Resin Comparison

The polyesters, vinylesters and epoxies discussed here probably account for some 90% of all thermosetting resin systems used in structural composites. In summary the main advantages and disadvantages of each of these types are:

Polyesters

Advantages:
Easy to use
Lowest cost of resins available (£1-2/kg)

Disadvantages:
Only moderate mechanical properties
High styrene emissions in open moulds
High cure shrinkage Limited range of working times

Vinylesters

Advantages:
Very high chemical/environmental resistance
Higher mechanical properties than polyesters

Disadvantages:
Postcure generally required for high properties
High styrene content
Higher cost than polyesters (£2-4/kg)
High cure shrinkage

Epoxies

Advantages:
High mechanical and thermal properties
High water resistance
Long working times available
Temperature resistance can be up to 140°C wet / 220°C dry
Low cure shrinkage

Disadvantages:
More expensive than vinylesters (£3-15/kg)
Critical mixing
Corrosive handling

David Cripps, Gurit