Syntheses and Electrical Conductivities of Aliphatic Polyrhodanines

Abstract

Aliphatic polyrhodanines were prepared by the polycondensation reaction of bisrhodanines with dialdehydes terephthalaldehyde(TPA), glutaraldehyde(GA), and glyoxal(GO)(Table 5). The bisrhodanines(ethylene bisrhodanine(EBR), trimethylene bisrhodanine(TBR), hexamethylene hisrhodanine(HBR), decamethylene bisrhodanine(DBR), and dodecamethylene bisrhodanine(DoBR)) were synthesized from the corresponding diamines via dithiocarbamate (Tables 1 and 2).
The infrared and ultraviolet absorption spectra of the polymers were measured to confirm their proposal structures. Elementary analysis agreed with the values calculated for the aliphatic polyrhodanine (Table 6). The reduced viscosities of the obtained polymers were 0.05∼0.35 in concentrated sulfuric acid (Tables 3 and 4).
In a series of aliphatic polyrhodanines prepared from bisrhodanine with TPA, the electrical resistivity and its activation energy(E_a) increased with increasing the number of methylene chain. The values of E_a(eV) were 0.9₄ for EBR-TPA, 1.3₅ for TBR-TPA, 1.8, for FIBR-TPA, 2.2₅ for DBR-TPA, and 2.3₆ for DoBR-TPA (Fig.2 and 3). For the aliphatic polyrhodanines, EBR-GO and EBR-GA, their electrical conductivity above their softening temperature were found to be higher than the values measured at low temperature occurred the drastic change of conductivity coincides with the temperature appeared the weight loss by thermogravimetric analysis about 135°C for EBR-GA, and about 148°C for EBR-GO.