Would 3d-printed objects outgas in vacuum?
I found much the same question at Does PLA outgas? An answer there pointed to a NASA outgassing database, Outgassing Data for Selecting Spacecraft Materials, and says that:


  ABS (unknown supplier), MakerGeeks PET and Makerbot PLA have been measured and are listed in the NASA database.


Poster there recommended PLA for lower outgassing, and clear PLA because there would be fewer additives to complicate the problem.