Hi PeterSI,
You might also look at a free trial of brand new CheFEM prologue simulation software. This program quickly tells you the dimensional change of engineering polymers (including Nylon 6,6) and composites when exposed to a wide range of chemicals (including Water on 3000 meter depth)...
You might also take a look at a new simulation program, called CheFEM (chemical-mechanical FEM simulation of polymers & composites).
More info at CheFEM simulation
Kind regards,
John