How does the resistance to chalk fading differ between polyethylene and polypropylene?

When comparing the resistance to chalk fading between polyethylene (PE) and polypropylene (PP), several factors come into play. Polyethylene, known for its flexibility and chemical resistance, generally exhibits moderate resistance to chalk fading due to its semi-crystalline structure. However, it can degrade under prolonged UV exposure, leading to surface chalkiness.

On the other hand, polypropylene, while also semi-crystalline, tends to have better resistance to chalk fading because of its higher melting point and superior UV stability when properly stabilized with additives. PP's molecular structure makes it less prone to surface degradation, resulting in longer-lasting color retention compared to PE.

In summary, polypropylene typically outperforms polyethylene in resisting chalk fading, especially in outdoor applications where UV exposure is a concern. However, the specific formulation and additives used in each polymer can significantly influence their performance. For optimal results, choosing UV-stabilized versions of either material is recommended.