Structure investigations of PE-g-LCP copolymers

 Transesterification products – copolymers of semiflexible liquid crystalline polymer SBH 112 grafted to functionalized low molecular mass polyethylene (PEox) obtained by melt polycondensation or reactive blending procedures have been investigated by wide-angle x-ray scattering (WAXS) and scanning electron microscopy (SEM). The x-ray diffraction patterns of PE-g-LCP copolymers obtained via both procedures consist of reflections typical for the orthorhombic crystalline lattice of PE and the single reflection of the solid LCP. The lack of d _hkl variations with respect to those of neat PEox and SBH indicates the absence of interactions in the crystalline phase or that of cocrystallization phenomena between the components of the PE-g-SBH copolymers. The analysis of the crystallinity degree and normalized amorphous and crystalline contributions to the diffraction patterns of the products suggests that both copolymer components are partly miscible in the amorphous phase. The extent of miscibility depends on the copolymer structure, namely on the length of PE segments and SBH grafts. PE segments in PE-g-SBH copolymers obtained by the reactive blending are longer and exhibit a higher crystallizability than those obtained via melt polycondensation. SBH grafts of the copolymers obtained by the reactive blending are also longer than those in the products obtained via melt polycondensation. The morphology of the samples has been interpreted as determined by the different structure of the copolymers obtained by both procedures. Received: 3 April 1996 Accepted: 15 August 1996