Plasticizing Effect of Ionic Liquid on Poly (vinyl alcohol) with Different Degrees of Polymerization

Abstract

The plasticized poly(vinyl alcohol) (TPVA) was successfully prepared using poly(vinyl alcohol) (PVA) and 1‐butyl‐3‐methylimidazolium bromide (BMIMBr). Plasticizing effect of the degree of polymerization (DP) on PVA was investigated by differential scanning calorimetry (DSC), thermo gravimetric analysis (TGA), Fourier transform infrared spectroscopy (FT‐IR), X‐ray diffraction (XRD), and melt flow indexer (MI). It was found that new hydrogen bonds between PVA and BMIMBr were formed, which was confirmed by the‐OH shift of PVA in FT‐IR analysis. XRD analysis showed that the original lattice and more irregular molecular chain structures in the amorphous region of PVA were destroyed effectively, which was conducive to the decrease of degree of crystallinity. Moreover, the plasticizing effect decreased with the increase of DP duo to more molecular entanglements in PVA. TPVA‐1799 possessed the largest thermal processing window and best melt flowability, which was significant for melt spinning in the future.

Plasticizing effect of 1‐butyl‐3‐methylimidazolium bromide content on poly(vinyl alcohol)

“…However, with the addition of BMIMBr, the crystallization peaks of PVA/IL composites became weak and short, and shifted to lower temperature, this trend being more obvious as the BMIMBr content increased. From Table 1, with the addition of BMIMBr, the T c value of the PVA/IL‐10 wt% composite decreased to 184.2 ± 3.0 °C from the 190.6 ± 1.5 °C of PVA, which was due to the fact that the anions (Br − ) of BMIMBr could form hydrogen bonds with hydroxyl groups of PVA, which could disrupt the regular arrangements of PVA molecular chains and retard the crystallization of PVA 23 . With increasing BMIMBr content, the T c value of PVA/IL composites decreased from 184.2 ± 3.0 to 126.6 ± 1.3 °C.…”

“…The peak at 1093 cm −1 was assigned to the C–O stretching vibration 10,24 . With the addition of BMIMBr, absorption peaks of –OH of the PVA/IL composites shifted to higher wavenumbers, from 3278 cm −1 for PVA to 3295 cm −1 for PVA/IL‐10 wt%, suggesting the formation of hydrogen bonds between anions (Br − ) of BMIMBr and hydroxyl groups of PVA 23 . Absorption peaks of –OH of the PVA/IL composites shifted to higher wavenumbers from 3295 to 3365 cm −1 with an increase of BMIMBr.…”

“…From Table 1, with the addition of BMIMBr, the T m value of PVA/IL composites was lower than that of PVA. This was interpreted in that the anions (Br − ) of BMIMBr could form hydrogen bonds with hydroxyl groups of PVA, which could destroy the intra‐/intermolecular hydrogen bonds in PVA 23 . Moreover, this destructive effect became more and more obvious with increasing BMIMBr, resulting in a constant decrease in T m .…”

Multifunctional Antifreezing Organogel Polyelectrolyte for a Flexible Supercapacitor

“…Meanwhile, the maximum energy density of the PVA/TTY organogel ultracapacitor can reach 4.86 W h kg –1 (Figure S13), which is 58.8% higher compared with that of the PVA organogel-based supercapacitor. The PVA/TTY organogel provides a new direction for the application of low-temperature-resistant energy storage devices with significant specific capacitance and ionic conductivity. , …”

“…The PVA/TTY organogel provides a new direction for the application of low-temperature-resistant energy storage devices with significant specific capacitance and ionic conductivity. 39,40 In complex environment applications, it is crucial for an organogel-based device to exhibit remarkable stability at low temperatures. As displayed in Figure 5a, after three refrigeration cycles between RT, −10, and −20 °C, the electric capacity of the organogel-based ultracapacitor was basically the same as that at room temperature, indicating that the PVA/TTY organogel prepared based on the H 2 O/DMSO binary system had good stability and low-temperature resistance.…”