The present invention provides a series of baroplastic materials, and systems and methods of making and using such baroplastic materials. In one aspect of the invention, polymeric particles are provided that can be used to produce baroplastic materials under certain pressures and/or below certain temperatures. In one set of embodiments, the polymeric particles include an inner "core" region and an outer "shell" region. In some cases, more than one "shell" region may be present. In another arrangement the particles can include materials, or domains, in nanoscale proximity with each other. Non-particulate materials can also be processed in accordance with the invention. In another aspect of the invention, the invention provides for polymeric particles that can be processed and/or recycled multiple times, without causing significant degradation or alteration in the physical and/or chemical properties of the polymer. In yet another aspect, the invention provides compositions able to form baroplastic materials upon the application of certain pressures, where the composition includes at least two chemically distinct materials in nanoscale proximity to each other. In still another aspect of the invention, a method of mixing two polymers upon the application of pressure is provided.