Effect of cure shrinkage on the miscibility of a rubber with a thermosetting polymer

✍ Scribed by J. Borrajo; C.C. Riccardi; R.J.J. Williams

• Publisher: Elsevier Science
• Year: 1997
• Tongue: English
• Weight: 338 KB
• Volume: 38
• Category: Article
• ISSN: 0032-3861
• DOI: 10.1016/s0032-3861(96)00958-5

✦ Synopsis

A theoretical simulation of the effect of cure shrinkage on the miscibility of a polydisperse rubber with a trifunctional monomer which undergoes a polycondensation reaction is presented. Both components contribute with an excess volume, calculated according to Simha and Boyer concepts. The free energy of mixing, stated in a lattice model, includes the contribution of holes in both entropic and enthalpic terms. The cure shrinkage is simulated through a decrease in the Van der Waals volume (and the associated excess volume) of the thermosetting polymer with conversion. This leads to a decrease in the absolute value of the entropic contribution and an increase in the value of the term associated with interaction energies. Both factors act against rubber miscibility, thus leading to demixing at lower conversions (compared to the case where cure shrinkage is excluded). The effect is, however, relatively small.