What are the effects of hydrolysis on polyethylene versus polypropylene outdoor flower boxes?

Hydrolysis, a chemical reaction involving water, significantly affects the durability of outdoor flower boxes made from polyethylene (PE) and polypropylene (PP). Polyethylene, while resistant to moisture absorption, can experience chain scission under prolonged UV and water exposure, leading to brittleness and cracking. Polypropylene, though more hydrophobic, is also susceptible to hydrolysis at high temperatures, accelerating degradation.

PE flower boxes may retain flexibility longer but are prone to surface erosion, whereas PP boxes resist water absorption better but become brittle over time. Environmental factors like humidity and temperature further influence hydrolysis rates. For long-term outdoor use, PP generally outperforms PE in hydrolytic stability, but both require UV stabilizers for enhanced longevity. Choosing between them depends on climate conditions and desired lifespan.