Complete relaxation map of polypropylene: radiation-induced modification as dielectric probe
Апстракт
The molecular relaxation behaviour of isotactic polypropylene (iPP) exposed to gamma radiation in air to various absorbed doses (up to 700 kGy) has been investigated by dielectric loss (tan delta) analysis; the polar (mainly carbonyl and hydroperoxide) groups that were introduced by radiation-induced oxidation were considered as tracer groups. All relaxation zones (alpha, beta, gamma and delta in the order of decreasing temperature), between 25 K and melting temperature, were studied in the frequency range from 1 kHz to 1 MHz. The changes observed in the dielectric relaxation spectra were related to the modifications in the structural and morphological parameters attributed to exposure of the iPP samples to radiation. Wide-angle X-ray diffraction was used to investigate radiation-induced changes in the crystalline structure and degree of crystallinity, since the alpha relaxation is connected with this phase. Infrared spectroscopy and gel measurements were used to determine the changes ...in the oxidative degradation and the degree of network formation, respectively. Conclusions derived using different methods were compared. This study reveals high dielectric and/or relaxation sensitivity of iPP to gamma radiation. Disappearance of the low-temperature dielectric (gamma and delta) relaxations together with large changes in intensity, position and activation energy of the dielectric alpha relaxation are observed with gamma irradiation and are mainly connected with oxidative degradation in iPP structure.
Кључне речи:
Polypropylene / Gamma radiation / Oxidation / Dielectric relaxation / Polar groupsИзвор:
Polymer Bulletin, 2012, 68, 7, 2033-2047Финансирање / пројекти:
- Хемијско и структурно дизајнирање наноматеријала за примену у медицини и инжењерству ткива (RS-MESTD-Basic Research (BR or ON)-172026)
DOI: 10.1007/s00289-012-0714-1
ISSN: 0170-0839
WoS: 000302255300019
Scopus: 2-s2.0-84861457886
Колекције
Институција/група
VinčaTY - JOUR AU - Suljovrujić, Edin H. PY - 2012 UR - https://vinar.vin.bg.ac.rs/handle/123456789/4770 AB - The molecular relaxation behaviour of isotactic polypropylene (iPP) exposed to gamma radiation in air to various absorbed doses (up to 700 kGy) has been investigated by dielectric loss (tan delta) analysis; the polar (mainly carbonyl and hydroperoxide) groups that were introduced by radiation-induced oxidation were considered as tracer groups. All relaxation zones (alpha, beta, gamma and delta in the order of decreasing temperature), between 25 K and melting temperature, were studied in the frequency range from 1 kHz to 1 MHz. The changes observed in the dielectric relaxation spectra were related to the modifications in the structural and morphological parameters attributed to exposure of the iPP samples to radiation. Wide-angle X-ray diffraction was used to investigate radiation-induced changes in the crystalline structure and degree of crystallinity, since the alpha relaxation is connected with this phase. Infrared spectroscopy and gel measurements were used to determine the changes in the oxidative degradation and the degree of network formation, respectively. Conclusions derived using different methods were compared. This study reveals high dielectric and/or relaxation sensitivity of iPP to gamma radiation. Disappearance of the low-temperature dielectric (gamma and delta) relaxations together with large changes in intensity, position and activation energy of the dielectric alpha relaxation are observed with gamma irradiation and are mainly connected with oxidative degradation in iPP structure. T2 - Polymer Bulletin T1 - Complete relaxation map of polypropylene: radiation-induced modification as dielectric probe VL - 68 IS - 7 SP - 2033 EP - 2047 DO - 10.1007/s00289-012-0714-1 ER -
@article{ author = "Suljovrujić, Edin H.", year = "2012", abstract = "The molecular relaxation behaviour of isotactic polypropylene (iPP) exposed to gamma radiation in air to various absorbed doses (up to 700 kGy) has been investigated by dielectric loss (tan delta) analysis; the polar (mainly carbonyl and hydroperoxide) groups that were introduced by radiation-induced oxidation were considered as tracer groups. All relaxation zones (alpha, beta, gamma and delta in the order of decreasing temperature), between 25 K and melting temperature, were studied in the frequency range from 1 kHz to 1 MHz. The changes observed in the dielectric relaxation spectra were related to the modifications in the structural and morphological parameters attributed to exposure of the iPP samples to radiation. Wide-angle X-ray diffraction was used to investigate radiation-induced changes in the crystalline structure and degree of crystallinity, since the alpha relaxation is connected with this phase. Infrared spectroscopy and gel measurements were used to determine the changes in the oxidative degradation and the degree of network formation, respectively. Conclusions derived using different methods were compared. This study reveals high dielectric and/or relaxation sensitivity of iPP to gamma radiation. Disappearance of the low-temperature dielectric (gamma and delta) relaxations together with large changes in intensity, position and activation energy of the dielectric alpha relaxation are observed with gamma irradiation and are mainly connected with oxidative degradation in iPP structure.", journal = "Polymer Bulletin", title = "Complete relaxation map of polypropylene: radiation-induced modification as dielectric probe", volume = "68", number = "7", pages = "2033-2047", doi = "10.1007/s00289-012-0714-1" }
Suljovrujić, E. H.. (2012). Complete relaxation map of polypropylene: radiation-induced modification as dielectric probe. in Polymer Bulletin, 68(7), 2033-2047. https://doi.org/10.1007/s00289-012-0714-1
Suljovrujić EH. Complete relaxation map of polypropylene: radiation-induced modification as dielectric probe. in Polymer Bulletin. 2012;68(7):2033-2047. doi:10.1007/s00289-012-0714-1 .
Suljovrujić, Edin H., "Complete relaxation map of polypropylene: radiation-induced modification as dielectric probe" in Polymer Bulletin, 68, no. 7 (2012):2033-2047, https://doi.org/10.1007/s00289-012-0714-1 . .