Crystallization of short aliphatic chains. Part II. An example of even fold surface with adjacent fold reentry and of a transition to chain extension.

An iodine-terminated paraffin, I(CH2)nI, was prepd. from degraded polyethylene [9002-88-4]; the paraffin had 156 .ang. peak mol. length and a sharp mol. wt. distribution. The paraffin was crystallized in lamellae of two thicknesses: (1) thickness close to half the chain length and (2) thickness intermediate between half chain length and fully extended chain. (1) Corresponds to each chain folding once with equal stems and with ends at the surface. In (2) the chain ends must turn into the lattice. In both cases the lamellar thickness was increased by annealing up to complete chain extension.