Polymer architecture

An effect related to branching is chemical crosslinking - the formation of covalent bonds between chains.

[4] With the continual development of Living polymerization, the synthesis of polymers with specific architectures becomes more and more facile.

Complex architecture polymers can be synthesized either with the use of specially tailored starting compounds or by first synthesising linear chains which undergo further reactions to become connected together.

High-density polyethylene (HDPE) has a very low degree of branching, is relatively stiff, and is used in applications such as bullet-proof vests.

Low-density polyethylene (LDPE), on the other hand, has significant numbers of both long and short branches, is relatively flexible, and is used in applications such as plastic films.

[6] For example, in a free radical polymerisation of styrene, addition of divinylbenzene, which has a functionality of 2, will result in the formation of branched polymer.