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Characterization of polyetheretherketone and other engineering thermoplastics

Technical Report ·
OSTI ID:6858385

Three engineering thermoplastic materials were characterized by thermal/spectroscopic means to assess their suitability in fiberglass-filled molding resins for Mound applications. The three resins examined were: polyetheretherketone (PEEK) from ICI, Ltd., polyetherimide (PEI) from General Electric, and polyethersulfone (PES) from ICI. Thermogravimetric analysis of the three thermoplastics in N/sub 2/ showed that all had a decomposition onset temperature greater than or equal to 525/sup 0/C with PEEK > PEI > PES. Melt thermal stability analyses of glass-filled PEEK and of PEI showed <1% weight loss after 2 hr (N/sub 2/). Thermomechanical analysis (TMA) of glass-filled PEEK revealed a low temperature (approx. 60/sup -/70/sup 0/C) transition below T/sub g/ (approx. 150/sup 0/C). This transition disappeared on subsequent TMA runs and did not reappear on aging at room temperature, which suggests it was the result of molding stresses. Extra transitions below T/sub g/ were also noted for PES and PEI. Direct probe/mass spectroscopy reconstructed ion chromatograms showed water and phenyl sulfone ions to be present in both PES and PEEK (and volatilized below 200/sup 0/C in vacuum). Water only was observed in PEI. The presence of phenyl sulfone in PEEK was confirmed by FT-IR, and sulfur was found in amounts up to 0.23% by weight in 30% glass-filled molding compounds. A polymerization solvent, such as diphenyl sulfone, is a probable source. Fluoride (from a monomer used in the PEEK polymerization) was also detected in amounts up to 0.17% by weight in the 30% fiberglass molding compounds.

Research Organization:
Monsanto Research Corp., Miamisburg, OH (USA). Mound
DOE Contract Number:
AC04-76DP00053
OSTI ID:
6858385
Report Number(s):
MLM-3141; ON: DE84010668
Country of Publication:
United States
Language:
English