title: Synthesis and characterization of a new type of levan-graft-polystyrene copolymer.
abstract: Novel macromolecular graft copolymers were synthesized by reaction of the hydroxyl groups of the microbial polysaccharide levan, produced using Bacillus licheniformis, with polystyrene (Lev-g-PS). Synthesis was performed by the free radical reaction using potassium persulfate (PPS) as initiator. The prepared copolymer was characterized by FTIR, SEM, TG/DTA, XRD and (13)C NMR. The influence of the different conditions (reaction temperature, air or nitrogen atmosphere, reaction time, type of amines and ascorbic acid (AA) concentration) on the grafting reaction was investigated. Results showed that maximum percentage of grafting (58.1%) was achieved at a reaction temperature 70°C, in a nitrogen atmosphere and using dimethylethanolamine (DMEA) as the amine activator. On the basis of the obtained results, the likely reaction mechanism was proposed. Synthesized copolymers have better thermal stability in comparison with their initial components. Copolymers such as Lev-g-PS could potentially have many applications, such as compatibilizers and material for membranes.
authors: Faculty of Chemistry, University of Belgrade, Studentski Trg 12-16, Belgrade 11000, Serbia. Electronic address: brankakekez@chem.bg.ac.rs.
authors: Branka
authors: B
authors: Kekez
authors: Institute of Chemistry, Technology and Metallurgy, University of Belgrade, Njegoševa 12, 11000 Belgrade, Serbia. Electronic address: ggojgic@chem.bg.ac.rs.
authors: Gordana
authors: G
authors: Gojgić-Cvijović
authors: Institute of Chemistry, Technology and Metallurgy, University of Belgrade, Njegoševa 12, 11000 Belgrade, Serbia. Electronic address: djakovlj@chem.bg.ac.rs.
authors: Dragica
authors: D
authors: Jakovljević
authors: Faculty of Agriculture, University of Belgrade, Nemanjina 6, Belgrade 11080, Serbia. Electronic address: vlaver@agrif.bg.ac.rs.
authors: Vladimir
authors: V
authors: Pavlović
authors: Faculty of Chemistry, University of Belgrade, Studentski Trg 12-16, Belgrade 11000, Serbia. Electronic address: vbeskoski@chem.bg.ac.rs.
authors: Vladimir
authors: V
authors: Beškoski
authors: Faculty of Chemistry, University of Belgrade, Studentski Trg 12-16, Belgrade 11000, Serbia. Electronic address: apopovic@chem.bg.ac.rs.
authors: Aleksandar
authors: A
authors: Popović
authors: Faculty of Chemistry, University of Belgrade, Studentski Trg 12-16, Belgrade 11000, Serbia. Electronic address: mmvrvic@chem.bg.ac.rs.
authors: Miroslav M
authors: MM
authors: Vrvić
authors: Innovation Center, Faculty of Chemistry, University of Belgrade, Studentski Trg 12-16, Belgrade 11000, Serbia. Electronic address: nikolicv@chem.bg.ac.rs.
authors: Vladimir
authors: V
authors: Nikolić
keywords: Dimethylethanolamine (PubChem CID: 7902); Graft copolymer; Levan; Levan (PubChem CID: 5254051); Microbial polysaccharide; Potassium persulfate (PubChem CID: 24412); Styrene; Styrene (PubChem CID: 7501)