Melt-state degradation mechanism of poly (ether ketone ketone): the role of branching on crystallization and rheological behavior

•PEKK ether linkages preferentially undergo chain scission in the melt-state.•PEKK chain scission results in the formation of branched structures.•Branching reduces the degree of crystallinity and peak crystallization temperature but does not influence crystalline morphology or storage modulus at room temperature.