CRYSTAL-STRUCTURE OF SYNDIOTACTIC POLY(4-METHYL-1-PENTENE)

A model for the crystal structure of syndiotactic poly(4-methyl-1-pent ene) is presented. According to the present analysis, chains having he lical conformations with unit twist t = 210 degrees (1.714 conformatio nal repeat units, each composed of two monomeric units per helix turn) and unit height h = 3.91 Angstrom, corresponding essentially to s(12/ 7)2 symmetry, are packed in a tetragonal unit cell with a = 18.03 Angs trom. The density is 0.878gcm(-3) with four chains in the unit cell, s pace group P ($) over bar 4.