Combining different analytical approaches to identify odor formation mechanisms in polyethylene and polypropylene

Helene Hopfer, Nina Haar, Wolfgang Stockreiter, Christian Sauer, Erich Leitner

Research output: Contribution to journalArticle

8 Citations (Scopus)

Abstract

In a previous study, we identified carbonyls as highly odor-active compounds in both unprocessed and processed polypropylene (PP) with higher intensities after processing, indicating a temperature-driven forming mechanism. In the presented work, we studied whether (a) these carbonyls are the major odor drivers to the overall odor of polyolefins, (b) their formation is taking place already at moderate temperatures well below the typical processing temperatures, (c) conventional antioxidants in polyolefins can prevent or reduce their formation, and (d) whether reducing the amount of oxygen present can decrease the overall odor. One polyethylene (PE) and one PP were selected, and both stabilized and unstabilized polymer powder samples were exposed to conditions differing in oxygen concentration and aging time. The changes in the volatile fraction as well as the formation of odor-active compounds were monitored using a multidisciplinary approach by combining analytical methods based on gas chromatography (GC), multivariate data analysis, and sensory methods (GC-olfactometry and a sensory panel). Both investigated materials (PE and PP) showed similar degradation products (aldehydes, ketones, carboxylic acids, alcohols, and lactones) which increased dramatically with increasing aging time and the lack of stabilization. Oxidation products, mainly carbonyl compounds, were responsible for the odor of the investigated materials. The main odor drivers were unsaturated ketones and aldehydes with a chain length between six and nine C-atoms. Interestingly, similar odor patterns were found for both stabilized and unstabilized samples, indicating that similar formation processes take place independent of the stabilization. [Figure not available: see fulltext.]

Original languageEnglish (US)
Pages (from-to)903-919
Number of pages17
JournalAnalytical and Bioanalytical Chemistry
Volume402
Issue number2
DOIs
StatePublished - Jan 1 2012

Fingerprint

Polypropylenes
Odors
Polyethylene
Ketones
Aldehydes
Gas chromatography
Gas Chromatography
Temperature
Stabilization
Aging of materials
Olfactometry
Oxygen
Carbonyl compounds
Odorants
Lactones
Processing
Carboxylic Acids
Chain length
Powders
Polymers

All Science Journal Classification (ASJC) codes

  • Analytical Chemistry
  • Biochemistry

Cite this

Hopfer, Helene ; Haar, Nina ; Stockreiter, Wolfgang ; Sauer, Christian ; Leitner, Erich. / Combining different analytical approaches to identify odor formation mechanisms in polyethylene and polypropylene. In: Analytical and Bioanalytical Chemistry. 2012 ; Vol. 402, No. 2. pp. 903-919.
@article{ec252b1d2065479f8b4dc2ca8ac346b4,
title = "Combining different analytical approaches to identify odor formation mechanisms in polyethylene and polypropylene",
abstract = "In a previous study, we identified carbonyls as highly odor-active compounds in both unprocessed and processed polypropylene (PP) with higher intensities after processing, indicating a temperature-driven forming mechanism. In the presented work, we studied whether (a) these carbonyls are the major odor drivers to the overall odor of polyolefins, (b) their formation is taking place already at moderate temperatures well below the typical processing temperatures, (c) conventional antioxidants in polyolefins can prevent or reduce their formation, and (d) whether reducing the amount of oxygen present can decrease the overall odor. One polyethylene (PE) and one PP were selected, and both stabilized and unstabilized polymer powder samples were exposed to conditions differing in oxygen concentration and aging time. The changes in the volatile fraction as well as the formation of odor-active compounds were monitored using a multidisciplinary approach by combining analytical methods based on gas chromatography (GC), multivariate data analysis, and sensory methods (GC-olfactometry and a sensory panel). Both investigated materials (PE and PP) showed similar degradation products (aldehydes, ketones, carboxylic acids, alcohols, and lactones) which increased dramatically with increasing aging time and the lack of stabilization. Oxidation products, mainly carbonyl compounds, were responsible for the odor of the investigated materials. The main odor drivers were unsaturated ketones and aldehydes with a chain length between six and nine C-atoms. Interestingly, similar odor patterns were found for both stabilized and unstabilized samples, indicating that similar formation processes take place independent of the stabilization. [Figure not available: see fulltext.]",
author = "Helene Hopfer and Nina Haar and Wolfgang Stockreiter and Christian Sauer and Erich Leitner",
year = "2012",
month = "1",
day = "1",
doi = "10.1007/s00216-011-5463-8",
language = "English (US)",
volume = "402",
pages = "903--919",
journal = "Fresenius Zeitschrift fur Analytische Chemie",
issn = "0016-1152",
publisher = "Springer Verlag",
number = "2",

}

Combining different analytical approaches to identify odor formation mechanisms in polyethylene and polypropylene. / Hopfer, Helene; Haar, Nina; Stockreiter, Wolfgang; Sauer, Christian; Leitner, Erich.

