How does the resistance to warping under humidity differ between PVC and polyethylene?

When comparing PVC (polyvinyl chloride) and polyethylene in terms of warping resistance under humid conditions, key differences arise due to their material properties. PVC is inherently more rigid and less prone to warping under moisture exposure because of its polar molecular structure, which provides better dimensional stability. Polyethylene, on the other hand, is more flexible and hydrophobic, but its non-polar structure makes it susceptible to slight warping or deformation over time in high-humidity environments.

PVC's resistance to moisture absorption helps it maintain its shape, making it ideal for applications like piping and construction where humidity is a concern. Polyethylene, while resistant to water penetration, can experience stress relaxation or creep under prolonged moisture exposure, especially in low-density variants. For high-humidity applications, PVC is generally the superior choice for minimizing warping, whereas polyethylene excels in flexibility and impact resistance but may require additives or cross-linking to enhance its moisture stability.