Characteristics and properties of wood/polyaniline electromagnetic shielding composites synthesized via in situ polymerization

Abstract

Semiconducting wood/polyaniline (PANI) composites were synthesized via in situ polymerization of aniline monomer, which was impregnated into the wood veneer in advance. Thus, the resulting composites exhibited the characteristics of the conducting PANI and natural wood. The light microscopy and scanning electron microscopy images showed that PANI was uniformly dispersed into the wood substrate. The weight percent gain and volume bulk increase of the composites were 16.13% and 6.21%, respectively. The equilibrium water absorption studies showed that the composites were less hydrophilic, because of the addition of hydrophobic PANI. The electrical conductivity of the wood/PANI composite ranged from 2.57 × 10−5 to 9.23 × 10−3 S cm−1 and was tuned by changing the phosphoric acid concentration. The electromagnetic shielding effectiveness of the wood/PANI composites was mainly in the range 30–60 dB, which may be used for general industry or commercial electronics. Fourier transform infrared spectra revealed that PANI was closely polymerized onto the wood substrate and allowed the accessibility of the amine groups of the aniline to the hydroxyl groups of the wood. Furthermore, the X‐ray diffraction analysis indicated that the crystal lattice of the crystalline cellulose region was not damaged, and the relative crystallinity of wood increased. POLYM. COMPOS., 39:537–543, 2018. © 2016 Society of Plastics Engineers

Highly Conductive Cellulose Network/Polyaniline Composites Prepared by Wood Fractionation and In Situ Polymerization of Aniline

“…The appearance of characteristic bands of both CN and PANI with small shifts in the FTIR spectrum of the CNP composite (Figure a) confirmed the interaction between CN and PANI during the formation of the composite . The intensity of the peak at 3400 cm −1 for the CNP composites significantly reduced in comparison to that of the CN spectrum, possibly ascribed to the influence of PANI particles on the hydrogen bonds in cellulose . This suggests an increase in the electron density of PANI chains that results in the increase in conductivity of the CNP composite .…”

“…As previously reported, PANI is a noncrystalline substance, consistent with the findings in this study. The XRD pattern of the CN sample showed three peaks at 2θ = 17.2°, 23.2°, and 35.2°, which were attributed to the diffraction of the (010), (002), and (040) planes of cellulose, respectively . The diffraction peaks assigned to both PANI and CN appeared in the XRD pattern of the CNP composites, with the main difference between them being the reduced intensity of peaks attributed to cellulose, indicating the partial destruction of crystalline structure for cellulose.…”

“…a) WPG and VER of the CNP composites prepared with different HCl concentrations (Data provided as the mean ± standard deviation); b) comparisons of WPG and VER of the reported and present wood‐based PANI composites …”

“…The high conductivity and tunable properties of PANI provides an excellent additive that can be composited with wood to realize the conductivity of wood composites . The wood matrix allows the aniline monomer to polymerize inside the wood, enabling the interior conductivity of the wood/PANI composites . However, the main obstacle to the development of wood/PANI composites is their extremely low conductivity.…”

“…Also, as mentioned, there is an urgent need to improve the electrical conductivity of wood/PANI composites. In situ polymerization has been widely used to prepare wood/PANI composites, but it still cannot effectively improve the conductivity of the composites. Consequently, it is necessary to explore some novel methods to enhance the in situ polymerization of aniline in the inner structure of matrix materials and enhance the conductivity of the composites.…”