Electrospun Nanocomposite Fibers of Polycarbonate- and Taurine-Modified Boehmite Nanoparticles: What Can Be Learned from Structural and Thermal Investigations?

Abstract

Though the reinforcing properties of inorganic particles in thermosetting nanocomposites have been exploited, the integration of nanoparticles continues to be challenging in terms of their homogeneous distribution and their manipulation, which can contribute to occupational hazards. Due to second encapsulations of nanoparticles, electrospun nanocomposite fibers containing nanoparticles might be an alternative for overcoming these issues, as the nonwoven fibers contain nanoparticles allowing for safer manipulation. Here, the morphology and the thermal properties of electrospun polycarbonate fibers containing taurinemodified boehmite nanoparticles (BNPs) are investigated by means of small-and wide-angle X-ray scattering as well as fast scanning and temperature-modulated fast scanning calorimetry for the first time. The latter techniques allow the investigation of the thermal properties of single fibers at heating rates of up to 10 4 K s −1 keeping their structure intact. An analysis of the scattering data reveals a porous structure of the fibers. The porous structure is quantified regarding the pore volume and the pore size. A constant amount of aggregation is found even for the highly BNP-loaded fibers. Thermal analysis of the fibers reveals a rigid amorphous fraction (RAF), where it is known that the RAF determines the properties of a nanocomposite to a large extent. For the fibers, the RAF amounts up to 40 wt %, which is essentially higher compared to equally formulated PC/BNP composite cast films. The RAF, in the case of fibers, is not only due to the presence of particles in the polymer but also due to the orientation effects induced by the electrospinning process.

Direct and indirect effects on molecular mobility in renewable polylactide–poly(propylene adipate) block copolymers as studied via dielectric spectroscopy and calorimetry

“…Despite these, some questions have opened regarding the structure, namely on partial nano-phase separation, possible self-organization, and, in next level, of the crystal structuring. These points could be further followed in future work, employing, for the amorphous and semicrystalline states small angle X-ray scattering [86][87][88] to illuminate any phase separation, XRD upon targeted thermal treatments to evaluate the degree of crystallinity and investigate alternation on the crystal/lamellar density and to further investigate molecular mobility (by BDS 56 and rheology 89 ) on the initially melt-and cold-crystallized systems.…”

Hierarchically porous and mechanically stable monoliths from ordered mesoporous silica and their water filtration potential

“…SAXS also has the benefit of being able to access closed pores contained within a system, due to differences observed in the contrast. 59 With wide-ranging SAXS data it is possible to ascertain information on both micro- and macro-structures within a sample, even when such structures are only apparent in small volumes, compare the micropore size distributions obtained by nitrogen sorption depicted in Fig. S16.…”

Functional Textile Materials for Blocking COVID-19 Transmission

“…A variety of strategies therefore were developed to address the problems, which are cataloged into four classes: charge enhancer blending, polymer hybridizing, fiber size minifying, and a recharging approach. To elevate the electret performance of fibers, previous efforts mainly focused on the addition of additives such as SiO 2 , TiO 2 , barium titanate, and boehmite nanoparticles, − which always led to the shortcoming of high air resistance. In contrast, a successful report based on sheath/core bicomponent spunbond electret fibers reached a high FE of 98.94% and a low-pressure drop of 37.92 Pa, which used PE/PP as the matrix polymer and magnesium stearate (MgSt) as the charge enhancer (Figure a) .…”