Effect of pressure and temperature history on volume relaxation of amorphous polystyrene

摘要: Control of volume changes with time has a critical industrial relevance for the production objects made thermoplastic materials (obtained, e.g., by injection molding), but this phenomenon is completely disregarded commercial codes simulation processes. In work, attention focused on thermomechanical history relaxation at room conditions an amorphous polystyrene. A set data samples obtained in extremely wide range treatments was collected. Data were analyzed aim applying simplified model basis well-known KAHR model, which describes postprocessing polymers adopting minimum number material parameters. Despite fact that only two times are considered, satisfactorily evolution (either contraction or expansion) after given treatment if appropriate partition free into fractions provided. Furthermore, its present form neglects effect pressure relaxation, thermal (at pressure), starting from melt, both specific and rate treatment. © 2003 Wiley Periodicals, Inc. J Polym Sci Part B: Phys 41: 1526–1537,