PVDF electrospun membranes were prepared by employing different mixtures of solvents and diverse electrospinning parameters. A comprehensive investigation was carried out, including morphology, nanofiber diameter, crystallinity, β-phase fraction, and piezoelectric response under external mechanical strain. It was demonstrated that by using low-toxicity DMSO as the solvent, PVDF membranes with good morphology (bead-free, smooth surface, and uniform nanofiber) can be obtained. All the fabricated membranes showed crystallinity and β-phase fraction above 48% and 80%, respectively; therefore, electrospinning is a good method for preparing PVDF membranes with the piezoelectric properties. Moreover, we considered a potential effect of the solvent properties and the electrospinning parameters on the final piezoelectric properties. When PVDF membranes with different β-phase fractions and crystallinity values are applied to make the piezoelectric transducers, various piezoelectric voltage outputs can be obtained. This paper provides an effective and efficient strategy for regulating the piezoelectric properties of PVDF electrospun membranes by controlling both solvent dipole moment and process parameters. To the best of our knowledge, this is the first time that the influence of a solvent’s dipole moment on the piezoelectric properties of electrospun materials has been reported.

In this work, we explored a microwave-assisted glycolysis process to chemically recycle rigid polyurethane (PU) foam waste to obtain a single-phase product with suitable physio-chemical properties as a secondary raw material for the preparation of new rigid PU products. Such an approach was compared to a conventionally heated (ConvH) process, analyzing the performances of different catalysts. The use of microwaves allowed a 94% decrease in the reaction time scale of rigid PU depolymerization, with a concurrent 45% reduction in energy expense. By using a PU/diethylene glycol mass ratio of 1.5, best performances were obtained with a 30 mmol/100g_PU potassium acetate concentration, both in terms of the product viscosity and aromatic amine byproduct content. The glycolysis products recovered were employed in substitution to virgin polyol for rigid PU foam preparation, showing improved compressive strength and comparable thermal insulation properties up to a 30% content with respect to the traditional non-recycled counterpart.

A multicomponent membrane based on polysulfone nanofibers and titanium dioxide nanoparticles is produced by the coupling of electrospinning and electrospraying techniques. The manufactured product can satisfy a number of conflicting requirements begetting its technical and functional versatility as well as the reliability of the process. As nanoparticle dispersion is a critical issue in nanoparticle technology, their distribution and morphology have been extensively studied before and after electrospraying, and process optimization has been carried out to obtain nanoparticles uniformly spread over electrospun nanofibers. These membranes have been proved to be a good candidate for supported catalysis due to the photocatalytic activity of TiO(2), tested for degradation of CEPS, a mustard agent simulant. At the same time, an effective improvement in filtering properties in terms of pressure drop has also been studied.

The present work examines the influence of different carbon-based fillers on the performance of electrically conductive polymer blend composites. More specifically, we examined and compared the effects of graphene (GR), carbon nanotubes (CNTs) and carbon black (CB) on a PC/ABS matrix by morphological investigation, electrical and physic-mechanical characterization. Electrical analyses showed volume resistivity decreased when the CNTs and CB content were increased, although the use of melt-mixed GR did not really influence this property. For the latter, solution blending was found to be more suitable to obtain better GR dispersion, and it obtained electrical percolation with a graphene content ranging from 0.5% to 1% by weight, depending on the solvent removal method that was applied. There was a gradual improvement in all of the composites’ dielectric properties, in terms of loss factor, with temperature and the concentration of the filler. As expected, the use of rigid fillers increased the composite stiffness, which is reflected in a continuous increment in the composites’ modulus of elasticity. The improvements in tensile strength and modulus were coupled with a reduction in impact strength, indicating a decrease in polymer toughness and flexibility. TEM micrographs allowed us to confirm previous results from studies on filler dispersion. According to this study and the comparison of the three carbon-based fillers, CNTs are the best filler choice in terms of electrical and mechanical performance.