The rapid development in electronics requires high-performance and low-k materials. Introducing additional recyclability to these materials could further promote their application from environmental and economic aspects. In this paper, we report a reversibly cross-linked composite from a newly designed maleimide functionalized POSS (mPOSS) and aromatic polyamide with pendent furan groups (POF). The Diels–Alder reaction between maleimide and furan groups allowed the facile cross-linking of POF by mPOSS, thus significantly improving the thermal and mechanical properties of mPOSS/POF composites. The reversible feature of Diels–Alder reaction also conferred good recyclability to the mPOSS/POF composites. Tensile tests suggested that more than 80% of mechanical properties were retained in reprocessed composites even with multiple reprocessing cycles. Moreover, the porous nature of POSS molecules and the restricted motion of polymer chains by cross-linking significantly reduced the dielectric constant and dielectric loss of composites. These fascinating features of our mPOSS/POF composites make them promising candidate for high-performance, recyclable, and low-k dielectrics.

Solution blow spinning (SBS) is an innovative process for spinning micro/nanofibers. In this paper, polyamic acid (PAA) nanofibers were fabricated via a SBS apparatus and then imidized into polyimide (PI) nanofibers via thermal process. The morphology and diameter distributions of PAA nanofibers were determined by scanning electron microscope (SEM) and Image Tool software, the processing parameters, including PAA concentration, solution feeding rate, gas pressure, nozzle size, and receiving distance were investigated in details. The fourier transform infrared spectroscopy (FTIR) was used to characterize the chemical changes in the nanofibers after thermal imidization. The results showed that the solution concentration exhibited a notable correlation with spinnability, and the formation of bead defects in PAA nanofibers. Solution feeding rate, gas pressure, nozzle size, and receiving distance affected nanofiber production efficiency and diameter distribution. The average diameters of fibers produced ranged from 129.6 to 197.7 nm by varying SBS parameters. Precisely, PAA nanofibers with good morphology were obtained and the average diameter of nanofibers was 178.2 nm with optimum process parameter. After thermal imidization, the PI nanofibers exhibited obvious adhesion morphology among interconnected fibers, with an increased average diameter of 209.1 nm. The tensile strength of resultant PI nanofiber mat was 12.95 MPa.

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Phenolphthalein polyethersulfone (PES-C)/silica (SiO2) composite nanofibrous membranes were prepared via solution blowing. The spinning solutions were prepared by mixing a solution of PES-C in dimethylacetamide with different amounts of colloidal SiO2 in ethylene glycol. Attenuated total reflectance–Fourier transform infrared spectroscopy, wide-angle X-ray diffraction, scanning electron microscopy, thermal gravimetric analysis, and water contact angles were conducted to characterize the properties of composite nanofibrous membranes. The results showed that the thermal properties and surface wettability were improved by the addition of appropriate amount of nano-SiO2. Furthermore, permeation fluxes of pure water and the filtration of starch suspension were measured to evaluate the antifouling property of the PES-C/SiO2 composite membranes.