Dear friend Bingbing Yang

I appreciate you sharing the details of your work—getting zinc oxide well-dispersed in PBT for fiber applications is certainly a complex challenge, especially with issues like precipitation and smoke cropping up. It’s clear you’re tackling this systematically, and I wanted to offer a few thoughts that might help as you refine your process.

First, since MJU Wax 7902 has improved FPV but introduced precipitation, it could be worthwhile to revisit your extrusion parameters. Sometimes, even small adjustments to temperature, screw speed, or cooling rates can make a significant difference in minimizing unwanted precipitation. You might try lowering the extrusion temperature slightly or modifying the cooling profile to see if that helps.

Additionally, exploring alternative dispersants—particularly those designed for high thermal resistance—could be beneficial. Suppliers may offer polyester-compatible waxes that maintain dispersion without causing precipitation at your operational temperatures. It might also be worth experimenting with blends of dispersants or compatibilizers, but I’d recommend proceeding cautiously and documenting each change to track its impact on both dispersion and mechanical properties.

If you haven’t already, reaching out to your suppliers for technical advice can be invaluable. They often have insights into how their products behave under specific processing conditions and may suggest solutions tailored to your setup.

Let me know if you’d like to discuss any of these ideas further or if you have specific results you’d like to troubleshoot together. Wishing you continued progress as you work toward the optimal formulation!

Best regards,

Kaushik