A flexible thermal control composite comprising a natural or synthetic polymer and an endotherm dispersed, distributed and suspended within said natural or synthetic polymer i.e. "P"olymer "C"ontaining an "E"ndothermic "A"gent (PCEA). The PCEA can be formed into thin and thick films. It can be drawn, molded, extruded and spun into fibers or all dimensions. It can be formed and chopped into PCEA mulch. Irrespective its final form, the PCEA can be used in insulating, thermoprotecting, heat absorbing applications on the one hand, and heat maintenance applications of all types on the other.