Thermal electrical and dielectric properties of copolystyrenes bearing polar side groups and their composites

The greenish single-chain polymeric molecule-ball type CoPcs (SCPM-ball type CoPcs) were prepared via the macrocyclization reaction of cobalt phthalocyanine from poly(styrene-co-poly[4,4'-((((4-vinylbenzyl)azanediyl)bis(ethane-2,1diyl))bis(oxy))diphthalonitrile]) [P(PNDEAMSt-co-St)] (linear copolymer precursor) under diluted conditions at 140-150 oC in presence of cyclohexanol. The ball-type phthalocyanine moieties were incorporated into one side of the polymer chain. Both linear copolymer precursor and formation of ball-type cobalt phthalocyanine within a single-chain polymer were confirmed by FT-IR, 1H-NMR, UV/Vis spectroscopy and MALDI-TOF-MS techniques. Particularly, the formation of SCP-ball type CoPc complexes were characterized by almost disappearance of –C≡N band at 2230 cm-1 of the FT-IR and appearance of Q band between 600 and 673 nm. Two degradation models including Flynn-Wall-Ozawa (FWO) and Kissinger-Akahira-Sunose (KAS) methods were used to determine the apparent activation energies for approximately 70-80% of the thermal decomposition of linear copolymer precursor and SCPM-ball type CoPc at the range of room temperature and 500 oC at various heating rates. The SCPM-ball type CoPc/graphite oxide (GO) composites were prepared by Ultrasonic Homogeniser Sonicator. Dielectric constant of SCPM-ball type CoPc/GO composites show a slight increase with the increasing content of GO due to poor distribution and dispersion of graphite oxide in the SCPM-ball type CoPc. The composites treated with concentration-treated had a significant performance in dielectric constant but with a relatively higher dielectric loss compared with those of SCPM-ball type CoPc. The dc conductivity increased exponentially over the studied range of temperatures. The dc electrical conductivity of linear copolymer precursor/GO and SCPM-ball type CoPc/GO composites increased with increasing amount of GO. The polymer complexes conductiving exhibited Correlated Barrier Hoping (CBH) mechanism.