Disponible en ligne sur www.sciencedirect.com IRBM 34 (2013) 206–213 Original article Antimicrobial and antioxidant properties of novel synthesized nanocomposites based on polystyrene packaging material waste A.A. Haroun a,∗ , E.F. Ahmed b , N.R. El-Halawany c , H.A.A. Taie d a Chemical Industries Research Division, National Research Center, Dokki, Egypt b Chemistry of Microbial and Natural products Department, National Research Center, Dokki, Egypt c Polymers and Pigments Department, National Research Center, Dokki, Egypt d Plant Biochemistry Department, National Research Center, Dokki, Egypt Received 8 March 2012; received in revised form 23 November 2012; accepted 17 December 2012 Available online 1st February 2013 Abstract This work aims at preparation and characterization of novel synthesized nanocomposites based on polystyrene (Psty) packaging material waste. Moreover, the antimicrobial and antioxidant properties were examined and evaluated. The Psty was grafted with two different monomers such as acrylic and maleic acids (AAc and MAc, respectively) in presence of montmorillonite (MMT) using potassium persulfate as initiator under nitrogen atmosphere. The prepared nanocomposites were characterized using Fourier transform infrared spectroscopy (FT-IR), transmission (TEM) and scanning electron microscopes (SEM). Moreover, the antimicrobial activity was evaluated using agar disc diffusion method against gram negative bacteria such as: Klebsiella pneumonia, and Escherichia coli and gram positive bacterium (Sarcina lutea); in addition to the yeast fungus (Candida albicans). Furthermore, the radical scavenging ability of the prepared nanocomposites has been examined using the DPPH assay. © 2013 Elsevier Masson SAS. All rights reserved. 1. Introduction The antimicrobial agent-bound polymeric materials exhibit antimicrobial activities by slowly releasing active agents through hydrolysis, while some polymers are also antimicrobial active by themselves [1]. Polystyrene (Psty) is one of the widely used thermoplastic than any other polymer, for the reason that of its excellent physical properties, low cost and ease of fabrica- tion [2]. Nevertheless, its hardness, limited water absorption and chemical composition make it inert and resistant to microbial attack and it remain in the nature without any deformation for very long time and cause environmental pollution [3]. Modi- fication/functionalization of Psty is one of the alternatives to overcome such problem of disposal and make it technologically important. Addition of functionalities in the plastic waste makes it labile to microbial attack. Functionalization of Psty can be carried out through chemical method [4], photo-irradiation and graft copolymerization with vinyl monomers [5]. Antibacterial efficiency, sterilizing effect, adsorption of toxins and membrane ∗ Corresponding author. E-mail address: haroun68 2000@yahoo.com (A.A. Haroun). coating are pointed as some practical potential biomedical appli- cations of nanoclay [6]. The first research on the medicinal appli- cation of clay was recorded by Romans in 60 BC. Clay was used as Poultice in wound plaster, however, the mechanism of chem- ical interaction between clay and bacteria is not clearly known. Hu et al. investigated the antibacterial effect of ion exchanged montmorillonite (MMT) with Cu ions. Pharmacology studies have revealed that MMT adsorbed bacteria such as Escherichia coli, Staphylococcus aureus and immobilized cell toxins [7–10]. Haroun et al. [11,12] found that MMT showed no antibacterial effect, but could adsorb and kill bacteria when it was intercalated with antimicrobial activity materials. Antimicrobial polymers have been used as coating in many areas such as food processing, biomedical devices filters and additives for antifouling paints [13]. The medical device related infections are frequently asso- ciated with morbidity and more importantly, mortality and there- fore represent serious clinical problems [14]. Gorman et al. [15] described about 1000 fold increase in the resistance of clinical isolates of S. aureus and Pseudomonas aeruginosa to the non- antibiotic antimicrobial agent, hexetidine, in the biofilm state in comparison to the planktonic form. An excessive production of free radicals is thought to be responsible for high levels of oxida- tive damage, whereby species that contain unpaired electrons 1959-0318/$ – see front matter © 2013 Elsevier Masson SAS. All rights reserved. http://dx.doi.org/10.1016/j.irbm.2012.12.009