1. Sichuan University is a 985 university and can participate in projects sent abroad by the state.

You can try to apply, and the chances of being sent to the public are very high. This is what you call public expense.

2. Try to contact HKUST yourself and apply for a scholarship from the school.

The specialty of polymer chemistry is generally short of talents.

So scholarships are generally easy to apply for. You have both TOEFL and GRE.

Then apply for it yourself. It's not difficult.