. Box 9004, Abha 61413, Saudi Arabia b Ain Shams University, Institute of Environmental Studies and Research, Basic Science Department, Abbassia, Cairo 11566, Egypt c Alexandria University, Faculty of Science, Chemistry Department, Alexandria, Egypt d Chemistry Department, Faculty of Science, Mansoura University, Mansoura, Egypt a r t i c l e i n f o Article history: Received 28 January 2015 Received in revised form 16 March 2015 Accepted 20 March 2015 Available online 27 March 2015 Keywords: Bacterial cellulose Periodate oxidation Aldehyde content Schiff bases X-ray diffractogram a b s t r a c t The synthesis of two novel Schiff’s bases (cellulose-2,3-bis-[(4-methylene-amino)-benzene-sulfonamide] (5) & cellulose-2,3-bis-[(4-methylene-amino)-N-(thiazol-2-yl)-benzenesulfonamide] (6) via conden- sation reactions of periodate oxidized developed bacterial cellulose ODBC (2) with sulfa drugs [sulfanilamide (3) & sulfathiazole (4)] was reported. The physicochemical characterization of the con- densation products was performed using FTIR, 1 H NMR, 13 C NMR spectral analyses, X-ray diffraction and DTA. The ODBC exhibited the highest degree of oxidation based on the aldehyde group number percent- age (82.9%), which confirms the highest reactivity of developed bacterial cellulose [DBC (1)]. The X-ray diffractograms indicated an increase in the interplanar distance of the cellulose Schiff base (6) compared to ODBC (2) due to sulfathiazole (4) inclusion between ODBC (2) sheets corresponding to the ( 1 ¯ 10 ) plane. In addition, the aldehyde content of Schiff base (6) was (20.8%) much lower than that of Schiff base (5) (41.5%). These results confirmed the high affinity of sulfathiazole (4) to the ODBC (2) chain, and the substantial changes in the original properties of ODBC were due to these chemical modifications rather than the sulfanilamide (3). © 2015 Elsevier Ltd. All rights reserved. 1. Introduction Bacterial cellulose (BC) and its developed form (DBC) have potential application in a wide variety of industrial fields (Keshk, 2014; Keshk & Haijia, 2011; Kucharzewski, Slezak, & Franek, 2003; Klemm, Schumann, Udhardt, & Marsch, 2001; Fontana et al., 1990). DBC has been prepared in denser and less ductile forms with a particle size of 1–5 m (Keshk & Haijia, 2011). DBC exhibited a lower density value compared to that of commercial cellulose (Avicel PH 101 & 102). Both DBC and Avicel PH 101 exhibited sim- ilar behaviour during flow and binding processes. In addition, the weight loss of DBC occurred during a one-step degradation pro- cess from approximately 320 ◦ C to 380 ◦ C (Keshk & Haijia, 2011). To improve the functionality of BC without employing any extra- neous cross-linking agents, the reactivity of BC must be increased by molecular modifications (Hutchens, Benson, Evans, Rawn, & O’Neill, 2009; Fang, Wan, Tang, Gao, & Dai, 2009; Keshk, 2008; ∗ Corresponding author at: King Khalid University, Faculty of Science, Chemistry Department, P.O. Box 9004, Abha 61413, Saudi Arabia. Tel.: +966 559754436; fax: +966172417056. E-mail address: keshksherif@gmail.com (S.M.A.S. Keshk). Helenius et al., 2006; Keshk & Nada, 2003; Bielecki, Krystoynowicz, Turkiewicz, & Kalinowska, 2001). Periodate oxidation has been industrially utilized for di-aldehyde production of starch and cel- lulose (Veelaert, de Wit, Gotlied, & Verhe, 1997; Hutchens et al., 2009). Periodate oxidation is an extremely specific reaction to transform vicinal di-hydroxyl (glycol) groups to paired aldehyde groups without significant side products. In addition, this reaction is extensively used for the structural investigation of carbohy- drates (Uraz & Guner, 1997). In the periodate oxidation method, a large number of aldehyde groups are introduced into polysaccha- rides, which can be further converted to Schiff bases with primary amines (Kim, Kuga, Wada, Okano, & Kondo, 2000). Schiff bases make the di-aldehyde cellulose a valuable intermediate for cellulose- based functional materials, such as adsorbents for heavy metals and drug carriers as well as in the separation and analysis of pro- teins (Kim & Kuga, 2001). This study describes the synthesis of two novel Schiff’s bases via condensation reactions of periodate oxi- dized developed bacterial cellulose (ODBC) with sulfa drugs (i.e. sulfanilamide and sulfathiazole). The reactivity of ODBC towards sulfa drugs was also investigated via aldehyde content determina- tion. The physicochemical characterization of ODBC and its Schiff bases was performed using FT-IR, 1 H and 13 C NMR analyses, X-ray diffraction and DTA. http://dx.doi.org/10.1016/j.carbpol.2015.03.038 0144-8617/© 2015 Elsevier Ltd. All rights reserved.