A piezoelectric stack includes a porous resin sheet, and a surface coating layer disposed on an exterior surface of the porous resin sheet, the exterior surface including at least one of a front surface and a back surface of the porous resin sheet, the surface coating layer having a volume resistivity of not less than 1×10.sup.13 Ω.Math.cm, the porous resin sheet and the surface coating layer having different elastic moduli.

Disclosed are a sound absorbing fabric with improved thermal insulation, and a method of manufacturing the same, wherein an inorganic aerogel powder and a thermosetting binder resin are impregnated into a non-woven fabric made of a heat-resistant fiber, wherein the inorganic aerogel powder has a surface modified by a surfactant to be uniformly mixed with and dispersed in a binder resin, thereby forming the sufficient number of micro cavities inside the non-woven fabric and increasing dispersibility of the inorganic aerogel powder, and thus heat resistance, sound absorbing and sound insulating properties, and thermal insulation properties can be significantly improved.

Disclosed are a sound absorbing fabric with improved thermal insulation, and a method of manufacturing the same, wherein an inorganic aerogel powder and a thermosetting binder resin are impregnated into a non-woven fabric made of a heat-resistant fiber, wherein the inorganic aerogel powder has a surface modified by a surfactant to be uniformly mixed with and dispersed in a binder resin, thereby forming the sufficient number of micro cavities inside the non-woven fabric and increasing dispersibility of the inorganic aerogel powder, and thus heat resistance, sound absorbing and sound insulating properties, and thermal insulation properties can be significantly improved.