Journal of Polymer and Biopolymer Physics Chemistry, 2014, Vol. 2, No. 1, 12-24 Available online at http://pubs.sciepub.com/jpbpc/2/1/3 © Science and Education Publishing DOI:10.12691/jpbpc-2-1-3 Physicochemical, Spectroscopic and Rheological Studies on Eucalyptus Citriodora (EC) Gum Nnabuk Okon Eddy 1,2,* , Inemesit Udofia 1 , Adamu Uzairu 1 , Anduang O. Odiongenyi 2 , Clement Obadimu 2 1 Department of Chemistry, Ahmadu Bello University, Zaria, Kaduna State, Nigeria 2 Department of Chemistry, Akwa Ibom State University, Ikot Akpaeden, Akwa Ibom State *Corresponding author: nabukeddy@yahoo.com Received November 13, 2013; Revised January 14, 2014; Accepted February 14, 2014 Abstract Analysis of physicochemical properties of Eucalyptus citriodora gum revealed that the gum is mildly acidic, brownish in colour, ionic and has the potentials to swell four times its original volume. GCMS analysis of the gum indicated the presence of some carboxylic acids, pyran-4-one, 1,3-dioxolane, benzofuran and 1,2-ethanediyl acetate while analysis of its FTIR spectrum revealed functional groups that are common to polysaccharides. Scanning electron micrograph of the gum also revealed the existence of particle aggregations with some internal bridges within the system. Rheological properties of the gum were found to be affected by pH, concentration, temperature and by the presence of some electrolytes (KCl, CaCl 2 , AlCl 3 and urea). Average value of intrinsic viscosity deduced from Huggins and Kraemer plots was 3.51 dL/g while the sum of their constants was 0.36 (i,e< 0.5 and suggested the absence of molecular association). Calculated value of the Power law constant was (b= 0.812) less than unity and pointed to a rod like conformation. From the Master’s curve, the existence of dilute and concentrated regimes, (corresponding to η sp0 α C 1.04 (at C> C*) and η sp0 α C 0.95 (at C < C*) respectively) was established. Eucalyptus citriodora gum is a shear thinning, non-Newtonian polymer that is characterized by pseudoplastic behavior. The gum has some potentials for use as food additives and for other industrial applications. Keywords: Eucalyptus citriodora gum, physicochemical parameters, GCMS, FTIR, SEM, rheology Cite This Article: Nnabuk Okon Eddy, Inemesit Udofia, Adamu Uzairu, Anduang O. Odiongenyi, and Clement Obadimu, “Physicochemical, Spectroscopic and Rheological Studies on Eucalyptus Citriodora (EC) Gum.” Journal of Polymer and Biopolymer Physics Chemistry, vol. 2, no. 1 (2014): 12-24. doi: 10.12691/jpbpc- 2-1-3. 1. Introduction Exudate gums are obtained as natural exudates of different tree species and exhibit unique properties in a wide variety of applications including pharmaceutical, food, adhesive, paper, textile and other industries [1]. For example, Albizia zygia and some Albizia lebbeck gums are useful as natural emulsifiers for some foods, pharmaceutical and as a substitute for Arabic gum in the mining and metallurgical industries [2,3]. In the froth flotation of base and platinum group metal ores, guar gum is used as a depressant for naturally hydrophobic waste minerals such as talc. The role of polysaccharide is to render the metal hydrophilic and prevents its flotation, after it is been adsorbed on the gum surface. In the pharmaceutical industries, functional properties of Guar gum are of primary importance for controlling the release of drugs in the gastrointestinal tract, such as carrier for colon targeted drugs, for anti-cancer drugs in the treatment of colorectal cancer and for oral rehydration solutions in the treatment of cholera in adults [4]. Guar gum is also used in transdermal drug delivery systems, as a synthetic cervicle mucus and as a visco-supplementation agent in osteoarthritis treatment. Detarium senegalense and Gmelin gums have been reported to be useful in pharmaceutical and food industries. They have the potential of controlling drug release and in modifying the texture of some food [5]. The various applications that can be derived from gums have been found to depend on their functional properties such as physicochemical, proximate, cationic content, phytochemical and rheological properties. For example, in spite of its favourable rheological composition, Albizia lebbeck gum cannot be used as food additives because of its high content of tannins and high proportion of aluminum [2]. Pablyana et al. [4], stated that the presence of protein in polysaccharides can induce an inflammatory response in tissues, which can inhibit the pharmacological uses of gums. Yadav et al. [6] found that emulsifying properties of polysaccharides depends on its turbidity, Interfacial rheology of gums has also been found to be an essential parameter in predicting the emulsifying properties of gums [7]. Fenugreek gum is widely used as thickening, water holding, stabilizing and emulsifying agents in food industries because its galactose and manose content gives it a high viscosity in aqueous solution [8]. Similarly, Rinaudo [9] stated that gum exudates have wider industrial applications because of their excellent water holding capacity (which facilitate the production of gels or highly viscous solutions). Gums also have the