Linear low-density polyethylene is a semicrystalline ethylene copolymer in which short alkyl branches are introduced by copolymerising ethylene with an alpha-olefin, keeping the chain backbone essentially linear ^[1]. Branch content and branch length set the crystallinity, since the branches are excluded from the lamellae and act as defects that thin the crystals and lower the melting range ^[2]. The result is a density between that of low-density polyethylene, which carries long-chain branching, and high-density polyethylene, which is nearly unbranched, with a stiffness that falls as branch density rises ^[3]. Its melt rheology reflects the absence of long-chain branching, so the flow activation energy is lower than in a branched homopolymer of the same molar mass ^[2].