Application of coincidence Doppler broadening spectroscopy to polypropylene and polyethylene: taking into account the positronium formation

作者：Djourelov N^*; Suzuki T; Yu RS; Shantarovich V; Kondo K

来源：Chemical Physics, 2004, 302(1-3): 179-184.

DOI：10.1016/j.chemphys.2004.04.007

• Doppler broadening
• coincidence technique
• polypropylene
• polyethylene
• positronium formation
• carbonyl group

The coincidence Doppler broadening (CDB) and positron annihilation lifetime (PAL) techniques were applied to study low-density polyethylene (LDPE), high-density polyethylene (HDPE), polypropylene (PP), and antioxidant containing polypropylene (PPA). It was demonstrated that the Doppler-broadened lines for LDPE and PPA could be decomposed into two components a narrow component due to positronium. (Ps) annihilation and another broader one due to free positron annihilation. The determined Ps-component in the Doppler-broadened line was used to calculate the Ps-corrected CDB ratios for HDPE and PP to LDPE. Different ways to compare CDB ratios in polymers were discussed. During a long-term (similar to500 h) positron-irradiation experiment at a low temperature (50 K), a significant enhancement of the carbonyl group concentration in PP was found by means of CDB technique, while the enhancement in HDPE was very slight.

• 出版日期2004-7-12