EMI shielding effectiveness and dielectrical properties of SBS/PAni.DBSA blends: Effect of blend preparation

Abstract

This work investigates the effect of different preparation routes including mechanical mixing and in situ polymerization of aniline on the electromagnetic interference shielding effectiveness (EMI SE) over the X-band (8-12 GHz) frequency range for polyaniline doped with dodecylbenzene sulfonic acid (PAni.DBSA) filled in styrene-butadiene-styrene triblock copolymer matrix. The dc conductivity and dielectrical properties were also investigated. For all systems, the electrical conductivity, dielectric constant, and EMI SE increased with the increase in the concentration of PAni.DBSA. Blends prepared by the in situ polymerization exhibited higher conductivity and dielectric constant and better EMI SE characteristics than the physical blends with similar amount of PAni.DBSA. EMI SE value as high as À35 dB has been achieved with about 30% of PAni.DBSA prepared by the in situ polymerization. Regarding physical blends, those involving PAni.DBSA prepared by a redoping process displayed better EMI SE. For all systems under consideration, the conductivity and EMI SE bear an exponential relationship that can be represented by a master curve.

Electrically conductive composites of polyurethane derived from castor oil with polypyrrole‐coated peach palm fibers

“…The PPy amount in the PPF fibers surface was of 36.3 wt%. It is worthwhile to observe that the conductive layer on the PPF surface is responsible for the high electrical conductivity of (2.2 6 0.3) 3 10 21 S cm 21 , which is close to that of neat PPy (1.5 6 0.1 S cm 21 ) and about 9 orders of magnitude higher than those of neat PPF ((3.5 6 0.2) 3 10 210 S cm…”

“…The DMA measurements were carried out in a nitrogen gas environment, at a heating rate of 58C min 21 and at 1 Hz with a single cantilever.…”

“…The bands at 2974 and 2905 cm 21 are related to the stretching of the methyl and methylene groups, respectively [8]. The C@O stretching vibrations of the hemicellulose and lignin are represented by the bands at 1734 and 1647 cm 21 , respectively [7,24]. The bands at 1377, 1242, and 1038 cm 21 can be ascribed to the CAH asymmetric deformation, CAO stretching vibration of the acetyl group of hemicellulose and to plane deformation of the aromatic CAH, respectively.…”

“…Figure 2 shows the FTIR spectra of the PPF, PPy and PPF-PPy. The spectrum of PPF exhibits an absorption band at 3335 cm 21 assigned to stretching vibrations of the hydroxyl group [16]. The bands at 2974 and 2905 cm 21 are related to the stretching of the methyl and methylene groups, respectively [8].…”

“…The C@O stretching vibrations of the hemicellulose and lignin are represented by the bands at 1734 and 1647 cm 21 , respectively [7,24]. The bands at 1377, 1242, and 1038 cm 21 can be ascribed to the CAH asymmetric deformation, CAO stretching vibration of the acetyl group of hemicellulose and to plane deformation of the aromatic CAH, respectively. At 1157 cm 21 a band related to CAOAC groups can be observed [25].…”