• Nuclear Engineering and Technology
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• v.13 no.4
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• pp.245-253
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• 1981

The properties of polyethylene materials exhibit good insulation and radiation resistance, but exhibit poor flame resistance. Flame retardant properties of the polyethylene were improved by the radiation induced grafting or crosslinking. When the various flame retardants were fixed onto polyethylene, the amount of fixation in grafting was increased with the increase of radiation dosages. In the case of grafting, it is necessary for high grafting yield that the polyethylene films were swelled before irradiation with ${\gamma}$-rays or electron beams. It is the suitable method for the fixation of flame retardant that polyethylene samples were blended with various flame retardants at 1$25^{\circ}C$ and then blended polymers were crosslinked by the electron beams at room temperature.

• Polymer(Korea)
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• v.32 no.1
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• pp.13-18
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• 2008

For the evaluation of brominated flame retardants included in polymeric electronic devices, we investigated the extraction methods and solvent systems for four different types of polymers of PC (polycarbonate), PP (polyropylene), PET (poly(ethylene terephthalate)) and PBT (poly(butylene terephthalate)) using different solvent systems of hexane/acetone, THF, toluene, and THF/toluene. In order to compare the extraction efficiency of different methods and solvent systems, the deca-BDE (decabromo diphenyl ether) flame retardant was included in PC, PP, PET and PBT systems and subsequently extracted by soxhlet, ultrasonic, accelerated solvent, microwave and supercritical fluid extraction methods. The amount of the extracted flame retardant was monitored to evaluate the extraction efficiency. The ultrasonic extraction method was found not to be acceptable as an extraction method for the polymer systems mainly due to a low salvation efficiency of the organic solvents. Soxhlet, accelerated solvent and microwave extraction methods exhibited over 80% of extraction efficiency for toluene. The supercritical fluid extraction method, which has been used as an extraction method for flame retardants in polymers, showed the extraction efficiencies of ca. 100% for PC and PP in the optimal extraction conditions of $60^{\circ}C$ and 120 bar.