The effect of depth and duration of UV radiation on polypropylene modification via photoinitiation
Article first published online: 9 JUN 2014
Copyright © 2014 Wiley Periodicals, Inc.
Journal of Applied Polymer Science
Volume 131, Issue 21, November 5, 2014
How to Cite
2014), The effect of depth and duration of UV radiation on polypropylene modification via photoinitiation. J. Appl. Polym. Sci., 131, 41021, doi: 10.1002/app.41021, and (
- Issue published online: 11 AUG 2014
- Article first published online: 9 JUN 2014
- Manuscript Accepted: 13 MAY 2014
- Manuscript Received: 5 FEB 2014
- Natural Sciences and Engineering Research Council (NSERC) of Canada
- Canada Research Chair (CRC) program
- long chain branching;
Linear polypropylene (PP) was modified using UV radiation in the presence of 0.5 wt % of benzophenone photoinitiator to introduce long chain branching (LCB) to the PP backbone. Irradiation was carried out in the solid state and the temperature level was kept below 60°C. The effects of radiation duration and sample thickness on the extent of these branching modification reactions were investigated. Viscoelastic properties, molecular weight, molecular weight distribution, and gel content were determined and compared for runs having different sample thicknesses, irradiated for different times. Comparisons were also conducted with the parent PP and the PP mixed with photoinitiator. It was found that LCB decreased by increasing the thickness of the samples. Conversely, an increase in radiation duration resulted in enhanced LCB but also led to larger gel content in the samples. Based on all these measurements and observations, a mechanism was suggested to explain formation of long chain branches (LCBs) in PP in the solid state via photoinitiation. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014, 131, 41021.