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Titolo:
Photochemical generation of polymeric alkyl-C-60 radicals: ESR detection and identification
Autore:
Qu, BJ; Hawthorn, G; Mau, AWH; Dai, LM;
Indirizzi:
Univ Sci & Technol China, State Key Lab Fire Sci, Hefei 230026, Anhui, Peoples R China Univ Sci & Technol China Hefei Anhui Peoples R China 230026 oples R China Univ Sci & Technol China, Dept Polymer Sci & Engn, Hefei 230026, Anhui, Peoples R China Univ Sci & Technol China Hefei Anhui Peoples R China 230026 oples R China CSIRO, Mol Sci, Clayton, Vic 3169, Australia CSIRO Clayton Vic Australia 3169 O, Mol Sci, Clayton, Vic 3169, Australia
Titolo Testata:
JOURNAL OF PHYSICAL CHEMISTRY B
fascicolo: 11, volume: 105, anno: 2001,
pagine: 2129 - 2134
SICI:
1520-6106(20010322)105:11<2129:PGOPAR>2.0.ZU;2-1
Fonte:
ISI
Lingua:
ENG
Soggetto:
PHOTOINITIATED CROSS-LINKING; LOW-DENSITY POLYETHYLENE; SPIN-TRAPPING ESR; C-60; FULLERENE; BUCKMINSTERFULLERENE; C60; EPR; RESONANCE; ROTATION;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Physical, Chemical & Earth Sciences
Citazioni:
32
Recensione:
Indirizzi per estratti:
Indirizzo: Qu, BJ Univ Sci & Technol China, State Key Lab Fire Sci, Hefei 230026, Anhui, Peoples R China Univ Sci & Technol China Hefei Anhui Peoples R China 230026 China
Citazione:
B.J. Qu et al., "Photochemical generation of polymeric alkyl-C-60 radicals: ESR detection and identification", J PHYS CH B, 105(11), 2001, pp. 2129-2134

Abstract

Electron spin resonance (ESR) spectroscopy has been used to study various alkylfullerene radical adducts generated by UV-photoinitiated reactions between low-density polyethylene (LDPE) and C-60 in the presence or absence ofbenzophenone (BP) as a photoinitiator under different conditions. Photolysis of LDPE/BP/C-60 mixture in toluene at 323 K produced benzylfullerene (RC60) radical adducts, showing a strong ESR signal of g = 2.002 70 with several well-resolved pairs of C-13 satellites. On the other hand, a well-resolved ESR spectrum characteristic of polymeric alkylfullerene (PC60) radical adducts was observed- during UV irradiation of the LDPE/BP/C-60 in benzene or in the molten state (413 K). Detailed analyses of hyperfine structures (hfs) revealed that the ESR spectrum for PC60 radical adducts consisted of three components: (1) a broad singlet at g = 2.002 50 arising from C-60 radical anions; (2) an innermost pair of C-13 satellites; and (3) a 12-line spectrum superimposed on the broad singlet. Spectroscopic simulation allowed the 12-line spectrum to be attributed to the coexistence of two polymeric radical adducts of C-60 (i.e., the tertiary carbon radical adduct, -(CH2)(3)C-C-60., designated as PAC60., and the secondary carbon radical adduct, -(CH2)(2)CH-C-60., designated as PBC60.), which have slightly different g values(g(A) - 2.002 48 and g(B) 3 2.002 44) and integral intensities IA/IB (48.4/51.6). These results clearly indicated the generation of C-60-bonded LDPE materials simply by photoirradiation of LDPE/C-60 with BP as a photoinitiator.

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Documento generato il 31/03/20 alle ore 16:20:33