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Blends of poly(lactic acid)/polycaprolactone (PLA/PCL) were electrospun under various conditions to study the influence of solution concentration, feed rate and voltage supply on the morphology of the nanofibers. To improve compatibility and to help produce fine electrospun nanofibers, an L-lactide/caprolactone (LACL) copolymer was introduced as a compatibilizer in the PLA/PCL blends. It was found that the solution concentration was a principal governing factor. The mean diameter of the fibers increased with the solution concentration, feed rate and voltage. Too high of a concentration and feed rate caused the fibers to stick to each other. A slow feed rate, 10% solution concentration, and 20 kV voltage were capable of producing thin, smooth and uniform fibers. Preliminary biocompatibility assays of the nanofibers were conducted with NIH 3T3 cells. The cells grown on the nanofiber blend exhibited spindle-like morphologies. The addition of PCL and LACL copolymer was found to improve the biocompatibility of PLA nanofibers, suggesting their potential application as cell culture scaffolds. [ABSTRACT FROM AUTHOR]

In this study, a new method of fabricating conductive NR nanocomposites was proposed. Graphene oxide (GO) was obtained through oxidization and exfoliation of graphite and was employed as a reinforcing nanofiller for natural rubber (NR). GO/NR nanocomposites with different concentrations of GO were prepared by a latex mixing and casting method. The nanocomposites were characterized by Raman spectroscopy and TEM, and the thermal and mechanical properties were evaluated by TGA, DSC, tensile testing, and DMA. The results showed that the nanocomposite showed a segregated 'weblike' morphology. The addition of GO slightly decreased the glass transition temperature of NR and improved the thermal stability of the material. The tensile strength and storage modulus of the nanocomposites significantly increased with the GO contents, indicating GO had a strong reinforcing tendency on NR. The electrically conductive reduced graphene oxide (r-GO)/NR nanocomposites were obtained by immersing GO/NR nanocomposites in a hydroiodic (HI) acid aqueous solution for reduction. HI acid can efficiently reduce the GO into graphene in 2 h at 60°C. The volumetric electrical conductivity of the nanocomposites increased with the r-GO contents, and the conductivity of the 5% r-GO/NR nanocomposite was as high as 1 S/m, which showed its promising application as stretchable electrical conductors and elastomers. POLYM. COMPOS., 38:E199-E207, 2017. © 2016 Society of Plastics Engineers [ABSTRACT FROM AUTHOR]