EXTENDED CHAIN CRYSTALS OF LINEAR HIGH POLYMERS

Studies of extended chain crystals carried out over the last 10 years have been reviewed. Crystallization in an extended chain conformation is possible either by chain folding followed by extension in the solid state, or by crystallization during polymerization. The equilibrium isometric crystal habit is only rarely exhibited. Crystals which derive from folded chain macroconformation by subsequent chain extension have lamellar habit, crystals which crystallize during polymer-ization often show fibrillar habit because of nucleation limitation. The morpho-logy of extended chain crystals is analogous to folded chain crystals. Their properties have been shown to be close to the extrapolated equilibrium properties