Synthesis, characterization and electrial properties of poly N-Phenyl 2-Naphthyl amine and poly N-Ethyl aniline

Poly n-phenyl-2-naphthyl amine [PNPNA] and poly N-ethyl aniline [PNEA] have been prepared using potassium persulphate as an oxidizing agent. The polymers were characterized by various methods using spectrophotometric measurements, e.g., I.R. and UV-visible. Thermal gravimetric analysis [TGA] for PNEA indicated its great thermal stability up to 430 degree. A.C. resistivity and capacitance measurements have been used to characterize the electrical properties of the prepared polymers in the temperature ranges from 25 degree to 160 degree for and from 25 degree to 240 degree for PNEA. Log p, capacitance, Ea and dielectric constant values were obtained at different frequency ranges from 5OHz up to 100 kHz. The results suggest hopping conduction mechanism for the PNPNA pellets, the increase in conductivity being governed by the interchain hopping of polarons acting as charge carriers. The PNEA pellets, on the other hand, showed higher resistivity values at all frequency ranges than those of PNPNA. Also the A.C. resistivity tends to become temperature independent. Accordingly, the conductivity increased with increasing frequency. This behaviour is attributed to the presence of ethyl groups in the polymer chain that introduce new trap levels within the localized states

comparative histological study of healing following co2 laser and conventional surgical excision of oral leukoplakia

Twenty male patients ranged in age from 35-50 years and suffering from leukoplakia in the buccal mucosa; were selected to participate in this study. They were divided into two equal groups. In one group, the oral lesions were removed by co2 laser; and lesions of the other group were removed by ordinary surgical excision using scalpel. Biopsy specimens were taken from the removed lesions after 24 and 28 days. Tissue sections were prepared stained and examined to study the difference between healing in both types of wounds. The histological findings revealed that, the laser wound differed from the conventional wound. There was minimal damage to the adjacent tissue and a co-agulum of denatured protein was formed on the surface. The inflammatory reaction was less, fewer myofibroblasts were present and there was little wound contraction; less collagen was formed and epithelial regeneration was delayed and more irregular. Moreover, the lack of wound contraction and scarring after the use of laser; make it a preferable surgical tool for the removal of dysplastic epithelium affecting the oral cavity. This is particularly important where scarring might lead to interference with function; such as lesions situated near the comissure of the lips

Synthesis and characterization of iron complexes of tetraoxalyl para-phenylene diamine

A large number of inorganic compounds are known to contain metal ions of the same element in two different formal oxidation states, but few organometallic compounds of this type have been reported. Cowan et al. reported biferrocene Fe [II] Fe [III] picrate and Vertes and Suba examined the mixed iron states in formamide. The reaction between para phenylene diamine and aliphatic dibasic acids depends upon the molar ratio of the reactants and the experimental conditions employed. At a 1 : 4 molar ratio [para phenylene diamine: oxalic acid] under reflux condition, the tetrafunctional compounds is obtained. More recently tetrabasic [tetrasuccinyl urea] and tetraoxalyl urea were prepared]. The present work is mainly concerned with the reaction of para phenylene diamine with oxalic acid. The aim is to produce tetrafunctional product [tetraoxalyl para phenylene diamine][To p-phD] and to investigate the formation of Iron [II] and [III] complexes by Mossbauer and Infra-red spectroscopy