Answer
Formation of covalent bonds between chains
Work Step by Step
An effect related to branching is chemical crosslinking - the formation of covalent bonds between chains. Crosslinking tends to increase Tg and increase strength and toughness. Among other applications, this process is used to strengthen rubbers in a process known as vulcanization, which is based on crosslinking by sulfur. Car tires, for example, are highly crosslinked in order to reduce the leaking of air out of the tire and to toughen their durability.