How does chain transfer create branches in low-density polyethylene?

In the context of free-radical polymerization, chain transfer—often referred to as "backbiting"—is the mechanism responsible for creating the branched structure of low-density polyethylene (LDPE).1

Because growing polyethylene chains are highly flexible, the reactive radical located at the end of a chain can curl back toward the middle of its own chain. In this position, the radical abstracts a hydrogen atom from a $C{H}_2$ group along the backbone. This process creates a new radical site in the middle of the chain, from which further polymerization continues, resulting in the formation of a branch.1

This branching can also occur intermolecularly, where a growing chain abstracts a hydrogen atom from a separate, already-formed polymer chain, initiating a new branch from that site. Because these branched molecules cannot pack together as closely as linear chains, LDPE exhibits weaker intermolecular forces, making it more flexible than high-density polyethylene (HDPE).12