Radiation Synthesis of Grafted Polymers for Studying Thermoluminescence Characterization and Its Possible Application as a Dosimeter at Low Doses

摘要

Radiation-induced graft copolymerization of binary monomer system acrylic acid/acrylamide (AAc/AAm) (50/50) onto low density polyethylene (LDPE) and polypropylene (PP) films were investigated. Sulfonation was carried out for the prepared graft copolymers using concentrated sulfuric acid (97%) at 60°C for 15 min. The sulfonated grafted films found to have a thermal stability and better hydrophilic character than the grafted ones due to the ionic character resulting from this conversion. The thermoluminescence (TL) characteristics of grafted and sulfonated films were studied with regard to their use as off-line dosimeters in radiotherapy. The structural characterizations were performed by using FTIR, DSC and TGA. The sulfur content was determined by elemental analysis (EA). The TL responses were tested with 60Co beam in the dose range 0.1-7 Gy. The dosimetric characterization has yielded a very good reproducibility, and independence of the radiation energy. The TL signal is not influenced by the dose rate and exhibits a very low thermal fading. Moreover, the sensitivity of the samples compares favorably than that of standard TLD-100 dosimeters. Finally, at the same dose the TL response for LDPE-g-P (AAm/AAc) films is higher than that of PP-g-P (AAm/AAc) and the sulfonated grafted films are more sensitive to radiation than the grafted ones.