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The effect of ultraviolet light on the mechanical properties of polyethylene and polypropylene films
Author(s) -
Raab M.,
Kotulák L.,
Kolařík J.,
Pospíšil J.
Publication year - 1982
Publication title -
journal of applied polymer science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.575
H-Index - 166
eISSN - 1097-4628
pISSN - 0021-8995
DOI - 10.1002/app.1982.070270716
Subject(s) - materials science , polypropylene , composite material , polyethylene , embrittlement , tacticity , irradiation , ultraviolet , low density polyethylene , ultraviolet light , anisotropy , polymer , optics , polymerization , physics , optoelectronics , nuclear physics
Measurements were made of dynamic mechanical response spectra and stress–strain properties at room temperature on films of isotactic polypropylene and low‐density polyethylene prior and after ultraviolet irradiation in a Xenotest 450 apparatus. The period of irradiation that caused a deep deterioration of ultimate mechanical properties influenced the dynamic mechanical properties only insignificantly. This is attributed to the heterogeneous nature of the photo‐oxidative degradation process which is concentrated in a finite number of sites, thus forming crack precursors rather than changing the material properties in bulk. For a biaxially oriented tubular film of low‐density polyethylene, anisotropic embrittlement after exposure in Xenotest 450 was observed. This even reversed the order of strain‐at‐break values in the two main directions of the film. This is remarkably similar to the effect of artificial incisions introduced into the specimens.