Search

The purpose of the current work was to produce conducting electroactive membranes from bacterial cellulose (BC) coated with polypyrrole (PPy) via in situ chemical polymerization of pyrrole at 4 °C using FeCl 3 as oxidant agent. The electrical conductivity, tensile, thermal and electrochemical properties of BC-PPy membranes were investigated. The results revealed that the uniformly coating of PPy nanoparticles on the surface of BC template achieved high electrical conductivity of 3.39 S cm −1 and a specific capacitance of 191.94 F g −1 at 5 mv s −1 scan rate. The high conductivity and specific capacitance of the present BC-PPy membranes opens new potential applications for BC in various fields as biosensors, flexible electronics, or energy storage devices. [ABSTRACT FROM AUTHOR]

In this work, we prepare cellulose nanopapers of high mechanical performance and with the electrical conductivity of a semiconductor. Cellulose nanofibers (CNF) from bleached softwood pulp were coated with polypyrrole (PPy) via in situ chemical polymerization, in presence of iron chloride (III) as oxidant agent. The structure and morphology of nanopapers were studied, as well as their thermal, mechanical and conductive properties. Nanopaper from pure CNF exhibited a very high tensile response (224 MPa tensile strength and 14.5 GPa elastic modulus). The addition of up to maximum 20% of polypyrrole gave CNF/PPy nanopapers of high flexibility and still good mechanical properties (94 MPa strength and 8.8 GPa modulus). The electrical conductivity of the resulting CNF/PPy nanopaper was of 5.2 10 −2 S cm −1 , with a specific capacitance of 7.4 F g −1 . The final materials are strong and conductive nanopapers that can find application as biodegradable flexible thin-film transistor (TFT) or as flexible biosensor. [ABSTRACT FROM AUTHOR]

In this work, the feasibility of converting dead leaf biomass into green activated carbon for use as a reinforcement filler in natural rubber composites was assessed. The dead leaf activated carbon (DLAC) was prepared by pyrolysis at 550, 700, 900, and 1000 °C at a heating rate of 10 °C min−1 under nitrogen gas flow of 100 cm3 min−1 and was activated by CO 2 gas at the same flow rate when the pyrolysis temperature was reached. The properties of DLACs were characterized by particle size analysis, density, scanning electron microscopy, elemental energy-dispersive X-ray spectroscopy and Raman spectroscopy. The results revealed that the DLAC obtained by pyrolysis at 1000 °C had a small particle size of 28.86 μm; a highly porous structure; high carbon purity, at 82.58%; and a low density, at 1.588 g cm−3. The effect of different DLAC contents (5, 10, and 15 phr) on the curing properties and the physical and mechanical performance of the rubber composites was investigated and compared with rubber composites containing carbon black (CB). The results showed that the addition of DLAC increased the maximum torque and reduced the scorch and cure times. The tensile strength for rubber composites containing 15 phr of DLAC increased by 8%, the M100 and M300 improved 40%, and the elongation at break and crosslink density decreased by approximately 5% and 24%, respectively. The studied DLAC is a promising, cost-effective alternative to commercial carbon black for improving the performance of rubber composites. Image 1 • From dead leaf biomass to Dead leaf activated carbon (DLAC) by pyrolysis. • Potential use of DLAC as reinforcement filler in natural rubber. • DLAC filled rubber give similar mechanical properties to carbon black filled rubber. • DLAC is a promising cost effective to commercial carbon black in rubber composites. [ABSTRACT FROM AUTHOR]

The objective of this study was to compare the physical and mechanical performance of poly(lactic acid) (PLA), acrylonitrile butadiene styrene (ABS), and nylon 6 fabricated using fused deposition modeling (FDM) and conventional injection molding. It is found that different processing methods did not affect the viscosity of the samples, and the percentage difference for the density measurement is less than 4%. Water absorption of FDM samples is approximately 108% higher compared to those fabricated using the injection molding. The results also revealed that the FDM method did not strongly affect the degree of crystallinity of ABS, but it increased the degree of crystallinity of PLA and nylon 6. The tensile strength, Young's modulus, elongation at break, and impact strength of FDM samples were approximately 48%, 50%, 48%, and 78%, lower compared with the injection molded samples. The results presented can provide a guide to manufacturing the final products using FDM with the desired performance. Image 1 [ABSTRACT FROM AUTHOR]

In the current work, flexible, lightweight, and strong conductive nanopapers based on cellulose nanofibers (CNFs) with poly(3,4-ethylenedioxythiophene):polystyrene sulfonate (PEDOT:PSS) and/or polypyrrole (PPy) were prepared by following a mixing and in situ chemical polymerization method. A successful homogeneous coating of PEDOT:PSS on cellulose nanofibers occurred by means hydrogen-bonding interactions between the hydroxyl functionalized CNF and the electronically charged PEDOT:PSS, as shown by FTIR spectra. The electrical conductivity and the specific capacitance of CNF-PEDOT:PSS nanopapers were 2.58 S cm −1 and 6.21 F g −1 , respectively. Further coating of PPy produced a substantial improvement on the electrical conductivity (10.55 S cm −1 ) and the specific capacitance (315.5 F g −1 ) of the resulting CNF-PEDOT:PSS-PPy nanopaper. A synergistic phenomenon between both conductive polymers supported the high electrical conductivity and specific capacitance of the ternary formulation. Moreover, CNF-PEDOT:PSS-PPy nanopaper showed higher mechanical properties and it was more flexible than the nanopaper containing only polypyrrole conducting polymer (CNF-PPy). It is concluded that the good mechanical, electrical and electrochemical properties of the ternary formulation can apply for smart nanopaper in flexible electronics and energy storage devices. [ABSTRACT FROM AUTHOR]