What are the differences in thermal degradation between WPC and PVC outdoor trash cans?

When comparing outdoor trash cans made from Wood Plastic Composite (WPC) and Polyvinyl Chloride (PVC), significant differences emerge in their thermal degradation behavior. WPC materials, composed of wood fibers and thermoplastics, experience thermal degradation primarily through the decomposition of lignin and hemicellulose in the wood component when exposed to prolonged UV radiation and high temperatures. This leads to surface cracking, color fading, and reduced structural integrity over time. PVC trash cans, being purely synthetic, undergo dehydrochlorination when heated, releasing hydrogen chloride gas which accelerates further degradation. This results in embrittlement, discoloration, and loss of mechanical strength. While WPC typically shows gradual strength reduction starting around 150°C, PVC begins degrading at lower temperatures (70-100°C) but may include stabilizers to enhance heat resistance. The degradation rate in WPC is significantly influenced by the wood-to-plastic ratio and quality of UV stabilizers, whereas PVC's performance depends heavily on plasticizer content and additive packages. For outdoor applications, WPC generally offers better resistance to heat-induced warping but may suffer more surface deterioration, while PVC maintains better moisture resistance during thermal cycling but becomes increasingly brittle. Understanding these thermal degradation patterns helps consumers select the most suitable material for their specific climate conditions and longevity requirements.