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Characterization of plastic‐bonded explosives by pyrolysis gas chromatography and multivariate data analysis part II: Aging studies
Author(s) -
Rietjens M.,
Wils E. R. J.
Publication year - 1995
Publication title -
propellants, explosives, pyrotechnics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.56
H-Index - 65
eISSN - 1521-4087
pISSN - 0721-3115
DOI - 10.1002/prep.19950200503
Subject(s) - chemistry , propane , pyrolysis , gas chromatography , methane , hydrocarbon , principal component analysis , accelerated aging , butane , analytical chemistry (journal) , organic chemistry , chromatography , artificial intelligence , computer science , catalysis
Application of Curie point pyrolysis gas chromatography (Py‐GC) and principal component analysis (PCA) in combination with a new normalization method could show the presence of patterns in PCA score plots not visible with the commonly used normalization method. In the first four principal components (PC's), two patterns were observed which could be attributed to aging and the crosslink density (CD). Aging of PBX samples has a complex effect on the peak loadings on PCI and are difficult to reveal. This in contrast to the peak loadings on PC3 and PC4 where both PC's are dominated by only one compound (respectively, C 5 H 6 and cyclohexene). This means that the formation of both these compounds proceeds independently from each other, i.e., by different mechanisms. It was shown that aging is slowed down in samples containing more of the antioxidant Flexzone. From the correlation matrix a few compounds were found to have very high correlations (> 0.98). This was the case for methane, propane and n‐butane in both unaged and aged samples indicating that these compounds do not originate form moieties that are affected by aging. Also, cis‐ and trans‐butene have such high correlations and were formed in a 0.86:1 ratio, probably through the same mechanism. The absolute intensities decrease upon aging suggesting that both compounds originate form those parts of the polymer that are sensitive to aging. PC2 was related to saturated and unsaturated hydrocarbon compounds. The unsaturated compounds result from the elimination of water (free OH groups) from samples with CD values below 1.