Electron Spin Resonance Study of Polyethylene Irradiated with Ultraviolet Light

Abstract

ESR Spectrum of polyethylene irradiated with ultraviolet light at -196°C was composed of a superposition of two six line spectra, whose total widths were about 155 and _110 gauss, respectively. Free radicals responsible for these two spectra are -CH2-CH-CH2-and -CH2-CH2·. The latter radicals were very reactive and abstracted hydrogen atoms from other parts of polymers to produce former radicals. During the warm-up process, a sharp single! spectrum appeared at about -125°C, which was C=O

ESR Spectroscopy in Polymer Research

“…A few studies have been made on ESR spectra of poly-3,3-bis( chloromethyl)oxethane irradiated with ionizing radiation460, 2250,2258,2259) and UV_light2256, 2276,2277). A three-line spectrum with a hyperfme splitting constant of about 21 G, and a two-line spectrum with a hyperfine splitting constant of about 18 G, were observed after irradiation with an electron beam in vacuum (Fig.…”

“…Several papers have been published on ESR studies of oxygen radicals formed during the irradiation of the following polymers: polyethylene 14,456,1137,1388,1473,1476,1589,1642,1648,1650,1936,2267,2272), polypropylene332, 456-458, 603, 623, 683, 684, 838,1034,1154,1158,1159,1330,1473, 1476,1481,1591,1639,1648,1650,1651,2243) polyisobutylene 1473), , polytetrafluoroethylene62, 888-891, 893,1025,1034,1137,1148,1152,1158,1160,1330, 1432,1478,1480,1520,1534, 1639,1686, 1840,2006,2152,2160,2216,2304,2306,2490) poly(methyl methacrylate) 293,375,395,1137,1473,1645), polystyrene293, 375,836,1941), poly( vinyl chloride) 1254,1390,1642,1648,1651,1788), poly(vinyl acetate) 293,375,1476,1483), poly(oxymethylene) 2091,2252,2266), poly( oxyethylene )1590), poly(2,6-dimethyl-l ,4-phenyleneoxide )2128, 2280), poly-3,3-bis(chloromethyl)oxethane460, 2256,2276,2277), polyquinones202 3), polyamides 451 , 803,1476), and polyurethanes I593 ). Some problems i...…”

The effect of α-tocopherol on the oxidation and free radical decay in irradiated UHMWPE

“…These free radicals recombine with each other and form cross-links in the amorphous portion of the polymer. The free radicals generated during irradiation in the crystalline phase, however, become trapped (8)(9)(10). These trapped free radicals are the precursors to oxidative embrittlement of irradiated UHMWPE in the long term.…”

Pressure‐Induced cis‐to‐trans Isomerization of Poly[(p‐methylthiophenyl)acetylene] Prepared with a [Rh(norbornadiene)Cl]2 Catalyst – A Raman, UV‐Vis, and ESR Study

“…The observed spectra before and after compression are depicted in Figure 6. The microwave power saturation effect [20] in the ESR spectrum of PpMeSPA was examined to determine whether this polymer is composed of two components which are ascribable to cis radical: a and trans radical: b as shown in Scheme 4. It is clear that the line shapes change with increased microwave power (see Figure 6a-b).…”