Multiwalled carbon nanotube/polycaprolactone nanocomposites (MWNT/PCL) were prepared by in situ polymerization, whereby as-received MWNTs (PMWNTs) and purified MWNTs (A-MWNTs) were used as reinforcing materials. The A-MWNTs were purified by nitric acid treatment, which introduced the carboxyl groups (COOH) on the MWNT. The micrographs of the fractured surfaces of the nanocomposites showed that the A-MWNTs in A-MWNT/PCL were better dispersed than P-MWNTs in PCL matrix (P-MWNT/PCL). Percolation thresholds of the P-MWNT/PCL and A-MWNT/PCL, which were studied by rheological properties, were found at $2 wt % of the MWNT. The conductivity of the P-MWNT/PCL was between 10 À1 and 10 À2 S/cm by loading of 2 wt % of MWNT although that of the A-MWNT/PCL reached $10 À2 S/cm by loading of 7 wt % of MWNT. The conductivity of the P-MWNT/PCL was higher than that of the A-MWNT/PCL at the entire range of the studied MWNT loading, which might be due to the destruction of p-network of the MWNT by acid treatment, although the A-MWNT/PCL was better dispersed than the P-MWNT/PCL. The amount of the MWNT at which the conductivity of the nanocomposite started to increase was strongly correlated with the percolation threshold.

Polyacrylonitrile (PAN) nanofibers were prepared by an electrospinning technique, which were chemically modified with amidoxime groups. The silver nanoparticles were then synthesized on amidoxime modified PAN (OM-PAN), which was used for the photodegradation of methyl orange in aqueous solution. The SEM images showed that the average diameter of PAN nanofibers was below 200 nm. The SEM micrograph also showed that the silver nanoparticles were well dispersed on the surface of OM-PAN nanofiber mat. The micrograph also presented that the average size of silver nanoparticles was below 100 nm. The photodegradation study showed that the degradation of methyl orange in aqueous medium was increased as increased the irradaition time. The results illustrated that silver nanoparticles (Ag)/OM-PAN nanofiber mat degraded about 80 % of methyl orange within 6 h. The degradation efficiency was found to be pH dependent and maximum degradation was found at lower pH (about 90 % of dye is degraded at pH 2). The Ag/OM-PAN nanofiber dosage presented that the degradation of dye was increased as increased the catalyst dosage.

Polycaprolacton (PCL) and multiwalled carbon nanotubes/PCL (P-MWNT/PCL) were prepared by electrospinning technique. The average diameter of the nanofibers was below 400 nm. The mechanical properties of the P-MWNT/PCL nanofibers were higher than that of neat PCL nanofibers. It was also found that the mechanical properties of the composite nanofibers were decreased as increased the amount of P-MWNTs, which were due to the poor dispersion of the P-MWNTs in the PCL matrix or agglomeration of MWNTs at high concentration. The thermal stability of the P-MWNT/PCL nanofibers was higher than PCL nanofibers. The conductivity of the adsorbed P-MWNT on PCL (φ) nanofibers was 1.27 × 10 -4 S/cm.