ABSTRACT
Polyolefin is a group of polymers produced from chemically unsaturated CnH2n as a monomer. Two of the simplest members are polyethylene (PE) and polypropylene (PP).
PE is a readily crystallized thermoplastic. It is available commercially in three major grades: low, high, and ultrahigh (ultrahigh-molecular-weight polyethylene-UHMWPE). UHMWPE is also known as high-modulus polyethylene (HMPE) or high-performance polyethylene (HPPE). UHMWPE has extremely long chains, with a molecular mass usually between 2 and 6 × 106 g/mol. The longer chain serves to transfer load more efficiently across the polymer backbones by strengthening intermolecular interactions, resulting in a very tough material, with the highest impact strength of any thermoplastic presently made. Table 9.1 lists the properties of UHMWPE [1].
