Characterization of photodegradation of a polyurethane coating by positron annihilation spectroscopy: correlation with cross-link density

被引：28

作者：

Zhang, R ^{[1
]}

Mallon, PE ^{[1
]}

Chen, H ^{[1
]}

Huang, CM ^{[1
]}

Zhang, J ^{[1
]}

Li, Y ^{[1
]}

Wu, Y ^{[1
]}

Sandreczki, TC ^{[1
]}

Jean, YC ^{[1
]}

机构：

[1] Univ Missouri, Dept Chem, Kansas City, MO 64110 USA

来源：

PROGRESS IN ORGANIC COATINGS | 2001年 / 42卷 / 3-4期

基金：

美国国家科学基金会;

关键词：

photodegradation; polyurethane; positron annihilation; free-volume;

D O I：

10.1016/S0300-9440(01)00200-4

中图分类号：

O69 [应用化学];

学科分类号：

081704 ;

摘要：

Photodegradation of a polyurethane coating by Xe arc-lamp irradiation as a function of time is studied by positron annihilation spectroscopy. Doppler broadening energy spectra (DBES) of annihilation irradiation is measured as a function of incident positron energy (0-30 keV). A significant decrease in the S-defect parameter from DBES is observed as a function of irradiation time. This is interpreted as a loss of free-volume and holes during the photodegradation process. The cross-link density in the same system is measured by a solvent (methylene chloride) swelling method and is found to increase as a function of irradiation time. A direct correlation between the increase in cross-link density and the decrease in the S-defect parameter from the DBES data is observed. These results are used to discuss the photodegradation process in terms of chemical and physical changes due to UV-irradiation in protective polymeric systems. (C) 2001 Elsevier Science B.V. All rights reserved.

引用

页码：244 / 252

页数：9

共 25 条

[1] PHOTOOXIDATIVE STABILITY OF ELECTRON-BEAM AND UV CURED ACRYLATED EPOXY AND URETHANE ACRYLATE RESIN FILMS [J].