Enhancement of the mechanical properties and thermostability of poly(vinyl alcohol) nanofibers by the incorporation of sodium chloride

Abstract

The mechanical properties and thermostability of poly(vinyl alcohol) (PVA) nanofiber mats have been obviously improved by the incorporation of sodium chloride (NaCl). The tensile properties including tensile strength and modulus of membranes with an addition of 1.0 wt % NaCl increased from 2.51 to 4.22 MPa and 33.0 to 176.30 MPa, respectively, more than 160 and 700% of those of the electrospun pure PVA membranes. Moreover, thermogravimetric analysis showed that the initial decomposition temperature (T i ) and the half decomposing temperature (T 50% ) of PVA nanofibers with the addition of NaCl were at least 26 and 59 8C higher than that of pure PVA nanofibers, respectively, indicating a strong interaction between the PVA and the salt ions. V C 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018, 135, 45981.

Effect of solvent and additives on the electrospinnability of BSA solutions

“…These values were 1.1 ± 0.1 MPa, 0.53 MPa and 0.85% for E, σ max and ε max , respectively. This value of E is lower than those reported for PVA electrospun nanofiber mats which typically range from 30 to 50 MPa [77][78][79]. However, it coincides with the values reported for cellulose acetate mats [80], being lower than those reported by Stylianopoulos et al [81], who found an apparent dependence of the E value on the concentration for the polymer solution subjected to the electrospinning process.…”

“…The value of the maximum stress is also lower than those found for other polymer electrospun mats. Thus, σ max typically ranges for PVA from 2.5 to 8.5⋅MPa [78,79,82]. A value of ca.…”

Hydrogels with Gigantic Thermopower for Low-grade Heat Harvesting

“…The structure breaker can disrupt the hydrogen bonds formed by the hydroxyl groups between adjacent PVA chain segments, in addition to the hydrogen bonds between water and structure breaker. On one hand, hydroxyl groups from disrupted hydrogen bonds are exposed to form stronger interaction with ions or H 2 O 40 . On the other hand, the disruption of the hydrogen bonds among water molecules will thin the hydration shell of ions, making ions more exposed and interacting more strongly with the hydroxyl group (as shown in Fig.…”

Role of Ions in Hydrogels with an Ionic Seebeck Coefficient of 52.9 mV K–1

“…On one hand, hydroxyl groups from disrupted hydrogen bonds are exposed to form stronger interaction with ions or H 2 O. 46 On the other hand, the disruption of the hydrogen bonds among water molecules will thin the hydration shell of ions, making ions more exposed and interacting more strongly with the hydroxyl group (as shown in Figure 3e). Conversely, if the structure maker ion promotes the formation of hydrogen bonds, the ion will promote the crosslinking between polymers, as sketched in Figure 3d.…”

“…The structure breaker ion can disrupt the hydrogen bonds formed by the hydroxyl groups between adjacent PVA chain segments, in addition to the hydrogen bonds between water and the structure breaker. On one hand, hydroxyl groups from disrupted hydrogen bonds are exposed to form stronger interaction with ions or H 2 O . On the other hand, the disruption of the hydrogen bonds among water molecules will thin the hydration shell of ions, making ions more exposed and interacting more strongly with the hydroxyl group (as shown in Figure e).…”