Microfiber Textiles of Adsorbing Materials for Heat Transformations

Adsorbent materials made of hybrid, inorganic/organic, microfibers can be easily produced by electrospinning. Due to the presence of a polymeric component, microfibers coatings and textiles are intended for adsorption heat transformers driven by low-temperature heat sources. In this work, two different systems, SAPO-34 and silica gel microfibers with an adsorbing particles concentration of 68 wt%, have been electrospun using polymethylmethacrylate (PMMA) as polymeric carrier. The thermal stability of hybrid microfibers coatings were characterized by thermogravimetric analysis in the temperature range 25-500 C while water sorption properties were evaluated measuring isobars at 10 mbar and 40 mbar by vacuum thermogravimetry. The mechanical properties of hybrid microfibers were measured by a specially developed micro-tensile tester. Adsorption measures demonstrated that PMMA/SAPO-34 and PMMA/silica gel microfibers maintained all water sorption characteristics of the original adsorbent materials and that PMMA did not occlude the adsorbents porosity. PMMA resulted an ideal component for its thermal stability, good affinity with the adsorbent phases and mechanical resistance. From this point of view, the addition of SAPO- 34 powder has been shown to improve the tensile strength of PMMA/SAPO-34 fabrics compared to pure PMMA microfibers.