A Rubber-Modified Thermoplastic where the Morphology Produced by Phase-Separation Induced by Polymerization Disappears at High Conversions

摘要

An unexpected experimental finding is reported where the primary morphologydeveloped during polymerization-induced phase separation in a rubber-modifiedthermoplastic disappears at high conversions. This process was evidenced bylight scattering (LS) and scanning electron microscopy (SEM) for a particularcomposition of solutions of polyisobutylene oligomers (PIB) inisobornylmethacrylate (IBoMA), during the free-radical polymerization of themonomer. The primary phase separation produced a dispersion of domains rich inPIB containing significant amounts of the monomer (IBoMA). Polymerization ofthe monomer in these domains occurred at high overall conversions producing thefilling of dispersed domains with a PIBoMA-PIB blend. Under these conditionsthe final material had the appearance of a homogeneous blend. The process mightbe adapted to produce new types of rubber-modified thermoplastics where rubberparticles are replaced by rubber-rich domains that do not exhibit definiteboundaries. Keywords: