A structural investigation into model linear low-density polyethylene containing precise hexyl branches has been completed using metathesis chemistry. These models based on ethylene/1-octene (EO) copolymers are versions of industrially produced metallocene copolymers; however, they contain exact primary structures and constant methylene sequence lengths. Acyclic diene metathesis (ADMET) polymerization has been used to produce copolymers containing only hexyl branches on every 9th, 15th, or 21st carbon along the backbone of polyethylene. Thermal examination of these macromolecules has demonstrated the first narrow melting profile for EO copolymers with high 1-octene incorporation (111, 67, and 48 hexyl branches per 1000 carbons). Further, a new synthetic methodology has been developed to produce branched, pure diene functional monomers with the ability to produce any model LLDPE in good yields.