Synthesis, characterization and investigation of antimicrobial properties of anhydride containing co(ter)polymers, macrocomplexes, macrobranched graft copolymers, organo-sodium-bentonite nanocomposites

In this study; water soluble, showing polyelectrolyte behavior and antimicrobial activity co(ter)polymers of N-vinylimidazole (NVIM), N-isopropyl acrylamide (NIPA), methyl methacrylate (MMA), 2-hydroxyethyl methacrylate (2-HEMA) and 2-hydroxypropyl methacrylate (2-HPMA), maleic and citraconic anhydride (MA and CA) monomers were were synthesized by free radical polymerization under nitrogen atmosphere in 1,4-dioxane medium using 2,2-azobisisobutironitrile (AIBN) as initiator at 65 oC. Branched poly(ethylene imine) (PEI) was bonded to the synthesized co(ter)polymers in deionized water in order to obtain a polycationic macrocomplex structure. Methoxy ended poly(ethylene glycol) (PEG) and poly(ethylene oxide) (PEO) was bonded to the copolymers by esterification reaction in 1,4-dioxane in order to compose macrobranched graft copolymers. An organo-sodium-bentonite (organo-Na-bentonite) was prepared from pure sodium-bentonite (Na-bentonite) by cetiltrimethylammonium bromide (CTMAB) quaternary ammonium salt. Co(ter)polymer/organo-Na-bentonite nanocomposites were prepared with 50%, 60%, 66,7% and 80% organo-Na-bentonite content. Solutions of co(ter)polymer, macrocomplexes, macrobranched graft copolymers and nanocomposites were prepared in different solvents and solubilities were determined. Structures of co(ter)polymer, macrocomplexes, macrobranched graft copolymers and nanocomposites were characterized by UV-visible, FTIR, 1H NMR and 13 C NMR spectra; their thermal properties were determined by TGA, DTA, DSC and DMA; surface morphology were investigated by SEM and TEM; their intrinsic viscosity measurement were performed; their crystal structure and crystal percentages were determined by XRD. Number of carboxylic asid groups of co(ter)polymer were determined by titration method. Monomer mol percents were determined from elementel analysis, FTIR, 1H NMR spectra and number of carboxylic asid groups of co(ter)polymers. Monomer reactivity ratios of copolymers were calculated by using Kelen-Tudos (K-T) and Fineman-Ross (F-R) methods. This results were compatible with each other. UV-visible, FTIR, 1H NMR and 13C NMR spectra; the result of elementel analysis, SEM and XRD; termal analyses were showed that it was polymer and formation of alternating co(ter)polymers. Comparative analysis of thermal behavior (Ti, Tm, Tf, Td, Tg, Tm) of co(ter)polymer and nanocomposites prepared in the absence and presence of organo-Na-bentonite proved the significant increase of thermal, crystalline and mechanical properties of nanocomposites due to formation of nano-structure. Absence of peaks in XRD results of nanocomposites indicated the exfoliated structure. TEM images also confirmed this result. Antimicrobial activities of all materials are synthesized were performed by well diffusion method and determination of minimum inhibition concentration (MIC) against pathogen gram-positive bacteria (Staphylococcus aureus, Bacillus subtilis and Streptococcucs faecalis), pathogen gram-negative bacteria (Eschericia coli, Klebsiella pneumoniae, Pseudomonas aeruginosa, Shigella sonnei, Salmonella typhi and Salmonella paratyphi) and fungus (Candida albicans and Saccharomyces cerevisiae). Antimicrobial activities of synthesized materials were compared with various antibiotic (Eritromicin, Gentamicin, Penicillin G and Ampicillin) and antifungal (Ketoconazole) drugs. The highest values of antimicrobial activity were measured against pathogen gram-positive bacteria. Compared with drugs used in the antimicrobial activity of the synthesized substances at least one of them as they sometimes have more activity was observed.