Effect of pulse repetition rate and number of pulses in the analysis of polypropylene and high density polyethylene by nanosecond infrared laser induced breakdown spectroscopy

Autor(es)

Leme, Flavio O. ^[1] ; Godoi, Quienly ^{[2, 1]} ; Kiyataka, Paulo H. M. ^[3] ; Santos, Jr., Dario ^[4] ; Agnelli, Jose A. M. ^[5] ; Krug, Francisco J. ^[1]

Afiliação do(s) autor(es)

^[1] Univ Sao Paulo, Lab Quim Analit Henrique Bergamin Filho, Ctr Energia Nucl Agr, BR-13416000 Piracicaba, SP - Brazil

^[2] Univ Fed Sao Carlos, Dept Quim, BR-13565905 Sao Carlos, SP - Brazil

^[3] Inst Tecnol Alimentos, Ctr Tecnol Embalagens, BR-13070178 Campinas, SP - Brazil

^[4] Univ Fed Sao Paulo, Dept Ciencias Exatas & Terra, BR-09972270 Diadema, SP - Brazil

^[5] Univ Fed Sao Carlos, Dept Engn Mat, BR-13565905 Sao Carlos, SP - Brazil

• Tipo de documento: Artigo Científico
• Fonte: Applied Surface Science; v. 258, n. 8, p. 3598-3603, FEB 1 2012.
• Citações Web of Science: 24

Resumo

Pulse repetition rates and the number of laser pulses are among the most important parameters that do affect the analysis of solid materials by laser induced breakdown spectroscopy, and the knowledge of their effects is of fundamental importance for suggesting analytical strategies when dealing with laser ablation processes of polymers. In this contribution, the influence of these parameters in the ablated mass and in the features of craters was evaluated in polypropylene and high density polyethylene plates containing pigment-based PbCrO4. Surface characterization and craters profile were carried out by perfilometry and scanning electron microscopy. Area, volume and profile of craters were obtained using Taylor Map software. A laser induced breakdown spectroscopy system consisted of a Q-Switched Nd:YAG laser (1064 nm, 5 ns) and an Echelle spectrometer equipped with ICCD detector were used. The evaluated operating conditions consisted of 10, 25 and 50 laser pulses at 1, 5 and 10 Hz, 250 mJ/pulse (85 J cm(-2)), 2 mu s delay time and 6 mu s integration time gate. Differences in the topographical features among craters of both polymers were observed. The decrease in the repetition rate resulted in irregular craters and formation of edges, especially in polypropylene sample. The differences in the topographical features and ablated masses were attributed to the influence of the degree of crystallinity, crystalline melting temperature and glass transition temperature in the ablation process of the high density polyethylene and polypropylene. It was also observed that the intensities of chromium and lead emission signals obtained at 10 Hz were two times higher than at 5 Hz by keeping the number of laser pulses constant. (C) 2011 Elsevier B. V. All rights reserved. (AU)

• Processo FAPESP: 07/01052-3 - Avaliação da espectrometria de emissão óptica com plasma induzido por laser para determinação de Ba, Cd, Cr, Pb e Sb em brinquedos
• Beneficiário: Quienly Godoi
• Modalidade de apoio: Bolsas no Brasil - Doutorado