Radiation Grafting of Polyethylene onto Conductive Carbon Black and Application as a Novel Gas Sensor

Abstract

ABSTRACT:Radiation grafting of polyethylene (PE) onto carbon black was carried out by γ-ray irradiation of PEadsorbed carbon black. The percentage of PE grafting and decomposition temperature of PE grafted onto the surface were determined by thermogravimetric analysis. At low irradiation temperature, the percentage of grafting was very small in spite of higher irradiation dose. On the contrary, at high temperatures near or above the melting point of PE, the grafting of PE onto the carbon black surface proceeded and the percentage of grafting exceeded 90% when the irradiation dose reached to 200 kGy. The results indicate that the adsorbed PE was completely grafted onto the carbon black surface. The decomposition temperature of the grafted PE on the surface was higher than both free (unadsorbed) PE and adsorbed PE on the carbon black surface, indicating that there is a covalent bond between the carbon black and PE molecule. Using the PE-grafted carbon black and PE, conductive PE/PE-grafted carbon black composite was prepared. Electric resistance suddenly increased in cyclohexane vapor over 10 4 times, and returned to initial resistance when transferred to air, indicating that the composite can be used as a novel gas sensor.

Single-step process to improve the mechanical properties of carbon nanotube yarn

“…At this point, it should be noted that, to date, there are some previous reports on the use of radiation grafting polymerization to functionalize graphitic nanostructures [30,33–34]. This kind of grafting remains the subject of investigation because of a variety of structural transformations that may occur in carbon nanostructures under irradiation and different experimental configurations producing interesting and unexpected results.…”

Novel gas and contamination sensor materials from polyamide-block-poly(ethylene oxide)-grafted carbon black

“…The ␥-ray radiation grafting of PA-b-PEO onto a carbon black was carried out by two-step process [17]. PA-b-PEO was adsorbed onto carbon black surface as follows.…”

“…Recently, we achieved the grafting of polyethylene onto carbon black surface by trapping of polyethylene radicals formed by ␥-ray irradiation [17], and pointed out that the grafting method was very effective in the case of the grafting onto carbon blacks having a few or no functional groups. Therefore, the grafting of PA-b-PEO onto conductive carbon black was investigated by ␥-ray irradiation of PA-b-PEOadsorbed carbon black.…”

Modeling and experimental testing of the effect of solvent absorption on the electric properties of styrene butadiene rubber/carbon black chemical sensors

“…For example, with this type of materials sensors that measure pressure [1,2], strain [3] and temperature [4][5][6][7][8] has been designed. Also a number of chemical sensors to detect; liquid leaks [9][10][11][12][13][14][15][16][17][18][19][20][21][22][23][24], vapors [25][26][27][28][29], gases [30][31][32][33][34], and even artificial noses [35][36][37][38][39][40] have been recently introduced. When the carbon/polymer composites come into contact with a substance that is chemically compatible with the polymeric matrix, its conductivity gradually decreases with the exposure to this substance.…”