What are the effects of prolonged sun exposure on the mechanical properties of WPC outdoor trash cans?

Prolonged sun exposure significantly degrades the mechanical properties of Wood-Plastic Composite (WPC) outdoor trash cans. The primary damaging agent is ultraviolet (UV) radiation from sunlight. It breaks down the polymer matrix within the WPC, leading to chain scission and a loss of molecular integrity. This photodegradation manifests as surface chalking, color fading, and micro-cracking. Mechanically, this translates to a substantial reduction in key properties. The material becomes more brittle, suffering from decreased impact strength and fracture toughness, making it prone to cracking upon impact. Tensile and flexural strength are also compromised, reducing the can's load-bearing capacity and resistance to deformation. Furthermore, the loss of polymer protection exposes the wood flour to moisture, which can cause swelling and further weaken the composite. While additives like UV stabilizers can slow this process, extended exposure inevitably leads to embrittlement, reduced structural integrity, and a shorter service life for the trash can.