In: Analytical and Bioanalytical Chemistry, Vol. 402, No. 2, 01.01.2012, p. 903-919.

Research output: Contribution to journalArticle

TY - JOUR

T1 - Combining different analytical approaches to identify odor formation mechanisms in polyethylene and polypropylene

AU - Hopfer, Helene

AU - Haar, Nina

AU - Stockreiter, Wolfgang

AU - Sauer, Christian

AU - Leitner, Erich

PY - 2012/1/1

Y1 - 2012/1/1

N2 - In a previous study, we identified carbonyls as highly odor-active compounds in both unprocessed and processed polypropylene (PP) with higher intensities after processing, indicating a temperature-driven forming mechanism. In the presented work, we studied whether (a) these carbonyls are the major odor drivers to the overall odor of polyolefins, (b) their formation is taking place already at moderate temperatures well below the typical processing temperatures, (c) conventional antioxidants in polyolefins can prevent or reduce their formation, and (d) whether reducing the amount of oxygen present can decrease the overall odor. One polyethylene (PE) and one PP were selected, and both stabilized and unstabilized polymer powder samples were exposed to conditions differing in oxygen concentration and aging time. The changes in the volatile fraction as well as the formation of odor-active compounds were monitored using a multidisciplinary approach by combining analytical methods based on gas chromatography (GC), multivariate data analysis, and sensory methods (GC-olfactometry and a sensory panel). Both investigated materials (PE and PP) showed similar degradation products (aldehydes, ketones, carboxylic acids, alcohols, and lactones) which increased dramatically with increasing aging time and the lack of stabilization. Oxidation products, mainly carbonyl compounds, were responsible for the odor of the investigated materials. The main odor drivers were unsaturated ketones and aldehydes with a chain length between six and nine C-atoms. Interestingly, similar odor patterns were found for both stabilized and unstabilized samples, indicating that similar formation processes take place independent of the stabilization. [Figure not available: see fulltext.]

AB - In a previous study, we identified carbonyls as highly odor-active compounds in both unprocessed and processed polypropylene (PP) with higher intensities after processing, indicating a temperature-driven forming mechanism. In the presented work, we studied whether (a) these carbonyls are the major odor drivers to the overall odor of polyolefins, (b) their formation is taking place already at moderate temperatures well below the typical processing temperatures, (c) conventional antioxidants in polyolefins can prevent or reduce their formation, and (d) whether reducing the amount of oxygen present can decrease the overall odor. One polyethylene (PE) and one PP were selected, and both stabilized and unstabilized polymer powder samples were exposed to conditions differing in oxygen concentration and aging time. The changes in the volatile fraction as well as the formation of odor-active compounds were monitored using a multidisciplinary approach by combining analytical methods based on gas chromatography (GC), multivariate data analysis, and sensory methods (GC-olfactometry and a sensory panel). Both investigated materials (PE and PP) showed similar degradation products (aldehydes, ketones, carboxylic acids, alcohols, and lactones) which increased dramatically with increasing aging time and the lack of stabilization. Oxidation products, mainly carbonyl compounds, were responsible for the odor of the investigated materials. The main odor drivers were unsaturated ketones and aldehydes with a chain length between six and nine C-atoms. Interestingly, similar odor patterns were found for both stabilized and unstabilized samples, indicating that similar formation processes take place independent of the stabilization. [Figure not available: see fulltext.]

UR - http://www.scopus.com/inward/record.url?scp=84856235973&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=84856235973&partnerID=8YFLogxK

U2 - 10.1007/s00216-011-5463-8

DO - 10.1007/s00216-011-5463-8

M3 - Article

C2 - 22048233

AN - SCOPUS:84856235973

VL - 402

SP - 903

EP - 919

JO - Fresenius Zeitschrift fur Analytische Chemie

JF - Fresenius Zeitschrift fur Analytische Chemie

SN - 0016-1152

IS - 2

ER -