Self pressurizing bladder tooling

A composite structure comprising:

• at least one composite ply defining a cavity;
• a bladder arranged within the cavity such that the at least one composite ply is wrapped about the bladder, the bladder comprising:
• a flexible body having a selectively sealable internal chamber;
• and
• a phase change material disposed within the internal chamber, the hollow internal chamber being configured to receive the phase change material when the phase change material is in a first phase and has a first volume, and to accommodate the phase change material when the phase change material is in a second phase having a second volume during curing of the at least one composite ply wrapped about the bladder, the second volume being expanded relative to the first volume, the internal chamber configured to seal the phase change material therewithin, and wherein the bladder is not removable from the cavity.

A bladder for a composite structure comprising:

• a flexible body having a selectively sealable internal chamber;
• and
• a phase change material disposed within the internal chamber, the phase change material configured to be in a first phase and have a first volume when supplied to the internal chamber and to be in a second phase having a second volume responsive to an increase in temperature,
• the second volume being expanded relative to the first volume, wherein the internal chamber is configured to seal the phase change material within the internal chamber when the phase change material is in the second volume;
• and
• the bladder being disposed within a cavity of the composite structure and is configured such that it is not removable from the cavity.