Quantitative Structural Study of Cold-Crystallized PEKK

Poly(ether ketone ketone) (PEKK) is a semicrystalline polymer investigated for highly demanding applications in aerospace, transportation, electronics, and oil & gas industries. The properties required these applications, such as thermomechanical chemical stability, are intimately linked to the crystalline state of material. PEKK exhibits polymorphism that depends, among other factors, on its thermal history. control quantification subject this study. Amorphous (T/I = 60/40, where T stands terephthalic I isophthalic units) films were cold-crystallized at various crystallization temperatures, TC, from 180 280 °C ventilated oven. Based quantitative analysis small-angle X-ray scattering (SAXS), wide-angle (WAXS), differential scanning calorimetry (DSC) data, we propose first time methodology obtain detailed information about PEKK: total crystallinity, relative amount stability forms, form II, melting enthalpy 100% crystallized PEKK. evolutions each crystallinity with TC deduced. form, can be tuned by controlling heating rate °C. evolution lamellar thickness periodicity well cell parameters interpreted discussed relation published results PEEK, (100% T), I). Finally, copolymer 60/40), ΔHm100% (202 ± 20) J/g, was estimated.