Thermogravimetric behavior of perfluoropolyether

✍ Scribed by Mitsutoshi Hoshino; Yoshihiro Kimachi; Akira Terada

• Publisher: John Wiley and Sons
• Year: 1996
• Tongue: English
• Weight: 634 KB
• Volume: 62
• Category: Article
• ISSN: 0021-8995
• DOI: 10.1002/(sici)1097-4628(19961003)62:1<207::aid-app24>3.0.co;2-0

✦ Synopsis

In this article, two kinds of perfluoropolyether ( P F P E ) with different terminal groups were investigated using thermogravimetric analysis (TGA), infrared (IR) spectroscopy, gel permeation chromatography (GPC), a n d gas chromatography/gas mass spectrum (GC/MS) analysis. P F P E s with a hydroxyl or carboxylic acid terminal group were more heat stable t h a n was P F P E with carboxylic methyl ester. Perfluoropropylene oxide-type P F P E with a perfluoroethyl terminal group at one end tends t o lose weight more rapidly than does copolymer-type P F P E with dihydroxyl or dicarboxyl methyl ester terminal groups a t both ends. T h e residual weight fraction of P F P E with a perfluoroethyl terminal group was dependent on the average molecular weight. T h e number-average molecular weight of P F P E can be calculated from the peak intensity ratio between the polar group and C -F stretching by measuring the IR spectrum of PFPE. T h e number-average molecular weight of PFPE increased because of the evaporation loss of its low molecular weight fraction and the crosslinking reaction of PFPE with increase in temperature. GC/MS analysis showed t h a t the main product of the pyrolysis of PFPE was hexafluoropropylene. We speculated on the PFPE degradation mechanism and the optimum P F P E chemical structure in terms of heat stability.