Mixed-crystal infrared studies of chain organization in solution-crystallized polyethylene

Abstract

We have extended our earlier technique of mixed-crystal spectroscopy of solution-crystallized polyethylene (PEH) by obtaining low temperature infrared spectra. Band contours resolved by computer analysis showed that the CD₂ bending crystal field doublet has a constant splitting from infinite dilution up to ≈ 10 PEH/ 1 PED. The value of this splitting at infinite dilution was compared with values expected from finite groups of oscillators. It can be concluded from this analysis, as was shown from our earlier work, that folding with adjacent re-entry along (110) planes predominates in these crystals. In addition, we now find that there is a high probability that a molecule will fold back along itself on the next adjacent (110) plane.