A reaction in which the product of one step generates a reactive species that continues the reaction. Chain reactions are characteristic of chain growth polymerization, where a single initiation event can lead to the addition of many monomers.

一个步骤的产物产生继续反应的活性物质的反应。链式反应是链增长聚合的特征，其中单个引发事件可导致许多单体的添加。(yī gè bù zhòu de chǎn wù chǎn shēng jì xù fǎn yìng de huó xìng wù zhì de fǎn yìng. liàn shì fǎn yìng shì liàn zēng zhǎng jù hé de tè zhēng, qí zhōng dān gè yǐn fā shì jiàn kě dǎo zhì xǔ duō dān tǐ de tiān jiā.)