Poly(olefin ketone)s:: Comparison of the effects of CH3 and CH3CH2 side groups on the crystal structure

Polyolefin ketone terpolymers with various concentrations of CH3 and CH2CH3 side groups crystallize with inclusion of substituents in the lattice. The degree of crystallinity falls with side group content in both cases and is lower for materials substituted with the larger CH2CH3 unit. Using considerations of lattice distortion, melting point depression, and changes in the crystal-amorphous interface (assessed by the broadening of the SAXS long period) as criteria, the point at which the lattice begins to exclude side groups was investigated.