Revised Manuscript with Corrections: Polyurethane-Based Conductive Composites: From Synthesis to Applications

Single-side polypyrrole coated conductive and flexible polyurethane films

In this study, single-side polypyrrole (PPy) coated conductive stretchable polyurethane (PU) / PPy composite films were synthesized by chemical oxidative method in the acetonitrile (ACN)/H2O interface as a new alternative to two-side coated PU films which have already reported in the literature. One surface of the PU film was contacted with aqueous Py solution and the other surface with cerium ammonium nitrate (CAN) solution in ACN, so that only one surface of the film was coated with PPy and the resulting composite was named PU/PPy (PUP). This composite was characterized by four-point probe conductivity measurement, Fourier-transform infrared spectroscopy (FTIR), differential scanning calorimetry (DSC), scanning electron microscopy (SEM) measurements, and mechanical testing. The thickness of PPy coating was determined as 16 μm, by using polarized microscope imagines of crosssection of film. Tg value of the composite was obtained as -60.38 °C and the highest conductivity of PPy coated side of PU was obtained as 3.5 × 10-4 S cm-1, while the back side of PU film was still insulator.

Fabrication of Conductive, High Strength and Electromagnetic Interference (EMI) Shielded Green Composites Based on Waste Materials

Conventional conductive homopolymers such as polypyrrole and poly-3,4-ethylenedioxythiophene (PEDOT) have poor mechanical properties, for the solution to this problem, we tried to construct hybrid composites with higher electrical properties coupled with high mechanical strength. For this purpose, Kevlar fibrous waste, conductive carbon particles, and epoxy were used to make the conductive composites. Kevlar waste was used to accomplish the need for economics and to enhance the mechanical properties. At first, Kevlar fibrous waste was converted into a nonwoven web and subjected to different pretreatments (chemical, plasma) to enhance the bonding between fiber-matrix interfaces. Similarly, conductive carbon particles were converted into nanofillers by the action of ball milling to make them homogeneous in size and structure. The size and morphological structures of ball-milled particles were analyzed by Malvern zetasizer and scanning electron microscopy. In the second phase of the study, the conductive paste was made by adding the different concentrations of ball-milled carbon particles into green epoxy. Subsequently, composite samples were fabricated via a combination of prepared conductive pastes and a pretreated Kevlar fibers web. The influence of different concentrations of carbon particles into green epoxy resin for electrical conductivity was studied. Additionally, the electrical conductivity and electromagnetic shielding ability of conductive composites were analyzed. The waveguide method at high frequency (i.e., at 2.45 GHz) was used to investigate the EMI shielding. Furthermore, the joule heating response was studied by measuring the change in temperature at the surface of the conductive composite samples, while applying a different range of voltages. The maximum temperature of 55 °C was observed when the applied voltage was 10 V. Moreover, to estimate the durability and activity in service the ageing performance (mechanical strength and moisture regain) of developed composite samples were also analyzed.