The preferred material for repair of fractured denture base is:
REPAIR OF ACRYLIC RESIN DENTURES
An acrylic denture fractured in service can be repaired. Repair resins maybe:

Heat cure (OR)
Self cure

Heat cured resin
These resins are cured at 74oC for 8 hours or more. The use of a heat-cured resin will tend to warp the denture during processing.
Self-cured resin
Although the repair with a self-cured resin invariably has a lower transverse strength than that of the original heat-cured denture base resin, self-cured resins are usually preferred because warpage is insignificant as curing is done at room temperature.
Reference: Mannapallil Basic SCIENCE OF DENTAL MATERIALS, 4th ed page no 561
Chemically cured resin
Heat cured resin
Light cured resin
Vinyl resin