Wood Plastics Composites Product

[Ms Fana87]

Hye all

I'm working with Wood Plastic Composite (WPC) for past 2 years. I'm using Bamboo and wood fiber with PVC, PP and PE polymers. I've few questions that might need urgent solutions:

1. Can I know what is the major contribution to WPC product warping problem?
2. How to solve color fading (for external use) other than using UV stabilizer and Hindered amine Light Stabilizer additives?

Hope anyone can help me. TQ.

Regards
FANA