Effects of melt reprocessing on volatile emissions and structural/rheological changes of unstabilized polypropylene

Document Type

Article

Publication Date

6-3-2002

Abstract

Emission of volatile organic compounds (VOCs) during multiple melt reprocessing of polypropylene (PP) was studied in this research. An unstabilized commercial grade polypropylene (PP) was processed several times by injection molding to simulate multiple recycling. After each cycle, the PP was non-isothermally heated in a reactor, and the total VOCs emissions were monitored using a flame ionization detector (FID). Cumulative VOCs emissions versus cycle number showed an almost linear relationship. Corresponding structural changes were investigated using Fourier Transform Infrared (FTIR) Spectroscopy, and the results were correlated with rheological properties via melt flow index measurement. The data showed a decrease in viscosity, particularly after the 7th processing cycle. A simulation study was performed by multiple heating and cooling of a single PP sample under static conditions, and in different gaseous (nitrogen, oxygen, air) atmospheres. The results indicate that the actual reprocessing conditions generate emissions whose levels, and the rate of generation are closer to mild thermooxidative degradation rather than a pure thermal degradation. © 2002 Elsevier Science Ltd. All rights reserved.

Identifier

0036107415 (Scopus)

Publication Title

Polymer Degradation and Stability

External Full Text Location

https://doi.org/10.1016/S0141-3910(02)00083-6

ISSN

01413910

First Page

93

Last Page

102

Issue

1

Volume

77

Fund Ref

State of New Jersey Commission on Science and Technology

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