The MOAB is built by Dynetics and contains approximately 18,000 pounds of tritonal. Tritonal is a mixture of TNT (80%) and aluminum powder (20%). The aluminum improves the brisance of the TNT -- the speed at which the explosive develops its maximum pressure. The addition of aluminum makes tritonal about 18% more powerful than TNT alone.
A Daisy Cutter, by comparison, contains 12,600 pounds (5,700 kg) of ammonium nitrate, aluminum and polystyrene, a combination known as GSX (gelled slurry explosives). GSX is commonly used in mining and is a commercial high explosive that is inexpensive and easy to produce. TNT is a military high explosive.
For more information on MOAB and related topics, check out the links below.