I've a simple tutorial on porting DS models to OBJ+MTL for Poser over at...

https://www.deviantart.com/nik-2213/art/Porting-DAZ-Studio-props-to-Poser-friendly-OBJ-MTL-899045469

It uses DS' own export facilities. 

Note MTL may only call 'Diffuse' texture, the Kd, which DS knows as 'Albedo'. You'll need to manually load others via Poser's Material Room.