Molecular structure and some related properties of polyethylene stretched in the amorphous and crystalline states



The molecular orientation of stretched polyethylene has been estimated separately for the crystalline and amorphous phases by using x-ray and birefringence techniques. It is confirmed that if a hightly crosslinked polyethylene is highly stretched rapidly in the perfectly molten state and cooled to room temperature, a fibrous structure comprised of highly oriented crystallites and almost unoriented relaxed amorphous chains is produced. Some properties such as dynamic mechanical properties and thermodynamic property are discussed in relation to the molecular structure.