Poly(acrylonitrile-co-methylmethacrylate) P(AN-co-MMA) was synthesized by precipitation polymerization method. Using Carica papaya (C. papaya) plant leaves extract, silver nanoparticles (AgNPs) were prepared via green synthesis. The copolymer solution in N,N dimethyl formamide was mixed with variable weight percentages of the prepared AgNPs (i.e., 1.0, 3.0, 5.0, 7.0 and 9.0 wt%). The produced copolymer composites were characterized by X-ray diffraction, scanning electron microscope (SEM), energy dispersive X-ray analysis, infrared spectra, dynamic mechanical analysis (DMA) and thermogravemetric analysis (TGA). Bacterial inhibition of the prepared copolymer nanocomposites was also evaluated for two types of bacteria (i.e., Staphylococcus aureus ATCC 12600 as Gram-positive bacteria and Escherichia coli ATCC 11775 as Gram-negative bacteria). SEM showed the fine dispersion of AgNPs in the copolymer matrix at 5 wt%. DMA indicated an increase in the storage modulus and a reduction in tan ${\delta}$ (damping) by increasing AgNPs loading up to 9 wt%. TGA illustrated that AgNPs improved the P(AN-co-MMA) thermal stability. AgNPs improved the bacterial inhibition of P(AN-co-MMA) against the two tested bacteria. Moreover, the prepared copolymer composites could be used for biomedical, pharmaceutical and industrial applications.

Carboxylated functionalized multiwall carbon nanotubes (FMWCNTs) were prepared via nitric acid treatment. Decoration of FMWCNTs side walls with silver nanoparticles (AgNPs) was performed by mixing in silver nitrate (AgNO$_3$) solution giving FMWCNTs-Ag. Poly(vinyl chloride) (PVC) nanocomposites based on both pristine MWCNTs and its decorated form FMWCNTs-Ag in various contents (i.e., 0.5, 1.0, 3.0 and 5.0 wt%) were prepared in tetrahydrofuran solution followed by film casting. The obtained nanocomposites were specified by X-ray diffraction (XRD), transmission electron microscope (TEM), Raman spectroscopy, dynamic mechanical analysis (DMA), thermal analysis and dielectric properties measurements. The bacterial inhibition of the prepared film samples was also tested against Gram-positive (i.e., Bacillus subtilis and Staphylococcus aureus) and Gram-negative bacteria (i.e., Escherichia coli and Pseudomonas aeruginosa). The data were explained in according with filler type and loading. XRD analysis confirmed the homogeneous dispersion of FCNTs-Ag in PVC matrix. TEM showed that large number of AgNPs were anchored to FCNTs surface. This was confirmed by Raman spectra. DMA illustrated that with increasing FCNTs-Ag content up to 5.0 wt%, higher storage and loss moduli as well as smaller tan ${\delta}$ values with shifting to higher $T_g$ were obtained in comparison to composites with pristine CNTs. Thermogravimetric analysis indicated that increasing CNTs and FCNTs-Ag contents in PVC matrix up to 5.0 wt% improved PVC thermal stability. Differential thermogravimetric analysis showed a delay in PVC degradation rate on the initial step for composites based on FCNTs-Ag. Dielectric properties measurements illustrated that PVC composites with FCNTs-Ag exhibited higher electrical conductivity as compared with those based on pristine CNTs, but with the same order of magnitude (10$^{-8}$ ${\Omega}^{-1}$ cm$^{-1}$). This indicates that the prepared composite films can be applicable as electrostatic dissipated materials as the range of such application is 10$^{-9}$ to 10$^{-5}$ ${\Omega}^{-1}$ cm$^{-1}$. They also showed bacterial inhibition against the tested bacteria. This promises a potential use of the nanocomposites in medical fields as antimicrobial agents for the treatment of bacterial infection.