This study investigated the impact of carbonaceous fillers (carbon black, multiwalled carbon nanotubes, graphene, and highly defective graphene) on aromatic and nonaromatic photopolymer resins' properties, such as viscosity, long-term stability, complex permittivity, curing efficiency, final conversion, storage modulus, heat deflection and glass transition temperatures, network density, and DC resistivity. The presented results also highlight challenges that must be addressed in designing and processing carbonaceous filler-based 3D-printed photopolymer resins. The improved dielectric and electrical properties were closely tied to the dispersion quality and filler-matrix affinity. It favored the enhanced dispersion of anisotropic fillers (nanotubes) in a compatible matrix above their percolation threshold. On the other hand, the dispersed filler worsens printability due to the elevated viscosity and deteriorated penetration depth. Nonetheless, electrical and rheological percolation was found at different filler concentrations. This window of despaired percolation combines highly enhanced conductivity with only mildly increased viscosity and good printability.

• Publikační typ
• časopisecké články MeSH

Tubular halloysite (HNT) is a naturally occurring aluminosilicate clay with a unique combination of natural availability, good biocompatibility, high mechanical strength, and functionality. This study explored the effects of magnetically responsive halloysite (MHNT) on the structure, morphology, chemical composition, and magnetic and mechanical properties of electrospun nanofibers based on polycaprolactone (PCL) and gelatine (Gel) blends. MHNT was prepared via a simple modification of HNT with a perchloric-acid-stabilized magnetic fluid-methanol mixture. PCL/Gel nanofibers containing 6, 9, and 12 wt.% HNT and MHNT were prepared via an electrospinning process, respecting the essential rules for medical applications. The structure and properties of the prepared nanofibers were studied using infrared spectroscopy (ATR-FTIR) and electron microscopy (SEM, STEM) along with energy-dispersive X-ray spectroscopy (EDX), magnetometry, and mechanical analysis. It was found that the incorporation of the studied concentrations of MHNT into PCL/Gel nanofibers led to soft magnetic biocompatible materials with a saturation magnetization of 0.67 emu/g and coercivity of 15 Oe for nanofibers with 12 wt.% MHNT. Moreover, by applying both HNT and MHNT, an improvement of the nanofibers structure was observed, together with strong reinforcing effects. The greatest improvement was observed for nanofibers containing 9 wt.% MHNT when increases in tensile strength reached more than two-fold and the elongation at break reached a five-fold improvement.

• Klíčová slova
• biopolymer, electrospinning, gelatine, halloysite, magnetic, nanofibers, nanotubes, polycaprolactone,
• Publikační typ
• časopisecké články MeSH