On Cellulation in Polyethylene Spherulites

Cellulation has been observed to develop with increasing radial distance within growing spherulites of a series of metallocene-catalyzed, ethyl-branched polyethylenes with branch contents ranging from 14 to 37 per 1000 main chain C atoms. The radius to the onset of cellulation and the cell width are both sensibly constant for the same polymer and independent of growth rate. For different polymers, both these quantities fall with increasing branch content. The implications of these novel findings for the crystallization of polymers are discussed.