EXPERIMENTS: New graphene-philic surfactants carrying aromatic moieties in the hydrophilic headgroups and hydrophobic tails were synthesized by swapping the traditional sodium counterion with anilinium. 1H NMR spectroscopy was used to characterize the surfactants. These custom-made surfactants were used to assist the dispersion of GNPs in natural rubber latex matrices for the preparation of conductive nanocomposites. The properties of nanocomposites with the new anilinium surfactants were compared with commercial sodium surfactant sodium dodecylsulfate (SDS), sodium dodecylbenzenesulfonate (SDBS), and the previously synthesized aromatic tri-chain sodium surfactant TC3Ph3 (sodium 1,5-dioxo-1,5-bis(3-phenylpropoxy)-3-((3phenylpropoxy)carbonyl) pentane-2-sulfonate). Structural properties of the nanocomposites were studied using Raman spectroscopy, field emission scanning electron microscopy (FESEM), and high-resolution transmission electron microscopy (HRTEM). Electrical conductivity measurements and Zeta potential measurements were used to assess the relationships between total number of aromatic groups in the surfactant molecular structure and nanocomposite properties. The self-assembly structure of surfactants in aqueous systems and GNP dispersions was assessed using small-angle neutron scattering (SANS).
FINDINGS: Among these different surfactants, the anilinium version of TC3Ph3 namely TC3Ph3-AN (anilinium 1,5-dioxo-1,5-bis(3-phenylpropoxy)-3-((3phenylpropoxy)carbonyl) pentane-2-sulfonate) was shown to be highly efficient for dispersing GNPs in the NRL matrices, increasing electrical conductivity eleven orders of magnitude higher than the neat rubber latex. Comparisons between the sodium and anilinium surfactants show significant differences in the final properties of the nanocomposites. In general, the strategy of increasing the number of surfactant-borne aromatic groups by incorporating anilinium ions in surfactant headgroups appears to be effective.
MATERIALS AND METHODS: The most recent publications regarding the impact of various external factors on Pub Med, Google, TOXLINE, Chem Abstract, were analyzed with the radiological data that were found in Milan hospitals database.
RESULTS: The relationship between food consumption and nasopharyngeal cancer are not clear and statistically insignificant in Indonesia. In Malaysia, the preparation of natural rubber for the use of formaldehyde is a dangerous environmental factor. The same exposure is a risk factor in Guangdong, where many workers are employed in the wood panel industry. Incidence of cancer in these Chinese ethnic groups decreases when they migrate to other countries. In the last 5 years, few cases were recorded in Italy, without any apparent change in ethnic environmental factors or HBV infection Discussion: In the production of natural rubber, a lot of people are exposed to formaldehyde during the various steps of preparation and production such as stripping, drying and coagulation without observing proper environmental hygiene precautions. The same working conditions are present in industrial production of wood panels in Guangdong, China. The relationship between exposure to formaldehyde and nasopharyngeal cancer is demonstrated by the fact that epidemiological studies on the population of this Chinese district whose immigrant populations were not exposed to these pollutants, the appearance of these tumors decreases. Also an examination of our radiological data in Italy shows that in about one hundred sixty cases of nasopharyngeal cancer none of the patients were Indonesian or Chinese Conclusion: The preliminary results of our study suggest that EPST-BARR virus could be a risk factor if associated with exposure to compounds such as formaldehyde which is present in industrial productions of countries like Indonesia, Malaysia, and China.