Physicochemical changes in stabilized, orientated polypropylene films during the initial stages of thermal oxidation

Horrocks, Richard ORCID: 0000-0003-1431-058X and D'Souza, J.A. (1991) Physicochemical changes in stabilized, orientated polypropylene films during the initial stages of thermal oxidation. Journal of Applied Polymer Science, 42 (1). pp. 243-261. ISSN 0021-8995

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Official URL: https://onlinelibrary.wiley.com/loi/10974628/year/...

Abstract

Orientated, stabilized, isotactic polypropylene films have been oven‐aged at 130°C for times shorter than required for their embrittlement. The structural changes occurring during this induction period have been studied using tensile tensiometric, density, thermal analytical (DTA and TGA), and infrared spectrophotometric techniques. After an initially rapid annealing, films show similar time‐dependent changes in tensile, density‐derived crystalline and thermogravimetric behaviors. Comparison with vacuum‐aged sample properties shows that these changes reflect the effects of oxidative attack of polypropylene chains. Infrared examination shows that, even after the longest aging times studied and close to the induction period for embrittlement, the presence of oxidized chain groups is only just discernible. Oven aging reduces post‐fusion oxidative onset and maximum mass loss temperatures determined by TGA. Kinetic analysis demonstrates that the apparent activation energies and Arrhenius factors are reduced during aging as the post‐fusion oxidation mechanism becomes more complex. The results suggest that, during the induction period, changes in both physical and chemical structural features of orientated polypropylene occur which have possible importance in determining the lifetime of the polymer in use.

Item Type: Article
Divisions: University of Bolton Research Centres > Institute for Materials Research and Innovation
Depositing User: Tracey Gill
Date Deposited: 22 Aug 2018 10:53
Last Modified: 22 Aug 2018 10:53
Identification Number: 10.1002/app.1991.070420129
URI: http://ubir.bolton.ac.uk/id/eprint/1883

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