ISSN:
0032-3888
Schlagwort(e):
Chemistry
;
Chemical Engineering
Quelle:
Wiley InterScience Backfile Collection 1832-2000
Thema:
Chemie und Pharmazie
,
Maschinenbau
,
Physik
Notizen:
Accelerated aging of an Initial formulation of a nylon 6,6/poly(phenylene oxide) (PA/PPO) blend resulted in a significant loss in impact strength after a relatively short aging period. Fourier transform infrared (FTIR) spectroscopy showed considerable surface oxidation in air-aged samples. Scanning electron micrographs (SEM) of fracture surfaces showed evidence of embrittlement (glassy skin formation). This brittle skin apparently influenced crack propagation throughout the entire cross section of the test specimens. It was determined by nuclear magnetic resonance (NMR) analysis that the PPO phase of the blend contained a poly(styrene-butadiene) copolymer, probably added as an impact modifier. The susceptibility of the polybutadiene to oxidation, especially at elevated temperature, is believed to have caused the oxidation and surface embrittlement. However, the surface oxidation also resulted in a large loss in molecular weight of the nylon phase (m-cresol-soluble portion) and considerable cross-linking of the PPO phase (chloroform-soluble portion). Samples aged in inert atmosphere showed no skin formation nor loss in impact properties, thus confirming that oxidative degradation caused the embrittlement.
Zusätzliches Material:
10 Ill.
Materialart:
Digitale Medien
URL:
http://dx.doi.org/10.1002/pen.760280603
