An apparatus for dispensing pressurized material is comprised of a container, a polymeric matrix having a network of macropores located within the container, and a propellant that may be reversibly sorbed with the network of macropores so as to desorb as the partial pressure of the propellant within the container decreases. The network of pores is substantially non-swellable upon sorption and desorption of the propellant during filling and use of the dispensing apparatus. The polymeric matrix may comprise aggregates of macroporous polymeric particles in which the particles define a substantially non-collapsible pore network and the aggregates define interstitial spaces between the particles, and the interstitial spaces are substantially larger than the pore network.