Unsaturated polyester resins (UPRs) are extensively
used by the fiber-reinforced plastic (FRPs) industry.
These resins have the disadvantages of brittleness and
poor resistance to crack propagation. In this study, UPRs
were chemically modified by reactive blending with polyurethane
prepolymers having terminal isocyanate groups.
Hybrid networks were formed by copolymerisation of unsaturated
polyesters with styrene and simultaneous reaction
between terminal hydroxyl groups of unsaturated polyester
and isocyanate groups of polyurethane prepolymer. The
prepolymers were based on toluene diisocyanate (TDI) and
each of hydroxy-terminated natural rubber (HTNR), hydroxy-
terminated polybutadiene (HTPB), polyethylene glycol
(PEG), and castor oil. Properties like tensile strength,
toughness, impact resistance, and elongation-at-break of the
modified UPRs show considerable improvement by this
modification. The thermal stability of the copolymer is also
marginally better
Description:
Journal of Applied Polymer Science, Vol. 100, 449–456 (2006)