A branch in a polymer is a side chain that extends from the main polymer chain. Branches can occur naturally during polymerization or be introduced intentionally through specific synthetic methods. Branching affects the properties of a polymer by altering its chain packing, crystallinity, and melt flow behavior.

聚合物中的支链是从聚合物主链延伸出来的侧链。支链可以在聚合过程中自然发生，也可以通过特定的合成方法有意引入。支化通过改变其链堆积、结晶度和熔体流动行为来影响聚合物的性能。