I want to place a part made with PX6 into a mould and use PX90 around the part to set around it. I have designed the part with features to hold onto the PX90. Will the PX90 adhere to the PX6 part if I rough the surface up or do I need to place some adhesive around the part to adhere it to the PX90 ?

Generally PU bonds to PU in cases like this, however it is not one I have tested personally.

Warren Penalver
Easy Composites / Carbon Mods - Technical Support Assistant