高聚物受紫外线照射会发生光降解。紫外线吸收剂是一类能吸收紫外线或减少紫外线透射作用的化学物质，它能进行能量转换，将高能量紫外光转换成以热能形式或无破坏性较长光波的形式把能量释放出来，从而保护高聚物免遭紫外线破坏。
The polymer will be photodegradated when exposed to UV. UV absorber is a kind of chemical substance that can absorb UV or reduce the transmission of UV. It can convert high-energy UV into heat energy or non-destructive long light wave to release energy, so as to protect polymers from UV damage.