THERMAL-DECOMPOSITION AND MICROPORE FORMATION IN PEK, PEEK AND PES

At strain rates greater than about 10 the deformation of polymers is a n adiabatic process which can lead to the generation of very high loca lized temperatures. These may be well in excess of the temperatures re quired for thermal decem position of the polymer to occur. It is specu lated that gaseous products arising from such decomposition may act as the source of microcavities and craze initiators. Experiments are des cribed in which the thermal decem position reaction parameters of poly etherketone, polyetheretherketone, and polysulphone are measured using differential scanning calorimetry and thermogravimetric analysis, and the decomposition products analysed by mass spectrometry. The results indicate that the proposed mechanism could act as a source of micropo res with total pore volumes amounting to several per cent of the mater ial volume.