Use an example to show how branching and crosslinking can affect the physical behaviour of a polymer.

A branched polymer is a macromolecule having a side chain or branches that are attached to the main polymer.

A cross-linked Polymer is a three-dimensional structure formed when monomer units are cross-linked together.

Due to branches, it reduces the crystallinity of the polymer by decreasing the ability of close packing of the chains and has a low density and tensile strength. A common example is low-density polyethylene that is (LDPE). It is used in plastic bags, textiles, and containers, as coatings for various packaging materials.

Cross-linked polymer gives a material a better-defined shape, and rigidity and making it brittle through chemical linkages. The vulcanization of rubber, Bakelite, melamine-formaldehyde, etc, are examples.