Polymer-based materials and processes suitable for producing panels (10), for example, panels for use in a fan shroud abradable seal (12) of a turbofan engine. Such a process includes introducing constituents of an expandable foam material into a continuous forming apparatus (30) that continuously compounds the constituents into a partially-cured compounded polymeric material, which is then continuously formed with the continuous forming apparatus to produce a continuous form (50) having a constant cross-sectional shape transverse to a continuous forming direction of the continuous forming apparatus. A portion of the continuous form is then deformed to produce a preform (62), and the preform is cured within a restricted volume (60) to cause the preform to expand and produce the panel (10).